Test sample, Regis NU-713 Quiz 5 (Epidemiology Chapters 11 & 12), Exam 1, Micro Exam 4, PHP 405 midterm, Epidemiology, CPH Exam Epidemiology

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You are an epidemiologist investigating increasing cancer rates reported in Southern California. You choose to utilize a case-control study and subsequently identify 2,000 people living in and around the town of Jericho. Three years ago, 1,000 employees of Jericho Gas & Electric were accidentally exposed to high levels of Hexavalent Chromium VI (HC6) in a hazmat spill. You compare the various cancers in these employees with that of 1,000 citizens who were not exposed to HC6. Forty-two JG&E employees exposed and three citizens not exposed to HC6 developed cancers. Using the 2 x 2 table provided, calculate the odds ratio of developing cancer for those exposed to HC6. (Formula: AD / BC) Cases of Cancer No Cancer Totals Exposed HC6 42 (a) 958 (b) 1000 Not Exposed HC6 3 (c) 997 (d) 1000 Totals 34 1966 2000

Cases who developed cancer were 14.57 times more likely to be exposed to HC6 than controls.

In the previous question Pneumonia is a worldwide concern. Public health officials are worried about the possibility of a new strain of pneumonia becoming a pandemic. You are working for a pharmaceutical company which is developing a human vaccine against this new strain. You are in charge of testing the vaccine effectiveness. You need to determine if one or two doses of vaccine are required. You go collect the following information about the vaccine status of persons who did and did not contract pneumonia after getting either one or two doses of vaccine. Among the 201 cases, 56 had received two doses of the new pneumonia vaccine. Among the 398 controls, 243 had received two doses. You were asked to calculate the odds ratio for persons with one dose of vaccine compared to persons with two doses of vaccine. 1. Interpret the odds ratio using the correct sentence formatting. 2. What does the OR mean? 3. What public health message would you recommend to your supervisor about the need for one dose of vaccine versus two doses?

Cases who developed pneumonia were 4.06 times more likely have received only one dose of vaccine compared to controls. PH message: Two doses of vaccine are needed to prevent illness.

In the previous question: You are investigating an outbreak of RSV in Broncoville. The outbreak is primarily occurring among children ages 1 - 4 years. Two day care centers serve Broncoville. The first day care center, Happy Child, has 33 children ages 1 - 4 enrolled. The second day care, Little Heathens, has 63 children aged 1 - 4 years enrolled. There are 12 cases of RSV in children aged 1 - 4 enrolled in Happy Child and six cases of RSV in children aged 1 - 4 enrolled in Little Heathens. You were asked to calculate the relative risk of developing RSV if a child is enrolled at Happy Child day care versus Little Heathens day care. 1. Interpret your results using the correct sentence format. 2. What does the RR mean? 3. What public health message would you recommend?

Children attending Happy Child day care were 3.82 times more likely to develop RSV compared to children attending Little Heathens. Sending your child to Happy Child may increase their risk of getting RSV. PH: Avoid sending your child to Happy Child day care.

Good for identifying the effects of a rare exposure

Cohort

Cohort study

Compares a group of individuals free of disease against a variety of exposures that are hypothesized to increase or decrease the chance of getting the outcome

Case Control study

Compares a group of individuals who have the disease of interest with a group who does not have the disease

A report showed that more men have heart disease than women. Upon further investigation it was found that more men smoke than women, and smoking is an independent predictor of heart disease.

Confounder

When setting up a 2 x 2 table for a cohort study, what variable goes in cell A? Total A B A + B C D C + D Total A + C B + D A + B + C + D

CorrectD. The number exposed who developed the outcome

Good for formulating, but not testing, a hypothesis; seeks to find relationships between variables.

Correlational

Select all that apply: Case-Control studies are good for:

Cost efficiency, Rare diseases, Multiple risk factors for the same disease,

Good for estimating the prevalence of an exposure or disease in a population at one specific point in time

Cross-Sectional

This statistic describes the excess in risk in absolute terms. It shows the additional number of cases expected per "m" exposures. A. Prevalence B. Incidence C. Risk Ratio D. Risk Difference E. Attributable Fraction

Negative Predictive Value (NPV)

D / (C + D)

You perform a case-control study of kindergarten students with and without attention deficit hyperactivity disorder (ADHD). You discover an odds ratio of 3 for prenatal alcohol exposure. Your interpretation of this is

D. Kindergarten children with ADHD are 3 times more likely to have mothers who drank during pregnancy.

What causes someone to become ill or increases their exposure to the causative agent.

Determinants or risk factors

Select all that apply: Cohort studies are good for

Direct determination of risk, Multiple effects (outcomes) of a single exposure, Rare exposures,

What are the two assumptions which guide epidemiology?

Disease does not occur at random, Disease has causal and preventative factors that can be identified through systematic study of populations.

Which of the following is an advantage of a case control study? A. Bias is the assessment of exposure to the factor of interest is minimized B. Multiple disease outcomes following a selected exposure can be readily studied. C. Dependence on recall by subjects in the study is minimized D. It is possible to determine the true incidence of the disease E. It may be used to study etiology of a rare disease

Functions of H and N proteins

ENTRY AND EXIT

A study found that males metabolize a cholesterol-lowering drug differently than females, resulting in differing cholesterol lowering effects in the two genders.

Effect Modifier

Higher than the expected number of cases.

Epidemic

Cross-Sectional study

Evidence of a link between coffee consumption and gall bladder disease was sought among a sample of 1,123 men and women, 50-64 years of age, in Australia in June of 2006. The men and women were asked to complete a questionnaire regarding their consumption of coffee drinking habits and submit to an examination for the presence of gall bladder disease. No follow-up was conducted. High levels of coffee consumption were weakly associated with the presence of gall bladder disease in women but not men.

Ratio

Expression of two quantities (may or may not be related)

A Type II (beta error) occurs when a screening test produces results in which someone who has the disease or condition tests negative. It is a function of cell D in the 2 x 2 table.

False

An investigator would like to assess the association of melanoma (skin cancer) and exposure to infrared skin tanning services by using a hospital-based case-control study. Hospitalized individuals with melanoma will be compared to hospitalized patients without melanoma (controls). This hospital is located in a low-income area of the city and is famous nationwide for its expertise in melanoma; individuals with melanoma (cases) from all over the country go to that hospital to get the highest quality care that can be provided. However, this hospital is not as well known for other medical conditions. Therefore, cases would come from all over the country and controls will be mostly local low-income individuals. The investigator predicts that an overestimation of the association between melanoma and skin tan services may occur.

False

Cohort studies measure prevalence of a disease.

False

Correlational studies are useful because they can demonstrate causation.

False

Generally, confidence interval decreases as sample size decreases.

False

If a disease is very rare, specificity must be high, or else the few cases present will be missed.

False

In case-control studies, participants are randomized into two groups, one with the disease and one without the disease.

False

Passive surveillance yields data in response to aggressive outreach from local and/or state public health agencies.

False

Receiving insulin shots if you are diabetic is a form of primary prevention.

False

You conduct a study to examine the association between an exposure and an outcome. You calculate a relative risk <1.0. This means that those with the exposure were more likely to develop disease than those without the exposure.

False

A cohort study was conducted with 9,488 residents of Broncoville examining the impact of floor of residence on exposure to West Nile Virus (WNV). Residents were divided into those living on floors 4 or lower (5,080) or those living on floors 5 or higher (4,408). Blood was drawn for antibody testing to WNV. On the lower floors 47 persons were antibody positive and on the upper floors, 7 persons were antibody positive. Using the higher floors as the "exposed" group, develop a 2 x 2 table, showing the relative risk of residence on the upper floors? 1. Calculate the incidence rate per 10,000 persons for people living on floor 5 or higher [1] 2. Calculate the incidence rate per 10,000 persons for people living on floor 4 or lower [2] 3. Calculate the relative risk of developing antibodies to WNV among residents on the upper floors [3] Enter only numbers into your answer. If the answer is in decimal form, place a leading 0 in front of the decimal (ie: 0.89). Round to two decimal places after completing mathematical operations. Calculate the crude RR; do NOT convert to a percentage. Save your answer to the RR calculation for the next question on the exam.

Floors 5 or greater: A / (A+B) = 7 / 4408 = 0.00158802 x 10,000 = 15.88 Floors 4 or less: C / (C+D) = 47 / 5080 = 0.00925197 x 10,000 = 92.52 RR = 0.00158802 / 0.00925197 = 0.17

Experimental

In an attempt to study the effect of vitamin C supplementation on the prevention of the common cold, researchers randomly assigned volunteers to take a prescribed amount of vitamin C or to take a placebo, and then followed up to see if the exposed group developed fewer colds than the unexposed group.

Ecologic or Correlational study

In order to determine if vitamin D (the "sunshine" vitamin) is associated with reduced levels of colon cancer, an epidemiologist identified 10 geographic regions in Sweden. Data on the annual days of sunlight was obtained from the Swedish Meteorological Society and colon cancer rates for each region were obtained from the Swedish National Cancer Registry. The findings indicated that those regions with the most days of sunlight per year had significantly lower rates of colon cancer than those areas with the fewest days of sunlight per year.

Relative Risk is equal to 1 (RR = 1)

Incidence in the exposed and the unexposed is the same.

The California Highway Patrol statistics revealed that more accidents occurred to blue cars than to cars of any other color. The inference that while driving a blue car, one is at higher risk of accident than while driving a car of another color is:

Incorrect, because the comparison is not based on rates

Selection bias

Individuals have different probabilities of being included in a study sample

You are conducting a case-control study of insect repellent use in those with West Nile virus infection. The exposure of interest is

Insect repellent

Select all that apply. Which of the following represent the aspect of "place" in descriptive epidemiology?

Latitude, longitude, and climate, Geography of an area

The relative risk for developing ASHD subsequent to entering this study in men as compared to women is:

Lowest in the oldest age group

The incidence of myocardial infarction (MI) among nonsmokers in the population is 1 case per 1,000 persons. The incidence of myocardial infarction among smokers in the population is 4 cases per 1,000 persons. Assume 35% of the population smokes. Develop a 2 x 2 table. A. Calculate the RR of MI for smokers [1] B. Calculate the attributable risk (AR) for smoking on MI. [2]

MI No MI Smoke 4 996 1000 No Smoke 1 999 1000 5 1995 2000 RR = [A / (A + B)] / [C / (C + D)] RR = (4 / 1000) / (1 / 1000) = 4 RR = 4 Population: 35% smokes = 0.35 RR = 4 AR = [P(RR-1)] / {[P(RR - 1)] + 1} x 100 AR = [0.35 (4 - 1)] / {[0.35 (4 - 1)] + 1} x 100 AR = (1.05 / 2.05) x 100 AR = 0.51219512 x 100 = 51.22%

Which discipline is NOT part of the "Epi Onion"?

Mortician

Select all that apply: Case-Control studies are good for:

Multiple risk factors for the same disease Cost efficiency Rare diseases diseases with long latent periods

OR = 1

No association between exposure and outcome

In 2010, there were 2,900 new cases of breast cancer diagnosed among women in Alabama and 200 new cases diagnosed among women in Alaska. Based on these data, is it accurate to say that the incidence rate of breast cancer is higher in Alabama than Alaska? Why or why not?

