EPIB301 MIDTERM

What is the definition of epidemiology?

The study of the distribution and determinants of health-related states or events in specified populations

What are the two main components of epidemiology?

Distribution and determinants.

What are the three core public health functions?

Assessment

What are the key uses of epidemiology?

Understanding disease etiology

Define incidence.

The number of new cases of a disease that occur in a population at risk during a specified time period.

Define prevalence.

The total number of existing cases (new and old) of a disease in a population at a given time.

What is the difference between incidence and prevalence?

Incidence refers to new cases; prevalence includes all cases.

What is mortality rate?

A measure of the frequency of occurrence of death in a defined population during a specified time period.

What are the three categories of descriptive epidemiology?

Person

What is a case definition?

A standard set of criteria for determining whether an individual should be classified as having a disease or health condition.

What are common sources of epidemiologic data?

Vital statistics

What is the difference between primary and secondary data?

Primary data is collected directly by the researcher; secondary data is collected by others for different purposes.

What are person variables in epidemiology?

Age

What is an ecologic study?

A study in which the units of analysis are populations or groups rather than individuals.

What is ecologic fallacy?

The incorrect inference about individual-level relationships based on group-level data.

What is a cross-sectional study?

A study that examines the relationship between diseases and other variables of interest as they exist in a defined population at one point in time.

What are advantages of cross-sectional studies?

Relatively quick and inexpensive

What are disadvantages of cross-sectional studies?

Cannot establish temporality

What is a case-control study?

A study that compares individuals with a disease (cases) to those without (controls) to find past exposures.

What is an odds ratio (OR)?

A measure of association used in case-control studies to estimate the odds of exposure among cases compared to controls.

What is a cohort study?

An observational study where participants are grouped by exposure status and followed over time for outcome occurrence.

Difference between prospective and retrospective cohort?

Prospective follows forward from exposure to outcome; retrospective uses existing records and looks back in time.

What is a randomized controlled trial (RCT)?

An experimental study where participants are randomly assigned to intervention or control groups.

What is the 'intent-to-treat' principle?

Participants are analyzed in the group to which they were randomized

What is a quasi-experimental study?

A study that evaluates interventions but lacks random assignment.

What is confounding?

A distortion in the estimate of the effect of an exposure due to association with another variable related to the outcome.

Criteria for a confounder?

Must be associated with both the exposure and the outcome

What are methods to control for confounding?

Randomization

What is selection bias?

Bias from procedures used to select study participants that leads to a non-representative sample.

What is recall bias?

A type of information bias when participants do not remember past events accurately.

What is the healthy worker effect?

Bias where employed individuals tend to have better health outcomes than the general population.

What is temporality and why is it important?

It refers to the exposure occurring before the outcome; essential for causal inference.

What measure is used in cohort studies to measure association?

Relative risk (risk ratio).

What measure is used in cross-sectional studies?

Prevalence ratio or odds ratio.

What measure is used in RCTs?

Risk ratio or rate ratio.

What was the main objective of Alcalá & Dellor (2019)?

To examine the association between child adversity and use of preventive care among children.

What was the study design in Alcalá & Dellor (2019)?

Cross-sectional.

How was preventive health care (PHC) measured?

Receiving a physical exam or well-child checkup in the past 12 months.

How was adversity measured?

Via a 9-item AFE scale reported by caregivers.

Key finding among uninsured children in Alcalá & Dellor (2019)?

Each additional AFE was associated with 18% higher odds of receiving preventive care.

What was the Tuskegee Syphilis Study?

An unethical study that observed untreated syphilis in Black men without informed consent.

What ethical principles guide human research?

Respect for persons

What is informed consent?

The process of providing participants with clear information about the study and obtaining voluntary agreement.

What is cumulative incidence?

Number of new cases / number of people at risk during a time period.

What is incidence density (rate)?

Number of new cases / person-time at risk.

How do you calculate prevalence?

Number of existing cases / total population at a point in time.

What is risk difference?

Difference in risk between exposed and unexposed groups.

What is attributable risk?

The portion of disease incidence that can be attributed to a specific exposure.

What is internal validity?

The degree to which the results of a study are true for the population being studied.

What is external validity?

The degree to which the study findings can be generalized to other settings or populations.

What is information bias?

Systematic error due to inaccurate measurement or misclassification.

What is non-differential misclassification?

Misclassification that affects both groups equally

What is differential misclassification?

Misclassification that differs between groups