PH 425
The primary assumption underlying screening activity is that early detection and intervention will ultimately result in fewer deaths due to that disease.
True
When conducting ecologic studies of migrant health, one must remember that the health of immigrants might be affected not only by their new environment, but also the stress inherent in making such a drastic life change.
True
Years of potential life lost is generally greater for injuries than for cancer.
True
Which of the following studies could, ethically, be answered using a randomized controlled trial in humans?
Which is better for treating mild hypertension: hydrochlorothiazide (a diuretic) or atenolol (a beta-blocker)?
Why can't one make causal inferences based on results of a cross-sectional study?
because exposure and outcome data are collected at the same time
Edward Jenner
Exposure to cow pox caused immunity to small pox
A cross-sectional study is good for establishing duration of disease.
False
A study population and a study sample are essentially the same thing.
False
An event, condition, or characteristic that is neither necessary nor sufficient cannot be considered a causal factor for a disease.
False
As long as all measurement methods are identical for all study participants, you don't need to worry too much about whether or not those measurements are accurate.
False
As of May 14, 2014, there had been 4 confirmed cases of MERS in the United States.
False
Cross-sectional studies can yield data on incidence but not prevalence.
False
Definitions of who "has" a disease must be less strict for research purposes, when compared to clinical.
False
Ecologic studies are the final phase in determining causation; their results are considered indisputable.
False
For a case-control study, you choose study participants based on their exposure status.
False
If an event, condition, or characteristic is not a sufficient cause, then removing it will not prevent any cases of disease.
False
In a case-control study, you select cases based on who's been exposed.
False
In a cohort study, it is important that participants be free of ALL diseases at the start of the follow-up period.
False
Incubation periods for infectious diseases are always less than 10 days.
False
It is easier to study whole populations than samples of the population.
False
Prevalence is a measure of risk.
False
Prevalence is best suited to capturing acute (e.g., short duration) illnesses.
False
Quality of life is subjective, and therefore has no value as an outcome in epidemiology studies.
False
Reporting is generally more accurate when passive, rather than active, surveillance methods are used.
False
Results from epidemiology studies are intended to be used to guide decision making for individuals.
False
Screening tests are best used after the "critical point" for the disease has passed.
False
The "population at risk" consists of people who would be counted as cases if they develop the disease being studied.
False
The number of people dying from cancer is increasing, therefore the risk of dying from cancer is also increasing.
False
Thus far, all confirmed MERS cases in the US are within one family.
False
Residents of three villages with three different sources of water supply were asked to participate in a survey to identify cholera carriers. Because several cholera deaths had occurred lately, nearly everyone agreed to be examined. The proportion of residents in each village who were carriers was computed and compared. What kind of study was this?
cross-sectional
The best synonym for "spurious" is:
deceptive
An investigator calculates a crude rate ratio of 8.5. She then stratifies by age (>50, <= 50) and finds stratum-specific rate ratios of 2.5 for older participants, and 2.3 for younger participants. She calculates an adjusted rate ratio of 2.4. When reporting results, she should:
report the adjusted rate ratio
An investigator calculates a crude rate ratio of 8.5. She then stratifies by age (>50, <= 50) and finds stratum-specific rate ratios of 12.2 for older participants, and 2.5 for younger participants. She calculates an adjusted rate ratio of 8.3. When reporting results, she should:
report the stratum-specific rate ratios
The theoretical range for an odds ratio is 0 - infinity.
true
To be a potential confounder, the co-variable in question must be associated with the exposure, and causally related to the outcome.
Associated Causally related
The primary purpose of double blinding in a randomized controlled trial is to:
Avoid observer and subject bias
An event, condition, or characteristic that can produce disease on its own is called a
Component cause
Ignaz Semmelweis
Handwashing
___________ refers to the resistance of a group of people to an attack by a disease to which a large proportion of the group's members are immune.
Herd Immunity
Which of the following describes a randomized, controlled trial?
In a study on physical activity and serum lipid levels, one group of participants is asked to go to the gym 4 days per week, and the other group is asked to be completely sedentary. Participants are followed for 6 weeks, and serum lipid levels compared.
John Snow
Investigated cholera outbreak
The major purpose of random assignment in a clinical trial is to:
Reduce selection bias in the allocation of treatment
An investigator calculates a crude rate ratio of 8.5. She then stratifies by age (>50, <= 50) and finds stratum-specific rate ratios of 8.6 for older participants, and 8.1 for younger participants. She calculates an adjusted rate ratio of 8.3. When reporting results, she should:
Report the crude rate ratio
_______ and _________are characteristics of the test and do not change as prevalence of disease changes, whereas ________ and __________will vary as disease prevalence varies.
Sensitivity and specificity PPV and NPV
Which of the following describes an ecological study?
The "average" diets for two countries are compared with respect to the average life expectancies for those two countries.
If the risk ratio for the association between an exposure and an outcome is substantially less than 1.0, then:
The exposure is associated with reduced risk of the outcome
The CDC, in their prevention efforts, is assuming an incubation period of 14 days.
True
As epidemiologists, we are often interested in whether or not the exposure allows people to live better, not just live longer.
True
Cohort studies are good for studying rare exposures.
True
Ecologic studies are of value because they can be relatively inexpensive, and may point researchers in the direction of a relationship worthy of further examination.
True
Epidemiology studies usually use fairly strict definitions of "diseased."
True
Etiologic relationships cannot be determined using cross-sectional studies.
True
If a study reports a risk ratio of 1.0, then in that study there was no statistical association between the exposure and the disease.
True
Incidence is a measure of risk.
True
Selection bias occurs when subjects in the study sample are not representative of the target population about which conclusions are to be drawn.
True
Selection bias occurs when subjects studied are not representative of the target population about which conclusions are to be drawn.
True
The CDC has attempted to contact everyone who travelled on the same flights as the MERS-infected individuals whose final destination was in the US.
True
An investigator calculates a crude rate ratio of 8.5. She then stratifies by age (>50, <= 50) and finds stratum-specific rate ratios of 2.5 for older participants, and 2.3 for younger participants. She calculates an adjusted rate ratio of 2.4. In this case, age is acting as a(n):
confounder
An investigator calculates a crude rate ratio of 8.5. She then stratifies by age (>50, <= 50) and finds stratum-specific rate ratios of 8.6 for older participants, and 8.1 for younger participants. She calculates an adjusted rate ratio of 8.3. In this case, age is acting as a(n):
nothing
Incidence
number of new cases / sum of person time at risk
Case Fatality Rate
percent of people who have a disease who die withing a certain time after diagnosis
The 3 leading causes of death in the US in 1900 were:
pneumonia/influenza, tuberculosis, diarrhea
The unit of observation in an ecological study is:
the community
Mortality Rate
total number of deaths from a disease / total number of people at risk during a period of time
Indicate the two denominators one could use to calculate incidence
total number of people at risk accumulated person-time at risk
Biological markers of exposure are only useful if they are not altered by the disease process.
true
In epidemiology, the strength of a factor's association with a given disease can be measured by the change in disease frequency that occurs following introduction or removal of the factor from a population.
true