No, it is also necessary to know the size of the population and the amount of follow-up time in each state

Select all that apply: In order to be a confounder, the variable must

Not be an intermediate variable in the causal pathway between exposure and disease, Be a risk factor for the disease of interest, Be associated with the exposure under study

The theory that there is no association between the exposure and the outcome.

Null hypothesis

Proportion

Number in which the numerator is included in the denominator (also called a percent)

Prevalence

Number of existing cases in a population over a set time

Colistin is new or old antibiotic with low or high therapeutic index?

OLD / LOW

A case-control study was conducted in Broncoville to evaluate whether the amount of time spent watching The Walking Dead on AMC influences the risk of believing the zombie apocalypse could happen. Exposure was divided into those watching summer (or midwinter) reruns of AMC's The Walking Dead more than five hours a week or watching The Walking Dead only occasionally if at all. Investigators selected 500 cases from the Broncoville health registry and matched 1000 controls. The study found 357 cases and 77 controls watched more than five hours of AMC's The Walking Dead per week. Develop a 2 x 2 table. Calculate the odds ratio for cases who watch greater than five hours of AMC's The Walking Dead each week. Interpret the results.

OR = 29.93 Cases are 29.93 times more likely to watch greater than five hours of AMC's The Walking Dead a week compared to controls. Watching a The Walking Dead may increase the risk of believing a zombie apocalypse could happen.

Every year, malaria causes widespread illness in people who visit tropical countries. As an epidemiologist, you have been tasked with trying to understand more about the risk factors which influence the likelihood of becoming infected with malaria in people from Broncoville who visit tropical countries on vacation. You conduct a case-control study with 79 cases and 158 controls. Among the 79 cases of malaria, 22 reported consistent use of insect repellant. Among the 158 controls, 107 reported consistently using insect repellant. Develop a 2 x 2 table. Calculate the odds ratio for cases without consistent use of insect repellent. What does this mean?

OR = 5.44 Cases were 5.44 times more likely to NOT consistently use insect repellant than controls. Lack of consistent insect repellant may increase the risk for contracting malaria when visiting tropical countries.

Pneumonia is a worldwide concern. Public health officials are worried about the possibility of a new strain of pneumonia becoming a pandemic. You are working for a pharmaceutical company which is developing a human vaccine against this new strain. You are in charge of testing the vaccine effectiveness. You need to determine if one or two doses of vaccine are required. You go collect the following information about the vaccine status of persons who did and did not contract pneumonia after getting either one or two doses of vaccine. Among the 201 cases, 56 had received two doses of the new pneumonia vaccine. Among the 398 controls, 243 had received two doses. Develop a 2 x 2 table. 1. Calculate the odds ratio for persons with one dose of vaccine [1] Enter only numerals into your answer. Round to two decimal places after completing mathematical operations. Save your answer to the OR calculation for the next question on the exam.

OR = AD / BC OR = (145 x 243) / (56 x 155) = 35,235 / 8,680 = 4.06

Calculate the odds ratio for the following table and interpret your results. Round to two decimal places after completing mathematical operations. Express your answer as a crude odds ratio: place a leading 0 in front of the decimal (ie 0.89). Seat Belt Use and Emergency Room Visit for Drivers ER Visit Yes ER Visit No Seat Belt Yes 53,947 499,419 553,366 Seat Belt No 12,241 29,155 41,396 66,188 528,574 594,762

OR= 0.26 If you wear your seat belt, you are 74% less likely to have an ER visit after a motor vehicle accident. Wearing a seatbelt is a protective factor.

Recall Bias

Occurs when an individual with a disease/outcome is concerned about remembering potential causes

Interviewer Bias

Occurs when an investigator tends to precisely question cases, inadvertently improving data quality

Berkson's Bias

Occurs when hospitalized patients are not representative of the target population

Reporting Bias

Occurs when individuals emphasize the importance of an exposure they believe to be important

Non-Response Bias

Occurs when individuals who fail to repond to a call to participate in a study are different from those who do respond

Misclassification

Occurs when investigators erroneously place study subjects in the incorrect exposure/outcome category

Exclusion Bias

Occurs when investigators fail to include potential study subjects to prevent confounding

Publicity Bias

Occurs when study subjects respond to a call for cases because the topic has been in the media

Selection Bias

Occurs when the relationship between exposure and disease is different for those who participate and those who would be theoretically eligible for study, but who do not participate which results in a distortion of the study findings. Examples include healthy worker effect bias, nonresponse bias, etc.

From a case-control study, one will be able to calculate

Odds ratio

Internal Validity

Overall study results are close to the truth about the population under study

Communities P and Q have equal age-adjusted mortality rates. Community P has a lower crude mortality rate than Q. One may conclude that:

P has a younger population than Q

When a new treatment is developed that prevents death but does not produce recovery from a disease, the following will occur

Prevalence of the disease will increase.

State the main differences between primary, secondary, and territory prevention

Primary: occurs before the pathological onset of disease and its aim is to block the start of disease. Secondary: takes place from the pathological onset to the occurrence of clinical symptoms. its aim is to delay the onset and duration of symptomatic disease and improve survival. Tertiary: takes place after preclinical symptoms develop. aim is to slow or block the progression of disease and improve survival.

Investigators are studying an outbreak of TB in a Russian prison whose population is 1500. They found that 146 prisoners on Cell Block A were diagnosed with TB. On Cell Block B, seven prisoners were diagnosed with TB. The two Cell Blocks are completely isolated from each other and each contain 750 prisoners. Develop a 2 x 2 table calculating the Odds Ratio (OR) for Cell Block A. Interpret the OR.

Prisoners on Cell Block A are 25.66 times more likely to be diagnosed with TB. Being assigned to Cell Block A is dangerous to prisoners' health.

A prospective cohort study was conducted over a 10 year period to evaluate the relationship between supplemental use of calcium and the risk of hip fractures in post-menopausal women. Of the 500 women who took calcium, 30 had hip fractures and of the 500 women who did not regularly take calcium, 50 women had hip fractures during this time. Develop a 2 x 2 table. What is the relative risk of taking calcium as a supplement? What does it mean? You will need to convert to a percentage to answer this question correctly.

RR = 0.60 Women who took calcium supplements were 40% less likely to have a hip fracture. Calcium supplements are a good strategy to prevent hip fracture.

A retrospective cohort study is conducted to evaluate the relationship between supplemental use of calcium and the risk of hip fractures in post-menopausal women. There were 500 women in each group. Thirty women in the supplement group had hip fractures during the 10 year observation period and 50 women in the group not taking calcium supplements had hip fractures during this time. Develop a 2 x 2 table. What is the relative risk of taking calcium as a supplement? What does it mean?

RR = 0.60 Women who took calcium supplements were 40% less likely to have a hip fracture. Calcium supplements are a good strategy to prevent hip fracture.

An ambi-directional cohort study was conducted to evaluate the relationship between obesity and the risk of heart disease in people who primarily eat out as opposed to eating at home. Investigators selected 800 individuals for study, 400 in each group. Of those who primarily eat out, 137 people were found to be obese and 42 people who primarily eat at home were found to be obese. Develop a 2 x 2 table. What is the relative risk of eating out in relation to heart disease? What does this mean?

RR = 3.26 People who primarily eat out are 3.26 times more likely to have heart disease than those who primarily eat at home. Eating at home is a good health strategy to prevent heart disease.

In a retrospective cohort study, 22,669 inpatient hospital records were examined to evaluate the relationship between nursing patient load and central line catheter infections (CLABSI). Nurse to patient ratios were defined as "light" being four or less patients per nurse and "heavy" as five or more patients per nurse. 17,908 patients consistently had a nurse with a "heavy" patient load and 4,761 patients consistently had a nurse with a "light" patient load. Of patients assigned to a nurse with a "heavy" patient load, 1,062 CLABSI infections occurred. Patients assigned to a nurse with a "light patient load had 71 CLABSI infections. Develop a 2 x 2 table. Determine the relative risk of patients getting a CLABSI if they have a nurse assigned to them with a "heavy" patient load. What does this mean?

RR = 3.98 Patients with a nurse assigned to them with a "heavy" patient load were 3.98 times more likely to get a CLABSI infection than those who had a nurse with a "light" patient load. "Heavy" nurse to patient ratios increase the likelihood of CLABSI infections.

Calculate the relative risk for those wearing their seatbelts. Interpret your results. Round to two decimal places after completing mathematical operations. Express your answer as a percent. Seat Belt Use and Emergency Room Visit for Drivers ER Visit Yes ER Visit No Seat Belt Yes 53,947 499,419 553,366 Seat Belt No 12,241 29,155 41,396 66,188 528,574 594,762

RR = 67%. People who wear seatbelts in motor vehicle accidents are 67% less likely to have an ER visit than people who do not wear their seat belts.

Choose the best answer for the following: Number of women in Woodbury who died from lung cancer in 2014 divided by Number of women in Woodbury who died from breast cancer in 2014

Ratio

What does does this format indicate? 7 : 2

Ratio

In order to assess how strongly related an exposure is to a disease, which would be the best health statistic?

Relative risk

Secular Trends

Represents long-term changes in morbidity or mortality patterns

Cyclic Patterns

Represents periodic, often predictable, increases in the frequency of a particular cause of morbidity or mortality

Investigates rare exposures in a group of subjects to determine probable causes of a disease with a long latent period. Researchers may use health and other official records to retrieve data from prior years or decades.

Retrospective Cohort

You will be studying all of those born in 1953 within a 100 mile radius of the Hanford nuclear facilty. What sort of study will you be conducting?

Retrospective cohort

Which of the following is NOT part of understanding the distribution of a disease?

Risk factors

Tertiary Prevention

Seeks to promote rehabilitation, restoring patients to a maximum optimal functional level

Sensitivity

Sensitivity is a measure of a screening tests validity. It's the probability that a screening test classifies as positive those individuals who have a preclinical disease

Which of the following are part of the "Epi Onion"

Statistics Microbiology Biology Medicine

In the case study on baldness and CHD, the "crude" or overall 2 x 2 table showed that men who were bald were 4.08 times more likely to develop CHD than men who were hairy. To explore age as a possible confounding variable, what did you do next?

Stratified the group by age into older and younger groups to explore further

OR > 1

Suggests a posible risk factor between exposure and outcome

OR < 1

Suggests a possible protective factor between exposure and outcome

Prospective Cohort study

The Nurses Health Study is an example of this type of study. The initial study's data collection began in 1976, and enrolled approximately 120,000 married female nurses between the ages of 30-55 years who were registered in 11 states in the US. The original objective of the study was to evaluate the long-term effects, if any, of oral contraceptive use. Follow-up questionnaires were mailed at 2 year intervals to update exposure information and obtain data on health outcomes. The study has since expanded its purpose to look at nutrition and other behavioral factors and disease, and continues today to be a rich source of information, following women to examine risk factors and health outcomes among women.

External Validity

The ability to generalize beyond a set of observations to a universal statement (ie: one can draw unbiased inferences to a target population)

Surveillance

The act of monitoring the health of the population

Mean

The average, a value that is computed by dividing the sum of a set of terms by the number of terms

The most likely explanation for the differences in rates of ASHD between the initial examination and the yearly follow-up examinations in men is

The initial examination measures the prevalence of ASHD, whereas the subsequent examinations primarily measure the incidence of ASHD

Mode

The most frequent value(s) in the data set

Prevalence is defined as:

The number of disease cases in a population at a given time. It is calculated by dividing the disease cases at a specified time by the number of persons at risk for having the disease at that specified time.

