Question 1

Suppose eight workers died because of exposure to a toxic chemical. What is the average YPLL for these workers, given their ages at death were 22, 25, 25, 35, 40, 48, 49, and 62 years. Use age 65 years as the endpoint.

Accepted Answer

The answer of Suppose eight workers died because of exposure...

Question 2

In a case-control study, misclassification due to recall bias may be termed:

Accepted Answer

Recall bias in a case-control study leads to differential misclassification because the accuracy of the information recalled differs between cases and controls.

Question 3

Which of the following is a type of selection bias in case-control studies?

Accepted Answer

Berkson's bias and Neyman's bias are both types of selection bias that can occur in case-control studies. Berkson's bias arises when the study population is selected from a hospital setting, leading to an overrepresentation of certain conditions. Neyman's bias, also known as prevalence-incidence bias, occurs when cases are selected at a point in time, potentially missing those who have died or recovered.

Question 4

How can confounding be controlled at the design level of a case-control study?

Accepted Answer

Restriction is a method used at the design level to control confounding by limiting the study to individuals who fall within a certain category of the confounding variable.

Question 5

Which study design is appropriate for determining the incidence of disease?

Accepted Answer

A cohort study is appropriate for determining the incidence of disease as it follows a group of individuals over time to see who develops the disease.

Question 6

There are several potential measures that can be used when assessing the association between variables. Which measure is most appropriate for a case-control study?

Accepted Answer

In a case-control study, the odds ratio is the most appropriate measure because it compares the odds of exposure in cases versus controls.

Question 7

Which of the following is an advantage to using a run-in period in an intervention study?

Accepted Answer

A run-in period helps to identify and exclude participants who are non-compliant or likely to drop out, thus minimizing bias due to loss to follow-up.

Question 8

What is the primary limitation with using a nonrandomized clinical trial?

Accepted Answer

Nonrandomized clinical trials cannot effectively control for unmeasured confounding variables, which can lead to biased results.

Question 9

Which study design focuses on testing preventive measures?

Accepted Answer

A prophylactic trial is specifically designed to test preventive measures, such as vaccines or lifestyle changes, to prevent disease.

Question 10

What would you call an experimental study where the levels of exposure to a presumed cause differ among a population in a way that is relatively unaffected by extraneous factors so that the situation resembles a planned experiment?

Accepted Answer

A natural experiment is a study where the conditions are naturally occurring, allowing researchers to observe the effects of a variable in a setting that resembles a controlled experiment, with minimal influence from external factors.

Question 11

Three principles guide research that involves human participants. These are:

Accepted Answer

The three principles guiding research involving human participants are respect for persons, beneficence, and justice, as outlined in the Belmont Report.

Question 12

Which of the following best describes a phase II trial?

Accepted Answer

Phase II trials are relatively small, randomized, blinded trials that test the tolerability and different doses of an intervention on surrogate or clinical outcomes.

Question 13

For questions , refer to the following table that reflects population statistics for a hypothetical community.
 
-What is the maternal mortality rate?

Accepted Answer

The answer of For questions , refer to the following...

Question 14

For questions , refer to the following table that reflects population statistics for a hypothetical community.
 
-What is the infant mortality rate?

Accepted Answer

The infant mortality rate is typically much lower than the numbers provided in options A, B, and C. The global average is around 29 per 1,000 live births, making option D the closest, but still not accurate.

Question 15

For questions , refer to the following table that reflects population statistics for a hypothetical community.
 
-What is the abortion rate?

Accepted Answer

The answer of For questions , refer to the following...

Question 16

For questions , refer to the following table that reflects population statistics for a hypothetical community.
 
-What is the cause-specific mortality rate for those who died from heart disease?

Accepted Answer

The answer of For questions , refer to the following...

Question 17

Refer to the following data
 
-Which of the following is the age-adjusted rate for population B, using population A as the standard?

Accepted Answer

The answer of Refer to the following data
 
-Which of...

Question 18

Refer to the following data
 
-Which of the following reflects the crude mortality rate ratio for A to B?

Accepted Answer

The answer of Refer to the following data
 
-Which of...

Question 19

In a cohort breast cancer study, a woman is considered to be "exposed" if she first gave birth at age 30 or older. In a sample of 4540 women who gave birth to their first child before the age of 30, 65 developed breast cancer. Of the 1628 women who first gave birth at age 30 or older, 31 were diagnosed with breast cancer.
-What is the excess risk of breast cancer in those who had their first child at age 30 or older?

Accepted Answer

The excess risk is calculated by finding the difference in incidence rates between the two groups. The incidence rate for women who gave birth before age 30 is (65/4540) and for those who gave birth at age 30 or older is (31/1628). The difference is approximately 4.7 per 1,000.

Question 20

In a cohort breast cancer study, a woman is considered to be "exposed" if she first gave birth at age 30 or older. In a sample of 4540 women who gave birth to their first child before the age of 30, 65 developed breast cancer. Of the 1628 women who first gave birth at age 30 or older, 31 were diagnosed with breast cancer.
-Estimate the percentage of the disease among the exposed that is attributed to the exposure.

Accepted Answer

The percentage of the disease among the exposed that is attributed to the exposure is calculated as (RR-1)*100, where RR is the relative risk. The relative risk is calculated as the incidence rate among the exposed divided by the incidence rate among the unexposed. The incidence rate among the exposed is 31/1628 = 0.0190 and the incidence rate among the unexposed is 65/4540 = 0.0143. Therefore, the relative risk is 0.0190/0.0143 = 1.33. The percentage of the disease among the exposed that is attributed to the exposure is (1.33-1)*100 = 25%.

Quiz 13: Epidemiology and Disease Control

Suppose eight workers died because of exposure to a toxic chemical. What is the average YPLL for these workers, given their ages at death were 22, 25, 25, 35, 40, 48, 49, and 62 years. Use age 65 years as the endpoint.

In a case-control study, misclassification due to recall bias may be termed:

Which of the following is a type of selection bias in case-control studies?

How can confounding be controlled at the design level of a case-control study?

Which study design is appropriate for determining the incidence of disease?

There are several potential measures that can be used when assessing the association between variables. Which measure is most appropriate for a case-control study?

Which of the following is an advantage to using a run-in period in an intervention study?

What is the primary limitation with using a nonrandomized clinical trial?

Which study design focuses on testing preventive measures?

What would you call an experimental study where the levels of exposure to a presumed cause differ among a population in a way that is relatively unaffected by extraneous factors so that the situation resembles a planned experiment?

Three principles guide research that involves human participants. These are:

Which of the following best describes a phase II trial?

For questions , refer to the following table that reflects population statistics for a hypothetical community. -What is the maternal mortality rate?

For questions , refer to the following table that reflects population statistics for a hypothetical community. -What is the infant mortality rate?

For questions , refer to the following table that reflects population statistics for a hypothetical community. -What is the abortion rate?

For questions , refer to the following table that reflects population statistics for a hypothetical community. -What is the cause-specific mortality rate for those who died from heart disease?

Refer to the following data -Which of the following is the age-adjusted rate for population B, using population A as the standard?

Refer to the following data -Which of the following reflects the crude mortality rate ratio for A to B?