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