Prevalence is defined as:

Incidence is defined as:

The number of new cases in a population at a given time. It is calculated by dividing the number of new disease cases at a specified time by the number of persons at risk for having the disease at that specified time.

Incidence is defined as:

Population Attributable Risk (PAR)

The proportion of the incidence of a disease in the population (exposed and unexposed) that is due to exposure. It is the incidence of a disease in the population that would be eliminated if exposure were eliminated.

Median

The value in the center of the the data set when ordered from lowest to highest

Relative Risk is greater than 1 (RR > 1)

There is a larger incidence of the disease in the exposed than in the unexposed and the exposure to the factor seems to increase the probability of developing the disease.

Relative Risk is less than 1 (RR < 1)

There is a smaller incidence in the exposed than in the unexposed and the exposure to the factor seems to decrease the probability of developing the disease.

Experimental study

To see if hypnosis could reduce chronic pain, investigators randomly assigned 120 patients with osteoarthritis to either hypnosis therapy or a control group. Pain levels were checked on all patients every three months during the 12-month study using validated pain measures. Those assigned to the hypnosis group reported reduced pain compared to those in the control group after three and six months, but not after nine or twelve months of follow-up.

18. Emerging disease are a problem worldwide, even in highly developed regions of the world True False

True

32. Humans serve as an unexpected reservoir for West Nile Virus True False

True

47. Morbidity statistics more precisely describes the public health status of a population than mortality statistics True False

True

6. Beginning in ~2007, HCV yearly U.S mortality surpassed HIV True False

True

A Type I (alpha error) occurs when a screening test produces results in which someone who does not have the disease or condition tests positive. It is a function of cell B in the 2 x 2 table.

True

A screening test can be highly reliable but produce invalid (untrue) results.

True

All proportions are ratios, but not all ratios are proportions.

True

An ecological fallacy is an error of reasoning (bias) which occurs when an association between variables in a target population is applied to individuals members of that population (or vice versa).

True

An ecological fallacy is the bias that may occur because an association found at the population level does not necessarily represent the association found at the individual level.

True

An example of active surveillance is when someone from the public health arena seeks information (makes calls or sends faxes); it is more time consuming and expensive, but collects more complete data. An example might be calling hospitals to see if anyone with a specific illness type had been admitted in the past week. An example of passive surveillance is when someone sits at their desk and lets the reportable information come in. Passive surveillance would be compiling yearly statistics for the case reports that have been received for a specific reportable disease.

True

Another name for systematic error is bias.

True

Another word for "determinants" of disease is "risk factors."

True

Bias is an error in design or execution of a study that produces results that are consistently distorted in one direction and lead to an incorrect assessment of the association between the factor and the disease under study.

True

Case-control studies are always retrospective.

True

Case-control studies are limited to investigating only one outcome.

True

Coevolution increases the virulence of pathogens when the pathogen relies on host to host transmission. True False

True

Cohort studies may be either retrospective, prospective or ambi-directional.

True

Descriptive studies describe the general characteristics of the distribution of a disease particularly in relation to person, place and time.

True

Getting your flu shot is a form of primary prevention.

True

If a disease is very lethal and early detection markedly improves prognosis, high sensitivity is necessary.

True

In 2009, six people died of H5N1 avian influenza out of 18 persons infected with H5N1 avian influenza. This means the case fatality rate was 33%.

True

In epidemiology, a determinant is a factor or event capable of bringing about a change in health.

True

Relative risk may be less than one (decreased risk in the exposed group) or greater than one (increased risk in the exposed group).

True

Screening is a form of secondary prevention used to detect a disease in individuals without signs or symptoms of that disease.

True

Sensitivity may be increased but only at the expense of specificity.

True

The frequency of disease occurence may differ from population to population.

True

42. The most common HAI's are:

UTIs

Select all that apply: Examples of data sources which can be used for surveillance include

Vital Records (births, deaths, marriages, divorces, etc), Medical Records (medical conditions, demographics, etc) Insurance Data (medical visits, use of certain procedures, costs, prescription utilization, etc, Census data (income, race, family size, etc)

The odds ratio (relative odds) obtained in a case-control study is a good approximation of the relative risk in the population when the following conditions are met:

When the cases studied are representative, with regard to history of exposure, of all people with the disease in the population from which the cases were drawn; when the controls studied are representative, with regard to history of exposure, of all people without the disease in the population from which the cases were drawn; and when disease being studied does not occur frequently

In 1945, 1,000 women worked in a factory painting radium dials on watches. The incidence of bone cancer in these women up to 1975 was compared with that of 1,000 women who worked as telephone operators in 1945. Twenty of the radium dial workers and four of the telephone operators developed bone cancer between 1945 and 1975. Develop a 2 x 2 table and determine relative risk of developing bone cancer for radium dial workers:

Women who worked in the radium dial watch factory were 5 times more likely to get bone cancer than those who were telephone operators during the same time period. Working at the radium dial watch factory was not a good career choice.

A case-control study is characterized by all of the following EXCEPT:

- Cases with the disease are compared to controls without the disease

Only one outcome may be studied, but many risk factors or exposures may be assessed.

- case-control study

Describe the essential feature and prupose of an intent-to-treat analysis

-an intent-to-treat analysis includes all individuals who were randomly allocated to the treatment and comparison groups, regardless of whether they completed or even received their assigned regimen. this type of analysis preserves the baseline comparability and gives inofmration on the effectiveness of the treatment under real-life conditions

c. biased information on the outcome

-mask investigators to group assignment

b. preventive and therapeutic trials

-preventive: investigate measures that stop or delay the onset of disease -tehreapeutic: investigate measures that treat existing disease

b. lack of baseline comparability

-randomize a large number of study subjects

Broncoville has a population of 467,443. In 2014, there 958 deaths in the population from all causes. There were 153 cases of community acquired pneumonia (PNA) identified. In 2014, 38 people died of PNA. What is the crude mortality rate per 1,000 population in 2014?

2.05 deaths per 1,000 population in 2014

In Broncoville on May 31st, 2014 there were 308,958 dialysis patients and 4,602 transplant-dependent patients. At that time, there were approximately 5.7 million citizens in Broncoville. a. What is the prevalence rate per 100 for dialysis patients [1]? b. What is the prevalence rate per 100,000 transplant-dependent patients [2]?

5.42, 80.74

Sensitivity

A / (A + C)

Epidemic curve

A graphical representation of the number of cases of illness by time

When setting up a 2 x 2 table for a cohort study (below), the exposures should be placed at (A or B) [1] and the outcome should be placed at (A or B) [2]. Use only uppercase letters.

A, B

Fluoridation of water would be an example of: A. A primary prevention strategy B. A secondary prevention strategy C. A tertiary prevention strategy D. It is not a prevention strategy

A. A primary prevention strategy

Prevalence

All cases (new and old) in a population at risk over a specified time

Which of the following are determinants of disease? (Select all that are correct)

Carcinogens or chemicals, Behaviors/habits/lifestyles, Socio-political factors,

Place Variables

Census Tracks Neighborhoods Cities Counties States Regions Countries Urban Area Rural Area Schools Indoor Outdoor Home Work

Advantages of case-control studies include all except

Clearly establishes a sequence of events

Specificity

D / (B + D)

Used to assess the association between exposure and disease rates among different populations during the same time period

Ecologic

Examples of descriptive studies that provide data on individuals include all except:

Ecological studies

The "normal" or expected amount of disease occurrence.

Endemic

Good for proving an association between an exposure and an outcome

Experimental

16. All immunogens are antigens True False

False

36. If the incidence of a disease is high and the mortality of the disease is low the prevalence will be: High low

High

Misclassification

Interviewers ask study participants to indicate their nationality. An interviewer forgets to ask this question and places an Asian participant in the Chinese category, when that participant is really Japanese.

Who is the "father" of Epidemiology?

John Snow

Incidence

New onset cases in a population over a set time

Incidence

New onset cases in the population at risk over a set time

Select all the apply to a population at risk in epidemiology:

People who share life styles/life events, People who live in a certain geographic area, People who use the same resources, A group with common characteristics

The key elements of descriptive epidemiology.

Person, place, and time

Follows a group of subjects over time, first collecting baseline health data and possible exposure information, then investigating the outcomes as they manifest.

Prospective Cohort

What is the primary difference between public health and medicine?

Public health focuses on preventing diseases in communitites, and medicine focuses on treating diseases at the individual level.

What does does this format indicate? 1.7 million : 2.5 billion

Ratio

Secondary Prevention

Seeks to diagnose disease early and begin treatment; screening

Primary prevention

Seeks to lower the occurence of disease: health promoting behavior, health education, protective equipment, vaccination

In the case study on baldness and CHD, ultimately what did you determine?

That age was a confounding variable because adjusting for age changed the relative risk

In a study of a disease in which all cases that developed were ascertained, if the relative risk for the association between a factor and the disease is equal to or less than 1.0, then:

There is either no association or a negative association between the factor and the disease

Time Variables

Time of onset Time of Diagnosis

Worldwide one of the most common causes of death in HIV positive patients is TB (tuberculosis). True False

True

Interviewer bias

When information is solicited differently from different study groups (e.g. exposed versus non-exposed)

You are a healthcare worker part of a Peace Corps group in Rwanda. You have been asked to track the number of home visits you make each year and the number of people you saw with various diseases. You made a total of 1,789 home visits last year. You saw 213 children with diarrhea and 88 people with pneumonia. 1. Calculate the incidence of diarrhea cases [1] 2. Calculate the incidence of pneumonia cases per 1000 home visits [2]

You are a healthcare worker part of a Peace Corps group in Rwanda. You have been asked to track the number of home visits you make each year and the number of people you saw with various diseases. You made a total of 1,789 home visits last year. You saw 213 children with diarrhea and 88 people with pneumonia. 1. Calculate the incidence of diarrhea cases 213 / 1789 = 0.11906093 = 0.12 2. Calculate the incidence of pneumonia cases per 1000 home visits 88 / 1789 = 0.04918949 x 1000 = 49.19

33. Influenza regularly infects all of the following EXCEPT? a. Humans b. Bears c. Birds d. Pigs

b. Bears

17. "Typhoid Mary" is an infamous example of a: a. pathogen b. carrier c. vehicle d. common source

b. carrier

48. After the 2010 earthquake in Haiti there was an outbreak of Vibrio cholera, which was traced to the living area of foreign aid workers. The outbreak was spread by _____. a. Tick bites b. Contaminated food c. Fecal water contamination d. Norovirus

c. Fecal water contamination

14. The most common opportunistic infection of AIDS patients is: a. Pneumonia b. Kaposi sarcoma c. TB d. Candidiasis

c. TB

Most common vector borne disease in eastern US is ______- a. entero fever b. Lyme c. malaria d. rabies

c. malaria

Richard Doll and Austin Bradford Hill

conducted groundbreaking studies on cigarette smoking and lung cancer in the 1950s

16. Recent increases in the number of cases of whooping cough have been linked to: a. Non medical exemptions b. Weaker vaccines c. Drug resistance d. A and B only

d. A and B only

Select the best answer: Disease...

does not occur at random

d. Women who are practicing physicians

dynamic. this is a changeable characteristic. new graduates are entering the practice and others are leaving

Population

is a group of people with a common characteristic

Non-response bias

low participation or differential participation of cases and control

If Relative Risk < 1

negative association; possibly protective

If you take the MCAT exam four times and you receive the same score all four times, we may conclude that the test is _____, but not necessarily_______.

reliable, valid

Ecological fallacy

when a suspected risk factor and disease occurrence are associated at the population level but not at the individual level

Relative Risk

"What is the ratio of the risk of disease in exposed individuals to the risk of disease in non-exposed individuals?" It is not expressed in negative numbers.

