Chapter 5: Principles of Epidemiology

Question 1

Epidemiology

Answer 1

From the Greek word meaning “upon the people”; the study of epidemics; the basic science of public health; “the study of the distribution and determinants of health-related states in specified populations, and the application of this study to control health problems.”

Question 2

Vital Statistics

Answer 2

Figures pertaining to life events, such as births, deaths, and marriages.

Question 3

Case

Answer 3

A particular instance of a disease or outcome of interest.

Question 4

Risk

Answer 4

The probability or likelihood of an event occurring– in this case, the probability that people will acquire a disease.

Question 5

Risk Factors

Answer 5

Clinically important signs associated with an increased likelihood of acquiring a disease.

Question 6

Incidence

Answer 6

The number of new cases of a disease during a specific time period in a defined population.

Question 7

Prevalence

Answer 7

The number of existing cases of a disease or other condition in a given population.

Question 8

Point Prevalence

Answer 8

The amount of a particular disease present in a population at a particular point in time; usually the time a survey was done.

Question 9

Period Prevalence

Answer 9

The amount of a particular disease in a population over a period of time.

Question 10

Prevalence Rate

Answer 10

The proportion (usually the percentage) of persons in a population who have a particular disease or attribute at a particular point in time.

Question 11

Endemic

Answer 11

A disease that occurs regularly in a population as a matter of course.

Question 12

Epidemic

Answer 12

An unexpectedly large number of cases of an illness, specific health-related behavior, or other health-related event in a particular population.

Question 13

Pandemic

Answer 13

An outbreak of disease over a wide geographical area such as a continent.

Question 14

Cohort

Answer 14

A well-defined group of people who are studied over a period of time to determine their incidence of disease, injury, or death.

Question 15

Validity

Answer 15

Measures what it says it was going to measure; accurate.

Question 16

Reliability

Answer 16

Consistent in it’s measurements.

Question 17

Ecological Study

Answer 17

Focuses on groups of people (rather than individuals) and examines the relationship between exposure and disease with the population-level rather than individual-level data. Can be used as the first step in exploring the relationship between an exposure and a disease. Cannot be used to show cause and effect, but generates a theory. Can compare two populations.

Question 18

Cross-Sectional Study

Answer 18

A study where exposure factors (e.g., individual or environmental risk factor, nutrition education) and outcomes (e.g., disease occurrence, eating behavior) are observed or measured at one point in time in a sample from the population of interest, usually by survey or interview. In this design, a researcher examines the association among factors and outcomes using a statistical test for association, but cannot infer cause and effect. A snapshot.

Question 19

Cohort Study

Answer 19

A type of observational analytic study that can be retrospective or prospective in nature. Enrollment in the study is based on exposure characteristics or on membership in a group. Disease, death, and/or other health-related outcomes are then determined and compared. Comparison groups can be defined at the beginning or created later using data from the study.

Question 20

Prospective Cohort Study

Answer 20

Studies enroll individuals and then collect data at many intervals. Look into the future.

Question 21

Retrospective Cohort Study

Answer 21

Studies use an existing longitudinal data set to look back for a temporal relationship between exposure factors and outcome development. Look into the past.

Question 22

Case-Control Study

Answer 22

A type of observational study; involves identifying patients who have the outcome of interest (cases) and matching them with individuals who have similar characteristics, but do not have the outcome of interest (controls). Characteristics, such as previous exposure to a factor (i.e., the hypothesized casual or contributing factors), are then compared between cases and controls.

Question 23

Experimental (Controlled) Trial

Answer 23

Examines preventions and treatments for diseases; investigator actively manipulates which groups receive the agent under study. Can be blind, double blind, controlled and randomized. Most rigorous.