Calculate an infection rate given the following information. You are an infection control practitioner in a small rural hospital. You have had 12 MRSA cases in the past year and 76 pneumonia cases. During the year, you have had 14,038 patient visits. What was the MRSA infection rate per 1000 patient days?

# infections / # patient days 12 / 14,038 = 0.00085482 x 1000 = 0.85 MRSA infections per 1000 visits

What are common applications of Epidemiology?

*Describing and explaining disease occurrence in a community *Assisting in developing, prioritizing, and evaluating public health programs *Identifying risk factors and causes of disease *Evaluating the efficacy of various treatment options *Investigating disease outbreaks or epidemics *Assisting in health planning and health policy formulation *Understanding the natural history of diseases *Estimating individual risks of disease *Completing the clinical picture of disease.

Communities P and Q have equal age-adjusted mortality rates. Community P has a lower crude mortality rate than Q. One may conclude that:

- P has a younger population than Q

Mormons and Seventh-Day Adventists have lower-than-average age-adjusted death rates. The avoidance of alcohol and tobacco and the adherence to a healthful diet by members of these groups are factors:

- associated with the lower mortality rates but may not be causal factors

The purpose of a double-blind or double-masked study is to:

- avoid observer and subject bias

In a study of 500 cases of a disease and 500 controls, the suspected etiological factor is found in 400 of the cases and 100 of the controls. The absolute risk (incidence) of disease in persons with the factor is:

- cannot be computed from data given (You dont have outcome or incidence, so you cant calculate the absolute risk (incidence rate))

Overweight was recognized as a risk factor for a disease X (RR=4,0). The proportion of obese individuals in the population of interest is 50%. What is P AF (population attributable fraction) for smoking in the disease X

- cannot be determined on the basis of provided data

In a small pilot study, 12 women with endometrial cancer (cancer of the uterus) and 12 women with no apparent disease were contacted and asked whether they had ever used estrogen. Each woman with cancer was matched by age, race, weight and parity to a woman without disease. What kind of study is this?

- case-control

A study is conducted in which the rate of cigarette smoking and the prevalence of tuberculosis are assessed in the same population at the same time. Both are found to be high, and the conclusion is drawn that cigarette smoking is causally related to tuberculosis. Based on this study only, all of the following are true statements regarding this conclusion EXCEPT:

- it may be incorrect due to the ecologic fallacy

In a prospective study of a disease, the cohort originally selected consisted of:

- persons with the factor under investigation

Multiple disease outcomes can be studied, but only the risk factors defined and measured at the beginning of the study can be assessed.

- prospective cohort study

During a 3-month period, 9 cases of Hantavirus pulmonary syndrome are reported, and 3 of the cases die. Which of the following calculations would be 33%?

- the case fatality ratio

All of the following should be true of a disease for which screening is planned EXCEPT

- the disease should be rare

Epidemic refers to:

- the occurrence of illnesses of similar nature clearly in excess of the normal expectation for that population at that time

All of the following statements about multiple tests carried out in series are true EXCEPT:

- the specificity is lower than for tests carried out in parallel Parallel: inc sensitivity, dec specificity Series: dec sensitivity, inc specificity

In a diabetes detection program the screening level for blood sugar test A is set at 160 mg/100 ml and for test B at 130mg/100mg. This would mean that:

- the specificity of a test A is greater than that of test B

a. observational and experimental studies

-Observational: the investigator watches as subjects themselves choose which group they will be in (exposed or unexposed) -experimental: the investigator assigns participants to their exposure group

c. cohort and case-control studies

-a cohort study defines subjects according to their exposure level and follows them for a disease occurrence -a case control study defines cases of disease and controls and compares their exposure histories

briefly describe a cross-sectional study and indicate its main limitation

-a cross-sectional study examines the relationship between diseases and other variables at one particular time. subjects are commonly selected without regard to exposure or disease status. -its main limitation is that one cannot infer the temporal sequence between the exposure and disease

state the main difference between an age-specific rate and an age-adjusted rate

-age-specific rate is a rate that applies only to a particular age group -age-adjusted rate is a summary rate that accounts for the age differences between two populations

briefly describe an ecologic study and indicate its main limitation

-an ecologic study examines the rates of disease in relation to a population-level factor. -the lack of information about individuals leads to a limitation known as the ecological fallacy, which means that the assoicated observed on an aggregate level does not necessarily represent the associated that exists on the individual level.

a. low compliance

-design a simple protocol -enroll motivated and knowledgeable participants -maintain frequent contact with participants

a. individual and community trials

-individual: taretment is allocated to particular people -community: treatment is allocated to entire communities

In Australia on December 31, 1995, there were 4,494 dialysis patients and 4,209 transplant-dependent patients. At that time, there were approximately 9.3 million citizens in Australia. a. What is the prevalence rate for dialysis patients [1]?

0.00048

Part A. As an epidemiologist, you have been tasked with trying to understand more about the risk factors which influence the likelihood of having an MI (heart attack) in your local Broncoville residents. You want to know more about the relationship between MI, age, and smoking. 1. Calculate the incidence of having an MI if you are older than 50 [1]. 2.Calculate the incidence of having an MI if you are younger than 50 [2] 3. Calculate the relative risk of being older than 50 on MI [3]

0.14, 0.032, 4.39

In the previous question: A cohort study was conducted with 9,488 residents of Broncoville examining the impact of floor of residence on exposure to West Nile Virus (WNV). Residents were divided into those living on floors 4 or lower (5,080) or those living on floors 5 or higher (4,408). Blood was drawn for antibody testing to WNV. On the lower floors 47 persons were antibody positive and on the upper floors, 7 persons were antibody positive. Using the higher floors as the "exposed" group, set up a 2 x 2 table, showing the relative risk of residence on the upper floors compare with residence on the lower floors. You were asked to calculate the relative risk of developing WNV antibodies among residents who live on upper floors (5 or greater) versus those who live on lower floors (4 or less). Please interpret this answer using correct sentence formatting. What does the RR mean?

0.17 = 17% 100% - 17% = 83% The relative risk of developing WNV antibodies for those on the upper floors compared to those on the lower floors was 0.17. People who live on the upper floors are 83% less likely to develop WNV antibodies than people living on the lower floors. This suggests a strong protective effect of living on the upper floors.

In a recent retrospective cohort study in Lake Mantioc, Wisconsin, researchers found eight people have disappeared into the lake over the last 35 years and an additional new drowning has occurred under suspicious circumstances. Epidemiologists Ford and Hamill accessed patient records, autopsy reports, and interviewed surviving family members. The results are summarized in the table below: Drowned Did Not Drown Total Expert Swimmers 6 15 21 Unable to Swim 3 76 79 Total 9 91 100 What is the incidence rate of drowning for expert swimmers? Answers are rounded to two decimal places. If your answer is less than 1, place a 0 before the decimal (ie: 0.62)

0.29 A / (A + B) = 6 / (6 + 15) = 0.28571429 or 0.29

In a recent study of dental erosion in 5-year-old children, 202 healthy school-attending children were selected for study. The investigators recorded the erosion level on their maxillary deciduous incisors and whether or not their communities used fluoridated water. The results are summarized in the table below: Dental Erosion in 5-Year-Old Children Evidence of Erosion No Evidence of Erosion Total Fluoridated Area 46 (a) 30 (b) 76 Non-fluoridated Area 77 (c) 37 (d) 114 Total 123 67 190 What is the incidence rate of erosion for the fluoridated group of children? (You may assume their teeth were free of erosion at birth.)

0.61 new cases of dental erosion in the floridated area

0.68 new cases of dental erosion in the non-floridated area

Please answer the following questions in the space provided below; be as complete as possible to recieve full points. 1. Pick a specific disease (NOT malaria!!!!) and create an epidemiologic triad with the elements specific to your disease. 2. List one prevention measure that could be made to interrupt transmission of your disease at each point of the triad. 3. What is the significance of the epi triad?

1. Host, agent, environment (each with an example) 2. Invervention for each part of the triad example 3. Significance: All three components of the triad must be present for a disease to occur AND disease can be prevented/controlled at any point.

Broncoville has a population of 100,000. In 2011, there 1,000 deaths in the population from all causes. There were 300 cases of tuberculosis (TB) identified. In 2011, 110 people died of TB. What is the cause-specific mortality rate per 1,000 population?

1.10 TB deaths per 1,000 population in 2011

Of 2,872 persons who had received radiation treatment in childhood because of an enlarged thymus, cancer of the thyroid developed in 24 and a benign thyroid tumor developed in 52. A comparison group consisted of 5,055 children who had received no such treatment (brothers and sisters of the children who had received radiation treatment). During the follow-up period, none of the comparison group developed thyroid cancer, but benign thyroid tumors developed in 6. Calculate the relative risk for benign thyroid tumors:

15.3

Talbot and colleagues carried out a study of sudden unexpected death in women. Data on smoking history are shown in the following table. What are the odds that the controls smoke 1+ pack/day?

1:7 or (0.143)

Broncoville has a population of 356,797. In 2011, there 1,000 deaths in the population from all causes. What is the crude mortality rate per 1,000 population in 2011?

2.80 deaths per 1,000 population in 2011

Prospective Cohort

200 babies were followed from birth to age five to determine if those whose mothers smoked during pregnancy were more likely to have respiratory infections in the first five years of life than those whose mothers did not smoke during pregnancy. The findings supported the investigators' assumption that smoking during pregnancy increases the frequency of respiratory infections in young children.

248.37 PNA deaths per 1,000 PNA cases in 2014

A study starts with 5,000 people. Of these, 125 have the disease in question. What is the prevalence of disease per 1,000 people?

The results of a 10-year cohort study of smoking and coronary heart disease (CHD) are shown below: The incidence of CHD in smokers that can be attributed to smoking is:

27.5 per 1000

In a small pilot study, 12 women with uterine cancer and 12 with no apparent disease were contacted and asked whether they had ever used estrogen. Each woman with cancer was matched by age, race, weight, and parity to a woman without disease. 2. What is the estimated relative risk of cancer when analyzing this study as a matched-pairs study?

3.00

In a cohort study of smoking and lung cancer, the incidence of lung cancer among smokers was found to be 9/1,000 and the incidence among nonsmokers was 1/1,000. From another source we know that 45% of the total populations were smokers. The incidence of lung cancer attributable to smoking in the total population is:

3.6 per 1000

366.67 TB deaths per 1,000 population in 2011

Unmatch the pairs. What is the estimated relative risk of cancer when analyzing this study as an unmatched study design?

4.00

Broncoville is a very unsafe town. Its residents do not like wearing seatbelts and there is no law requiring seatbelts be worn. Approximately 50% of Broncoville residents refuse to wear a seat belt. Among those who wear seatbelts consistently, the incidence of death in motor vehicle accidents is 2.6 deaths per 10,000. The incidence of death from motor vehicle accidents among Broncoville residents who did not wear a seat belt is 10.6 deaths per 10,000. A. Calculate the relative risk RR of death among non-seatbelt users versus seatbelt users. [1] B. Calculate the attributable risk (AR) of not using a seatbelt on death in a motor vehicle accident. [2]

4.08, 60.63; Broncoville is a very unsafe town. Its residents do not like wearing seatbelts and there is no law requiring seatbelts be worn. Approximately 50% of Broncoville residents refuse to wear a seat belt. Among those who wear seatbelts consistently, the incidence of death in motor vehicle accidents is 2.6 deaths per 10,000. The incidence of death from motor vehicle accidents among Broncoville residents who did not wear a seat belt is 10.6 deaths per 10,000. A. Calculate the relative risk RR of death among non-seatbelt users versus seatbelt users. B. Calculate the attributable risk (AR) of not using a seatbelt on death in a motor vehicle accident. RR MVA death without seatbelt: 10.6 / 2.6 = 4.07692308 or 4.08 P = population = 50% or 0.5 RR = 4.08 AR = [P(RR-1)] / {[P(RR - 1)] + 1} x 100 AR = [0.5 (4.08 - 1)] / {[0.5 (4.08 -1)] + 1} x 100 AR = (1.54 / 2.54) x 100 AR = 0.60629921 x 100 = 60.63% of MVA deaths is attributed to not wearing a seatbelt.

Talbot and colleagues carried out a study of sudden unexpected death in women. Data on smoking history are shown in the following table. Calculate the matched-pairs odds ratio for these data.

4.5

Since April 2008, 810 persons infected with Salmonella Saintpaul with the same genetic fingerprint have been identified in 36 states and the District of Columbia. These were identified because clinical laboratories in all states send strains from ill persons to their state public health laboratory for characterization. The number of ill persons identified in each state is as follows: Arkansas (10 persons), Arizona (39), California (10), Colorado (8), Connecticut (4), Florida (1), Georgia (18), Idaho (3), Illinois (78), Indiana (11), Kansas (14), Kentucky (1), Maine (1), Maryland (25), Massachusetts (18), Michigan (4), Minnesota (2), Missouri (12), New Hampshire (3), Nevada (4), New Jersey (4), New Mexico (85), New York (25), North Carolina (5), Ohio (6), Oklahoma (19), Oregon (7), Pennsylvania (6), Rhode Island (3), Tennessee (6), Texas (342), Utah (2), Virginia (22), Vermont (1), Washington (4), Wisconsin (6), and the District of Columbia (1). What percent of the cases are from the state with the most cases?

42.22%

In Australia on December 31, 1995, there were 4,494 dialysis patients and 4,209 transplant-dependent patients. At that time, there were approximately 9.3 million citizens in Australia. b. What is the prevalence rate per million transplant-dependent patients [2]?

452.58

Case-Control study

50 patients recently diagnosed with hepatitis A were selected, along with 50 other subjects free of hepatitis A. The groups were then interviewed to determine if they had any body piercing or tattooing done within the past two months. To assure the groups were comparable; they were matched for age, gender, and race. The findings revealed that body piercing was more likely among the group with Hepatitis A than in those without the disease, after controlling for other factors.

n the previous question The incidence of myocardial infarction (MI) among nonsmokers in the population is 1 case per 1,000 persons. The incidence of myocardial infarction among smokers in the population is 4 cases per 1,000 persons. Assume 35% of the population smokes. You were asked to the calculate the attributable risk (AR) for smoking on MI. 1. Interpret your results using the correct sentence format. 2. What does this mean? 3. What public health message would you recommend?

51.22% of MI deaths is attributed to smoking. If you can convince the 35% of the population that smokes to stop, MI deaths would decrease by 51.22%. PH: smoking can contribute to MI

Bladder Cancer Rates in Cigarette Smokers and Nonsmokers Bladder Cancer Rates per 100,000 Men in Grand Junction, Colorado Cigarette smokers 58.0 Nonsmokers 6.4 What is the rate of bladder cancer for male cigarette smokers compared to male nonsmokers?

58 / 6.4 = 9.06

Talbot and colleagues carried out a study of sudden unexpected death in women. Data on smoking history are shown in the following table. Using data from the table unmatch the pairs and calculate an unmatched odds ratio.

6.3

Part B. You want to know if smoking is a confounder. Stratify (adjust) for smoking. 4. Calculate the relative risk of those who are over 50 and smoked [4] 5. Calculate the relative risk of those who are over 50 and did not smoke [5] 6. Is smoking a confounder? Answer YES or NO (all capitalized) [6]

6.56, 1.87, YES

In a recent retrospective cohort study in Lake Mantioc, Wisconsin, researchers found eight people have disappeared into the lake over the last 35 years and an additional new drowning has occurred under suspicious circumstances. Agents Ford and Hamill accessed patient records, autopsy reports, and interviewed surviving family members. The results are summarized in the table below: Drowned Did Not Drown Total Expert Swimmers 6 15 21 Unable to Swim 3 76 79 Total 9 91 100 What is the relative risk of drowning in Lake Mantioc if you are an expert swimmer? Answers are rounded to two decimal places. If your answer is less than 1, place a 0 before the decimal (ie: 0.62) Formula: [A / (A + B)] / [C / (C + D)]

7.52, Expert swimmers were 7.52 times more likely to drown in Lake Mantioc than people unable to swim.

A study starts with 4,875 healthy people. Over the next two years, 75 develop a disease. What is the incidence rate of disease over the study period?

75/(4875 x 2 years) =75/9750 years =0.00769/year or 7.69 per 1,000 person-years

Non-fatal heart attack Yes No Total HTN Yes 117 13,305 13,422 HTN No 125 106,416 106,541 242 119,721 119,963 What is the rate difference between those with the exposure of interest (Yes) versus those without the exposure of interest (No)? Be careful to round only at the very end of mathematical operations. Round to two decimal places.

754 cases of non-fatal heart attack per 100,000 population

In a cohort study of smoking and lung cancer, the incidence of lung cancer among smokers was found to be 9/1,000 and the incidence among nonsmokers was 1/1,000. From another source we know that 45% of the total populations were smokers. The proportion of the risk in the total population that is attributable to smoking is:

78.26%

8.13 deaths from PNA per 100,000 population in 2014

In a study of 500 cases of a disease and 500 controls, the suspected etiological factor is found in 400 of the cases and 100 of the controls. The incidence of disease in cases with the factor is:

80%

The results of a 10-year cohort study of smoking and coronary heart disease (CHD) are shown below: The proportion of the total incidence of CHD in smokers that is attributable to smoking is:

84.6%

This statistic describes a probability that someone selected at random from the population will have the disease in question. A. Prevalence B. Incidence C. Risk Ratio D. Risk Difference E. Attributable Fraction

Postive Predictive Value (PPV)

A / (A + B)

What would be an appropriate control group (s) for babies born at very low birth weight (<1500 grams)?

A and B, Babies born at normal birth weight (over 2500 grams), Babies born over 1500 grams

Reportable Disease

A disease required by law to be reported to the health officials

Epidemic

A greater than expected number of cases of disease

Information bias

A kind of bias which occurs as a result of measurement error in both exposure and disease. Examples include recall bias, interviewer bias, etc.

Relative Risk is:

A measure of association or relationship between the incidence in the exposed and that in the unexposed. Calculated by dividing the new onset cases by those not exposed to the factor

Odds Ratio

A measure of association used to quantify the strength of association between and exposure and an outcome. The number of cases and controls are arbitrary representations of the real population.

Interviewer bias

A physician says to his/her patient, "You've had chest pain in the past, right?"

Confidence Interval

A range of values thought to contain the true value a predetermined proportion of the time.

A state lawmaker has 18,651 adults in her district. 6,055 are female and 12,596 are male. What is the ratio of male to female employees? [1] What is the percent of males? [2] What is the percent of females? [3]

A state lawmaker has 18,651 adults in her district. 6,055 are female and 12,596 are male. Calculate the ratio of males to females. 12,596 / 6,055 = 2.08:1 Calculate the percent of the population that is males. 12,596 / 18,651 = 0.67535253 = 67.54 Calculate the percent of the population that is female. 6,055 / 18,651 = 0.32464747 = 32.46 67.54% + 32.46% = 100%

Nonresponse bias

A study following the health of elderly people and the associated lifestyles in the U.S. finds that they have less people in the 90+ age range returning for follow-up even though they are still alive.

Case Control

A study was undertaken to test the hypotheses that chewing tobacco increases the risk of stomach cancer. Detailed historical data on chewing tobacco use were collected from 400 subjects without stomach cancer and compared to the same historical data from subjects with stomach cancer. The results revealed that chewing tobacco was not a significant risk facor for stomach cancer.

Recall bias

A survey question asks a patient if they have ever taken flurosemide in their lifetime. The participant thinks he has taken it before, but isn't sure, so marks "yes"

Prevarication bias

A survey question put out by the American Heart Association asks participants if they smoke, and the participant who does smoke marks "no"

Short-Term Fluctuations

A temporal pattern that represent a relatively brief, unexpected increases in the frequency of a disease which commonly manifested in epidemics

Retrospective Cohort study

A total of 825 insulation workers employed between 1941 and 1944 were identified from the personnel records of three large insulation manufacturing plants in the SE United States in 1975. Between 1941 and 1975, 26 deaths from lung cancer were discovered among the workers. This was compared to 6 lung cancer deaths in a comparable group of 700 workers who were employed by the same companies but did not work with insulation during the same time period. The researchers calculated an increased risk of developing lung cancer among workers exposed to insulation versus those who were not exposed to insulation.

Retrospective Cohort

A total of 825 insulation workers employed between 1941 and 1944 were identified from the personnel records of three large insulation manufacturing plants in the southeastern U.S. in 1975. During the period 1941-1975, 26 deaths from lung cancer were discovered among the workers. Only six lung cancer deaths, however, were reported among a comparable group of 700 coworkers who did not work with insulation during the same time period. The investigators had postulated that exposure to the insulation material increases the risk of lung cancer.

Researchers studying the association of diabetes with hypertension have decided to restrict their study population to non-obese patients in order to reduce the confounding effect of obesity on hypertension. What are some limitations associated with this restriction?

A. All of the above, Reduces generalizability B. Increases the level of difficulty of finding study subjects C. Eliminates the opportunity to assess potential interactions between obese patients and hypertension

A. OR = 5.44 Cases were 5.44 times more likely to NOT consistently use insect repellant than controls. Lack of consistent insect repellant may increase the risk for contracting malaria when visiting tropical countries.

During the 20th century, the U.S.experienced a change in leading causes of death: A. from primarily infectious diseases to primarily chronic diseases. B. From primarily chronic diseases to infectious diseases C. Due to increases in infant mortality and decreases in diseases affecting the elderly. D. Due to decreases in infant mortality and decreases in diseases affecting the elderly.

A. from primarily infectious diseases to primarily chronic diseases.

Person Variables

Age Sex Race/Ethnicity SES Occupation Education Religion Marital Status Health Status Immunization Status Lifestyle or Behavioral Practice Environmental exposure

Issues with a cohort study may include

All of the above

Source(s) of participants for case-control studies include

All of the above

The theory that there IS an association between the exposure and the outcome.

Alternate hypothesis

Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking. This measure is an example of:

An attributable risk

Pandemic

An epidemic spread over a wide geographic area

Five years after the introduction of a vigorous detection program, the prevalence of diabetes mellitus was found to be greater than in the year prior to the introduction of the program. Which of the following are possible reasons?

An increase in previously undetected cases

This statistic is used to estimate the risk of acquiring a disease. It may be measured as a rate or as a proportion. A. Prevalence B. Incidence C. Risk Ratio D. Risk Difference E. Attributable Fraction

Investigators are studying employees at a bus company to test their hypothesis that occupational stress causes high blood pressure. Two major groups of employees are of interest: bus drivers and office workers in the same salary range. The investigators measure the blood pressure of all bus drivers and of a group of office workers matched to the bus drivers on age, sex, ethnicity and length of employment. The mean blood pressure of the drivers is higher than that of the office workers and the investigators conclude that stress causes high blood pressure. Is this: A. Experimental B. Observational If B, is the study: A. Cross-sectional B. Case control C. Retrospective cohort D. Prospective cohort

B A

One hundred persons with hepatitis A and 100 healthy neighbors were questioned regarding their history of eating raw clams or oysters in the preceding 3 months. Is this: A. Experimental B. Observational If B, is the study: A. Cross-sectional B. Case control C. Retrospective cohort D. Prospective cohort

B B

Some studies have identified a behavior pattern called Type A which they have associated with myocardial infarction. Type A behavior was assessed for a group of men in a post-MI rehab program. All men not falling into the Type A group were classified as Type B. Type A and Type B men were followed for five years to assess MI recurrence rates. Is this: A. Experimental B. Observational If B, is the study: A. Cross-sectional B. Case control C. Retrospective cohort D. Prospective cohort

B D

When setting up a 2 x 2 table for a case-control study (below), the cases/controls with the disease should be placed at (A or B) [1] and the exposure/lack of exposure should be placed at (A or B) [2]. Use only uppercase letters.

B, A

A researcher is interested in recording the number of individuals in a particular geographic region who have a common cold at some point during the month of February 2001. Which of the following measures of morbidity would be most appropriate in answering this question? A. Point Prevalence B. Period prevalence C. Cumulative Incidence D. Incidence Density

B. Period prevalence

One of the fundamental premises underlying the study of epidemiology is: A. disease, illness and ill health are randomly distributed in a population. B. disease, illness and ill health are not randomly distributed in a population. C. Disease, illness and ill health are only randomly distributed in large populations. D. Disease, illness and ill health are very rarely distributed in large populations.

B. disease, illness and ill health are not randomly distributed in a population.

It is assumed that diseases can be transmitted directly or indirectly. A vector such as a mosquito is an example of... A. direct disease transmission B. indirect disease transmission C. single exposure D. common vehicle exposure

B. indirect disease transmission

During the 19thcentury, John Snow: A. proved his miasmatic theory of disease using shoe leather epidemiology. B. proved that cholera was spread through contaminated water by conducting natural experiments. C. was the first anesthesiologist to use chloroform on a woman in labor. D. hypothesized that cholera was primarily due to overcrowded conditions and malnutrition.

B. proved that cholera was spread through contaminated water by conducting natural experiments.

Select all that apply: In order for a variable to be a confounder, it must:

Be associated with the exposure of interest Cannot be an intermediate step in the causal path between exposure and disease Be a risk factor for the disease

A study to assess the association of diabetes and smoking compares a group of hospitalized individuals with diabetes and a group of volunteer individuals without diabetes that are employees of the same hospital where the cases were identified. The results from this study reported, for the first time in the literature, a strong association between diabetes and smoking. The magnitude of this association is likely to be due to (Check all that apply):

Berkson's bias, Non-response bias

Cohort studies are most appropriate for

Both b and c are correct, Common exposures, Looking at multiple effects of a single exposure

This statistic describes the excess in risk associated with an exposure in relative terms. When it is 1, there is no additional risk associated with the exposure. A. Prevalence B. Incidence C. Risk Ratio D. Risk Difference E. Attributable Fraction

A researcher is interested in knowing how many new cases of the measles developed at St. Theresa's Elementary School in April 2001. Assuming that no children enrolled during that month, and no children moved during that month (all children were followed for the entire month), which measure of morbidity would be most appropriate in answering this question? A. Prevalence B. Point prevalence C. Cumulative Incidence D. Incidence Density

C. Cumulative Incidence

Which of the following is not a primary requirement for conducting screening for disease control A. Prevalence of the disease should be high in the population under study B. There should be a favorable prognosis for early treatment of the disease C. The government should fund the program. D. The disease should be serious

C. The government should fund the program.

The attack rate in susceptible people who have been exposed to a primary case is referred to as A. The attack rate B. The post primary attack rate C. The secondary attack rate D. The person-to-person attack rate

C. The secondary attack rate

The resistance of a population to an attack by a disease to which a large proportion of the members of the group are immune is referred to as... A. group resistance B. population immunogenesis C. herd immunity D. the Panum Effect

C. herd immunity

Relative Risk

Calculated by dividing the incidence rate of those exposed to a factor by the incidence rate of those not exposed to the factor

Compares two groups to identify probable causes of a rare disease

Case-Control

You are investigating an outbreak of RSV in Broncoville. The outbreak is primarily occurring among children ages 1 - 4 years. Two day care centers serve Broncoville. The first day care center, Happy Child, has 33 children ages 1 - 4 enrolled. The second day care, Little Heathens, has 63 children aged 1 - 4 years enrolled. There are 12 cases of RSV in children aged 1 - 4 enrolled in Happy Child and six cases of RSV in children aged 1 - 4 enrolled in Little Heathens. Develop a 2 x 2 table. A. Calculate the RSV cases per 100 children enrolled in Happy Child [1] B. Calculate the RSV cases per 100 children enrolled in Little Heathens [2] C. What is the relative risk of developing RSV if a child is enrolled at Happy Child day care versus Little Heathens day care? [3] Enter only numbers into your answer. Round to two decimal places after completing mathematical operations. Save your answer to the RR calculation for the next question on the exam.

You are investigating an outbreak of RSV in Broncoville. The outbreak is primarily occurring among children ages 1 - 4 years. Two day care centers serve Broncoville. The first day care center, Happy Child, has 33 children ages 1 - 4 enrolled. The second day care, Little Heathens, has 63 children aged 1 - 4 years enrolled. There are 12 cases of RSV in children aged 1 - 4 enrolled in Happy Child and six cases of RSV in children aged 1 - 4 enrolled in Little Heathens. Develop a 2 x 2 table. Calculate the RSV cases per 100 children enrolled in Happy Child Calculate the RSV cases per 100 children enrolled in Little Heathens What is the relative risk of developing RSV if a child is enrolled at Happy Child day care versus Little Heathens day care? Happy Child A / (A+ B) x 100 = 12 / (33) = 0.36363636 x 100 = 36.36 Little Heathens C / (C+ D) x 100 = 6 / (63) = 0.0952381 x 100 = 9.52 RR = 0.36363636 / 0.0952381 = 3.82

You are completing a retrospective cohort study of 52,999 patients who take a lisinopril, an angiotensin converting enzyme (ACE) inhibitor, prescribed for high blood pressure. All of your study subjects have been on the medication for at least one year. A common side effect of this medication is chronic cough. After completing the survey you find, 24,877 patients claim they developed the cough at some point in the past year, but it has resolved. 16,322 patients describe new onset cough at the time of the survey (now). 1. What is the incidence of the side effect [1] 2 What is the prevalence of this side effect in the population [2]

You do a survey of 52,999 patients who take a lisinopril, and angiotensin converting enzyme (ACE) inhibitor, for high blood pressure. All of these patients have been on the medication for at least one year. A common side effect of this medication is chronic cough. 24,877 patients claim they developed the cough at some point in the past year, but it has resolved. 16,322 patients describe new onset cough at the time of the survey (now). 1. What is the incidence of the side effect [1] New cases / population 16,322 / 52,999 = 0.30796805 = 0.31 2. What is the prevalence of this side effect in the population [2] Total cases / population (24, 877 + 16,322) / 52,999 = 0.77735429 = 0.78

What do Typhus, West Nile, and Malaria have in common?

ZOONOTIC

placebo and sham procedure

a placebo is an inactive substance. a sham is a bogus predecure that is designed to resemble a legitimate one.

randomization

a process by which the investigator assigns subjects to the treatment and comparison groups. subjects have an equal chance of being assigned to either the treatment or comparison group

Confounding factor

a third variable which, independent of exposure, is a risk factor for the disease

43. What is the secondary antibody response? a. Antigen-stimulated B cells multiply and differentiate b. Memory B cells transform into antibody secreting cells c. Phagocyte encounters a pathogen or product & engulfs it d. Inflammatory response leads to redness, swelling & localized heat

a. Antigen-stimulated B cells multiply and differentiate

49. Diptheria infection often leads to pseudomembrane formation, a type of _____ that _____. a. Biofilm, prevents immune attack b. Infection, often leads to death c. Abcesses, pathogen spread d. Consortia, immune attack

a. Biofilm, prevents immune attack

21. Which of the following combinations would you expect to find in an individual who has been diagnosed with AIDS? a. CD4 cell count below 200 and high viral load b. Low levels of HIV antibodies and low viral load c. Low viral load and high levels of Gp120 antibodies d. High CD4 count and high viral load

a. CD4 cell count below 200 and high viral load

9. Pronounced seasonality in the incidence of a disease is often indicative of a. Certain modes of transmission b. The presence of carriers c. A zoonotic infection d. A seasonal reservoir

a. Certain modes of transmission

36. Microbes are sometimes used in sewage pretreatment processes to _____. a. Convert toxic substances to less toxic forms. b. Degrade larger objects that cannot be removed by screens c. Introduce competitive microbes info effluent that is filled with pathogenic organims d. All of the above

a. Convert toxic substances to less toxic forms.

28. Serious acute cases of diphtheria are treated with antibiotics and _____. a. Diphtheria antitoxin b. Diphtheria toxin c. Diphtheria toxoid d. All of the above

a. Diphtheria antitoxin

35. Coliforms in a water sample indicate _____ contamination. a. Fecal b. Industrial or chemical c. Arthropod d. All of the above

a. Fecal

11. The type of genetic change that is feared may lead to a species jump and a new flu pandemic is: a. Genetic shift b. Sero conversion c. Genetic drift d. Back mutation

a. Genetic shift

37. With increased levels of oxidizable materials, the biochemical oxygen demand (BOD) will a. Increase b. Decrease c. Remain the same d. Drop then rise

a. Increase

6. E.coli is an indicator bacterium for water testing because it _______. a. Is found in human and animal fecal waste b. Is easily grown c. Ferments lactose d. Is widely studied

a. Is found in human and animal fecal waste

2. Water testing for pathogens makes use of ____ found in human and animal feces. Indicator organisms a. Parasites b. Nosocomial infection c. Direct contact infection d. Cross contamination infection

a. Parasites

10. Mad cow disease is caused by a transmissible ______. Infection can also be caused by: a. Virus, aerosol droplet b. Protein, contaminated feed c. Direct contact infection, genetic factors d. Fungus, contaminated feed

a. Virus, aerosol droplet

4. Pickling is a type of food preservation utilizing ______. a. Weak acids b. Basic substances c. Lyophilization d. Irradiation

a. Weak acids

Streptococcus pneumoniae Select one: a. is surrounded by a polysaccaride capsule that makes phagocytosis very difficult. b. is the only causative agent of pneumonia. c. can only cause lung infections d. is unlikely to infect immunocompromised patients

a. is surrounded by a polysaccaride capsule that makes phagocytosis very difficult.

Of 2872 persons who had received radiation treatment in childhood because of enlarged thymus, cancer of the thyroid developed in 24 and benign thyroid tumor developed in 52. A comparison group consisted of 5055 children who had received no such treatment (brothers and sisters of those children who had received radiation treatment). During the follow up period, none of the comparison group developed thyroid cancer, but benign thyroid tumors developed in 6. Calculate the relative risk for benign thyroid tumors:

a/(a+b) / c/(c+d) = 15,25

To calculate an odds ratio:

ad/bc

Random error, or sampling variability can be reduced by

all of the above, an increase in sample size, a change in study design, improving instrumentation

Disease Determinants

are factors that either cause a healthy person to become sick or cause a sick person to recover

6. The onset of a given epidemic is indicated by a sharp rise in the number of cases reported daily over a brief interval. This indicates that the mode of transmission is ______. a. Host to host b. A common source c. Insect vector d. Mechanical vector

b. A common source

30. Which of the following does NOT explain the increase seen in Whooping Cough in the recent decades? a. The use of acellular versus whole cell vaccine b. Better diagnostic and reporting technology c. More people are choosing not to vaccinate d. Increasing incidence of resistant strains

b. Better diagnostic and reporting technology

41. To reduce further the possibility of biological contamination, most treatment plants treat the effulent with ____. a. Fluorine b. Chlorine c. Ozone d. Extreme heat

b. Chlorine

1. Oocysts of this protozoan are resistant to chlorination treatments of municipal water supplies. a. Coliforms b. Cryptosporidium c. Valley fever d. Botulinum

b. Cryptosporidium

42. Effulent water is wastewater ______. a. Discharged from the pharmaceutical, plastics, and petrochemical industries b. Discharged from the wastewater treatment facility c. That has undergone anoxic secondary wastewater treatment d. That is imported to the wastewater treatment facility for treatment

b. Discharged from the wastewater treatment facility

The organism that causes giardiasis is a ______. a. Gram-negative spirochete b. Flagellated protozoan c. Retrovirus d. Type of yeast

b. Flagellated protozoan

7. Which of the following is an example of herd immunity? a. Brucellosis is no longer found in farm animals in the United States. b. If 70% of the population is immunized against polio, the disease will die off. c. Federal law requires that all cattle not immune to anthrax be destroyed. d. Most cows do not get Mad Cow disease.

b. If 70% of the population is immunized against polio, the disease will die off.

27. Tuberculoid Hansen's disease is caused by the pathogen ____. a. Listeria monocytogenes b. Mycobacterium leprae c. Mycobacterium tuberculosis d. All of the above

b. Mycobacterium leprae

8. A large number of cases of a particular disease observed in a relatively short period of time in an area that previously experienced only sporadic cases of the disease is known as a(n): a. Pandemic b. Outbreak c. Endemic d. Zoonosis

b. Outbreak

Which of the following is an obligate intra cellular pathogen. Select one: a. Streptococus b. Ricksettia c. plasmodium d. a, b, c

b. Ricksettia

13. The innate immune system responds to seasonal flu antigens. The adaptive immune system responds to ancient antigens. a. Ancient, seasonal flu b. Seasonal flu, ancient c. Bacterial specific, viral specific d. Viral specific, bacterial specific

b. Seasonal flu, ancient

In the DTaP vaccine, 'a' stands for Select one: a. attenuated b. acellular c. antitoxin d. antibody

b. acellular

A factor associated with increased whooping cough is ________. a. overuse of antibiotics b. acellular vaccines c. whole agent vaccines d. drug resistance

b. acellular vaccines

H. pylori infection greatly reduced due to a. changes in diet b. antibiotics c. horizontal gene transfer d. bariatric surgery

b. antibiotics

Rickettsias are small ______ that have strict intracellular existence in vertebrates a. viruses b. bacteria c. protists d. fungi

b. bacteria

ELISA uses ___ to detect human proteins. a. radioactivity b. enzyme conjugated anti-human antibodies c. fluorescent antibodies d. flow cytometry

b. enzyme conjugated anti-human antibodies

HIV rapid tests are confirmed using western or immuno blotting. this works by veryifying __________ a. HIV viral load b. human antibodies against multiple HIV antigens c. CD4 cell counts d. sero positive status

b. human antibodies against multiple HIV antigens

Penicillin antibiotics have high therapeutic index bc a. semisynthetic b. human cells dont have PG c. inhibit protein synthesis d. they have long half life

b. human cells dont have PG

Colistin-resistant bacteria_______. a. produce exoenzyme b. prevent drug from binding c. pump colistin d. none of the above.

b. prevent drug from binding

Former president Carter had treatment a. increasing all cell division b. taking the brakes off T cells c. promoting agngiogenesis d. stimulating antibodies

b. taking the brakes off T cells

In order for a variable to be an effect modifier, it must:

be a variable in the causal pathway between exposure and disease

State Vital Statistics

births, deaths, marriages, divorces

b. risk difference and population risk difference

both provided information on the absolute effect of the exposure or the excess risk of disease. -risk difference gives the number of cases of disease among the exposed that may be attributable to the exposure -population risk difference gives the number of cases of disease in the total population that may be attributable to the exposure

b. retrospective cohort and prospective cohort studies

both the exposures and outcomes have already occureed at the state of a retrospective cohort study, the outcomes have not yet developed at the statrt of a prospective cohort sutdy. -retrospective cohort study investigates prior outcomes -prospective cohort study investigates future ones

Which one of the following does not pertain to herd immunity? a. In most cases, vaccinations are key to achieving her immunity. b. Herd immunity is related to preventing transmission among susceptible members of the population. c. 100% of immunization is necessary to control a disease in a population d. Diseases can essentially be eradiated in populations by immunizing enough people.

c. 100% of immunization is necessary to control a disease in a population

39. Vinegar is actually dilute _____. a. Hydrochloric acid b. Sulfuric acid c. Acetic acid d. Phosphoric acid

c. Acetic acid

29. Which of the following is NOT true regarding diphtheria? a. The associated toxin inhibits protein synthesis b. C. diphtheria can be treated with antibiotics & antitoxin c. C. diphtheria is extremely infectious but the toxin is not very potent d. An infection can cause a diagnostic pseudomembrane

c. C. diphtheria is extremely infectious but the toxin is not very potent

38. Which product of anoxic/anerobic sewage treatment can be used to heat and power an entire water treatment facility? a. CO2 b. H2 c. CH4 d. O2

c. CH4

8. Which of the following is NOT true about tuberculosis? a. Mycobacterial resistance to isoniazid & other drugs is increasing. b. Mycobacterium can infect & grow in macrophages. c. Cell-mediated immunity is effective in the short term but doesn't last in the long-term d. The disease agent infects about 1/3 of the world's population.

c. Cell-mediated immunity is effective in the short term but doesn't last in the long-term

26. Whooping cough is frequently observed in a. Elderly residents of nursing homes b. Individuals with compromised immunity c. Children under 19 years of age d. Cancer patients

c. Children under 19 years of age

28. Which of the following combinations of disease and pathogens is INCORRECT? a. Lyme disease & Borrellia burgdorferi b. Rocky Mountain spotted fever & Rickettsia c. Cirrhosis and Helicobacter pylori d. Hepatitis & HCV

c. Cirrhosis and Helicobacter pylori

Which one of the following is NOT true in regards to EIA? a. EIA is a relatively cheap, fast, & sensitive way to screen for infection. b. EIA measures the patient's antibody quantity against a pathogen's antigen. c. Conserved EIA is the most effective type of EIA. d. For direct & indirect EIA, color positively correlates with target molecule being screened.

c. Conserved EIA is the most effective type of EIA.

50. Which of the following is NOT a virulence factors of Staphylococcus? a. Enzymes that lyse WBCs (and lead to lots of pus.) b. Enzyme (Coagulase) that causes essentially a clot (fibrin) to protect the pathogen c. Exotoxin that functions as superantigen d. Displays novel proteins on cell wall unrecognized by PRR's

c. Exotoxin that functions as superantigen

HAART is commonly used to treat infections due to a. drug resistant strains of bacteria b. M. tuberculosis c. HIV d. s. aureus

c. HIV

37. The following disease can be controlled by immunization except: a. pertussis b. smallpox c. HIV/AIDS d. Rubella

c. HIV/AIDS

22. Pneumocystis pneumonia and Kaposi's sarcoma were, until the 1980s, rare conditions. Reports of clusters of these infections in ____ was the first piece of evidence of ____ in the US.. a. Sex workers, HPV/cervical cancer b. Heterosexual men, herpes c. Homosexual men, AIDS d. Homosexual women, AIDS

c. Homosexual men, AIDS

35. Which one of the following classed of immunoglobulin is often important in response to respiratory infections of the mucosal membranes? a. IgG b. IgA c. IgE d. IgM

c. IgE

Which of the following is not an emerging disease in the United States? a. West Nile Virus b. Chagas c. Influenza d. Chickunguna

c. Influenza

43. Which of the following bacterial pathogens is found in both aquatic environments and is commonly present in air conditioning systems? a. Enterobacter aerogenes b. Klebsiella pneumonia c. Legionella pneumonphilia d. Vibrio cholera

c. Legionella pneumonphilia

31. Pus formation in the skin lesions caused by Staphylococcus aureus infections is, in part, due to the production of ______. a. Coagulase b. Hemolysins c. Leucocidin d. Catalase

c. Leucocidin

34. In the US there are currently two endemic tick borne dieases, Rocky Mountain Spotted Fever and ______? a. Hansen's Disease b. West Nile Virus c. Lyme's Disease d. Malaria

c. Lyme's Disease

40. Most common-source, individual, foodborne botulism outbreaks are due to consumption of _____. a. Honey b. Dairy products c. Nonacid, home-canned vegeatables d. Egg and meat salads

c. Nonacid, home-canned vegeatables

44. Prions are _____. a. Proteins, presumably of host origin b. Carbohydrates, presumably of host origin c. Proteins, presumably of nonhost origin d. Carbohydrates, presumably of nonhost origin

c. Proteins, presumably of nonhost origin

12. Maps of the world for malaria and the type of hemoglobin that causes sickle cell anemia ______. a. Change drastically b. Are unavailable c. Roughly overlap d. Are unrelated

c. Roughly overlap

3. __________ diseases primarily infect animals but are occasionally transmitted to humans. a. Nosocomial infections b. Vector infections c. Zoonotic d. Common source outbreaks

c. Zoonotic

Avastin binds and inhibits a. macrophage b. lysosomes c. vascular endothelial growth factor d. mitosis

c. vascular endothelial growth factor

Hep C is a latent ________ infection that can lead to _______. a. bacterial, blood poisoning b. viral, cervical cancer c. viral, cancer d. bacterial, sepsis

c. viral, cancer

A marked seasonability disease is often indicative of a. blood borne b. presence of carriers c. zoonotic infection d. common source infection

c. zoonotic infection

John Snow

conducted one of the first observational studies in neighborhoods of 19th-century london and discovered that contaminated drinking water was the cause for cholera

James Lind

condued one of the earliest experimental studies on the treatment of scurvy among sailors.

What measure: The percentage of freshman girls who become pregnant over the course of their high school years

cumulative incidence

what measure: the lifetime risk of breast cancer

cumulative incidence

What do "Rapid" tests for Strep throat, HIV & pregnancy in humans have in common? a. Antibodies b. They use radioactive iodine c. They are colorimetric tests d. A & C e. A, B & C

d. A & C

23. Which of the following diseases is streptococcal in origin? a. Impetigo b. Scarlet fever c. Rheumatic fever d. A, b, and c

d. A, b, and c

45. The principle behind sugar or salt preservation is to _______. a. Introduce a mechanical barrier to microbial invasion b. Reduce water availabiltu (aw) c. Introduce a microbiocide in anticipation of contaminating bacteria or fungi d. Accomplish all of the above, depending on the food being preserved.

d. Accomplish all of the above, depending on the food being preserved.

20. Rheumatic fever is ______. a. An autoimmune disease b. A post-streptococcal disease c. Triggered by cell-surface antigens on Streptococcus pyogenes cells that are similar to heart valve and joint antigens d. All of the above

d. All of the above

24. Which of the following is TRUE about tuberculosis? a. Good chemotherapy is available, mycobacterial drug resistance is increasing. b. Not everyone exposed gets infected c. The disease agent infects about one-third of the world's population. d. All of the above

d. All of the above

32. Malaria is _______. a. The most common cause of death due to infectious disease worldwide b. Prevented and treated with chloroquine and closely related drugs c. Controlled primarily by controlling the mosquito vector d. All of the above

d. All of the above

5. Hospital and nursing home patients are susceptible to serious infections because _________. a. Many patients have low resistance to infectious diseases b. The use of antibiotics selects for antibiotic-resistant organisms c. Many diverse human reservoirs are present d. All of the above

d. All of the above

8. Water and food-borne disease can be controlled by ______. a. Proper sewage disposal b. Pasteurization c. Water treatment d. All of the above

d. All of the above

4. Giardia colonizes the gut of animals, including humans, by _____. a. Forming a psuedomembrane b. Destroying microvilli c. Attachment by pili d. Attachment by ventral sucking disc

d. Attachment by ventral sucking disc

46. Pattern recognition receptors were first recognized in _________and called _________ a. Mice, PAMPs b. Rabbits, Lipids c. Fruit flies, toll receptors d. Chimpanzees, PRPs

d. Chimpanzees, PRPs

30. The most common infectious diseases(s) is/are _____. a. Gonorrhea b. Influenza c. Hepatitis d. Colds

d. Colds

21. Currently, HIV infections are treated with combinations of antiretroviral drugs and there is no protective vaccine on the horizon. Ultimately, this is due to: a. Unprotected sex & IV drug use b. reverse transcriptase error rate c. compromised host transcription d. HIV's ability to kill T cells

d. HIV's ability to kill T cells

47. Staphylococcus aureus is a common foodborne disease because it ______. a. Grows on many common foods b. Is a member of the normal flora on some humans that work with food processing c. Produces several heat-stable enterotoxins d. Is all of the above

d. Is all of the above

2. A disease that is present in unusually high numbers throughout the world is called a(n): a. Endemic b. Epidemic c. Sporadic d. Pandemic

d. Pandemic

49. Which one of the following is NOT true regarding Streptococcus pyogenes? a. The causative agent of 'strep throat' b. Can cause Scarlet fever, impetigo, & has been known to eat flesh c. Can produce exotoxin that functions as a superantigen d. Resistant to most antibiotics

d. Resistant to most antibiotics

Extensively drug resistant Tuberculosis (XDRTB) is considered_________________. Select one: a. a MDRO (a multi drug resistant organism) b. a secondary infection c. a re-emerging pathogen d. a and c

d. a and c

Factors that have led to an increase in nosocomical, or hospital-acquired infections, include ____ . Select one: a. lots of sick people b. antibiotic over use c. invasive medical devices d. a, b and c

d. a, b and c

Which of the following is/are reasons why a tick bite doesn't always lead to Lyme infection Select one: a. tick wasn't infected b. tick fed for a short time c. no bull's eye rash d. a, b, c e. a and b

d. a, b, c

33. An endemic disease: a. is constantly present in the population b. has a low incidence in the population c. is persistent in the population due to presence of reservoirs d. all of the above

d. all of the above

H. pylori infection can lead to a. UTI b. TB c. upper resp. infection d. digestive system ulcers

d. digestive system ulcers

Rapid/ELISA test for HIV detects a. the virus b. viral proteins c. reverse transcriptase error rate d. human antibodies against HIV

d. human antibodies against HIV

c. fixed and dynamic population

dynamic is defined by a changeable state or condition, membership is transitory. fixed is defined by a life event, membership is permanant.

a. People who live in New York City

dynamic. this is a changeable condition, people are continually entering and leaving the city

7. Lower levels of death from infectious diseasesm in the Western/developed world are due to a. Better general health b. Vaccinations c. Water quality standards d. Animal hygiene e. All of the above

e. All of the above

29. The DTaP vaccine contains heat-killed bordetella pertussis cells a. Purified bacterial DNA b. Attenuated provirus c. Bordetella pertussis protein d. Diphtheria toxoid e. C and D

e. C and D

When interpreting an odds ratio one explains differences in the likelihood of

exposure

b. when calculating the incidence rate of a disease, it is necessary to follow all subjects for the same length of time

false

c. if the incidence rate of a very serious disease is75/100,000 person-years and the prevalence of this disease in the population is 25/100,000, then the average duration of this disease must be 3 years.

false

b. Men who had coronary bypass surgery as of 2011

fixed. this is a permanent characteristic, once a man has the surgery, he is part of the group forever

c. Children who were vaccinated against polio in 1955

fixed. this is also a permanent characteristic

Website for problems 1-6 (key attached)

http://www.sjsu.edu/faculty/gerstman/hs161/quiz02s1.PDF

what measure: the number of live born babies who die of SIDS during the first year of life per 100,000 baby-years of follow-up

incidence rate

equipoise

is a stae of mind characterized by a genuine uncertainty about the appropriate course of action--that is, to give or withhold a particular treatment.

Disease Control

is teh ultimate aim of epidemiology and refers to the reduction or elimination of disease occurance.

lead time

is the amount of time that the diagnosis of disease is advanced by screening

Epidemiology

is the study of the distribution and determinants of disease frequency in the human populations and the application of this study to control health problems.

Predictive value of a positive test

it is a way to measure a screening program's feasibility. it is the proportion of individuals with a positive test who have preclinical disease

Describe the three types of bias that must be considered when evaluating the results of a screening program

lead time bias: means that survival among screened individuals may appear longer than that for non screened individuals just because they were diagnosed earlier. length bias sampling: survival among screened individuals may be longer than noynscreened individuals because screening tends to identify less aggressive forms of disease. volunteer bias: only occurs in observational screening. means that people who get screened tend to have different characteristics than those who do not get screened and may be related to survival

Validity

measuring what you intend to measure - or getting the correct result

In which two divergent directions has modern epidemiolgoic research expanded?

modern epidemiology examines risk factors from the molecular level to the societal level

If Relative Risk = 1

no association

Select all that apply: Which of these is a determinant of disease

occupational exposure, socio-political factor, aging

run-in period

occurs before enrollment and randomization to determine which participants are able to comply with the study regimen.

Epidemiology studies disease occurrence among

populations

If Relative Risk > 1

positive association; possibly causal

what measure: the percentage of infants weighing less than 2,500 grams at birth

prevalence

what measure: the percentage of senior boys who are fathers at the time of graduation

prevalence

Behavioral Risk Factor Surveillance System

prevalence of chronic diseases

a. Prevalence and incidence

prevalence quantifies existing cases, incidence quantifies new cases

The ultimate goal of epidemiology is to [x] and [y] disease in populations

prevent and control

Public Health

public health is a multidisciplinary field whose goal is to promote the health of populations through organized community efforts

Disease Frequency

quantifies how often a disease arises in a population

Select all that apply: Aspects of "person" are measured using numerous things such as

race or ethnicity, gender, occupation, age,

Census

race, gender, age, marital status

Which of these is not a determinant of disease?

random event

Disease Distribution

refers to the pattern of disease according to the characteristics of person, place, and time

Morbidity

relating to or characteristic of a disease or illness

If you take an exam five times and you receive the same score all five times, we may conclude that the test is _____, but not necessarily_______.

reliable, valid

Reliability

repeatability - able to obtain the same result over and over again

In a study designed to estimate the prevalence of hypotension (low blood pressure) among adults in an inner-city community, a sample of residents is selected for examination. Which of the following sampling methods is least likely to introduce bias?

residents living in a random selection of addresses from the street directory of the community

what types of disease are appropriate for screening?

serious diseases with fairly long and prevalent detectable preclinical phases for which treatment is more effective at earlier stages

b. incidence rate and cumulative incidence

similarity: both quantify the number of new cases of disease that develop in a population at risk during a specified period of time. difference: incidence rate is a true rate that directly integrates person-time of observation into the denominator and cumulative incidence is a proportion whose denominator is the population at risk at the start of the observation period.

Specificity

specificity is also a measure of a screening tests validity. the complement of sensitivity, it is the probability that a screening test classifies as negative those who do not have preclinical disease

Case-control study design

start the study with subjects who have already been identified as having the outcome/disease of interest

Experimental study design

subjects are randomized by the researchers

John Graunt

summarized the patterns of mortality in 17th-century london and discovered the regularity of deaths and births

Bias

systematic error usually introduced by the researcher

Misclassification

systematic tendency for individuals to be erroneously placed in the wrong exposure/outcome categories

reference population

the group of people to whom the study results may be applied or generalized

Attack rate

the measure of the number of people who become ill following an exposure, usually measured over a short time frame

single-masked study

the study subject does not know whether he or she is in the treatment or comparison group. single-blind study

a. incidence rate ratio and incidence rate difference

they are both ways to compare measures of disease frequency in order to assess the impact of an exposure on a disease. -the ratio measure gives information on the strength of the relationship between an exposure and disease -the difference measure describes the excess number of cases of disease that are associated with the exposure

How are the many subspecialties of modern epidemiology typically defined?

they are defined in terms of the exposure (environmental exposures) the disease (cancer) and the population being studied (the elderly)

Why are experimental studies difficult to conduct?

they are expensive to conduct, physicians and patients may be reluctant to participate, and a state of equipoise must exist

What are the main objectives of epidemiology?

they are to study the natural course of disease, to determine the extent of disease in a population, to identify patterns and trends in disease occurence, to identify the causes of disease, and to evaluate the effectiveness of measures that prevent and treat disease.

How do epidemiologists quantify the disease frequency in a population?

they quantify the frequency of disease by developing a definition of the disease, instituting a mechanism for counting cases of disease within a population, and determining the size of that population.

Method to control interviewer bias

training of study personnel

a. Only the population at risk contributes to the denominator of the cumulative incidence

true

d. All other things being equal, when a new prevention measure for a disease is developed, the prevalence of the disese will decrease over time.

true

e. all other things being equal, when a treatment is developed that prolongs the life of people suffering from a disease, the prevalence of the disease will increase over time.

true

What distincitve features of experimental studies enhance their ability to produce scientifically rigorous results?

unique features include random assignment of subjects to the treatment and comparison groups to contorl for confoudning and to reduce biased allocation, and the use of placebo controls to permit masked assessment of the outcomes.

William Farr

was the compiler of statistical abstracts in great Britain from 1839 through 1880. he pioneered many activities encompassed by modern epidemiology, including the calculation of mortality rates using census data as the denominator.

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