Epi Final Study Guide

Question 1

Define epidemiology

Answer 1

The distribution and determinants of health and disease, morbidity injuries, disabilities, and mortaliy in populations. Studies are applied to the control of health problems in populations

Question 1

Measure of disease frequency, prevalence and incidence, mortality, and morbidity-

Answer 1

Disease frequency:
Prevalence:
Incidence:
Mortality:
Morbidity:

Question 2

Summarize the historical evolution of epidemiology

Answer 2

Where is the disease occurring? (person, place, time = descriptive epi).
Why is it occurring in populations? (modifiable and nonmodifiable risk factors = analytic epi)
How can we prevent and control disease in the population? (control, policy, interventions)

Question 3

Identify the core epidemiology functions

Answer 3

Assessing community health
Making individual decisions
Completing clinical decisions
Searching for causes

Question 4

Specify the elements of a case definition and state the effect of changing the value of any of the elements

Answer 4

Case definition: a set of standard criteria for classifying whether a person has a particular disease, syndrome, or other health condition.
- Standardization is important to ensure that when a difference is observed, the difference is real and not how it’s defined.

Question 5

List the key features and uses of descriptive epidemiology

Answer 5

Studies that characterize the amount and distribution of health in populations
- person, place, time characteristics
- Who, what, where, when

Question 6

List the key features and uses of analytic epidemiology

Answer 6

Examines etiologic (causal) hypotheses regarding the association between exposures and health outcomes in populations.
- Tests hypotheses
- Answers Why and How

Question 7

Measures of association between exposure and outcome (disease) in different study designs

Answer 7

Odds ratio: Measure of association between frequency of exposure/ frequency of outcome in case controls. AD/BC = OR
Rate ratio: difference measure to compare IR of events at any given time
Risk ratio: Measure of IR of exposed/ IR in non-exposed

Question 8

Modern criteria of causality

Answer 8

Plausibility (reasonable pathway to link outcome to exposure)
Consistency (same results if repeat in different time, place, person)
Temporality (exposure precedes outcome)

Question 9

Apply and interpret four measures of spread: range, interquartile range, standard deviation, and confidence interval (for mean)

Answer 9

Range:
IQR:
Standard Deviation:
CI (mean):

Question 10

Describe the basic principles of ethical research as proposed by the Belmont Report

Answer 10

Respect for Persons, Beneficence, and Justice

Question 11

Describe potential data sources and limitations of disease surveillance

Answer 11

Sources of surveillance:
Health surveys
Registries
Clinical and PH research
Information systems
Environmental monitoring
Other data sources

Purpose of PH surveillance:
timeliness
representation
sensitivity
specificity

Question 12

Describe the role of an epidemiologist

Answer 12

Population medicine
Analytic and descriptive epi
Develops hypotheses
Determines who, what, when, where, why, and how of disease
Determines etiology - causes of disease
Identifies patterns and trends
Evaluates effectiveness of interventions
Determines control measures
Informs policy

Question 13

Sensitivity

Answer 13

Proportion of persons testing positive among the affected
- intrinsic
- true positives/ affected persons

Question 14

Specificity

Answer 14

Proportion of persons testing negative among non-affected individuals
- intrinsic
- true negatives/ non-affected

Question 15

Predictive value of a positive test

Answer 15

The proportion of actually affected out of those testing positive.
- Extrinsic
- True positives/persons testing positive
- PVP= A/(A+B)

Question 16

Predictive value of a negative test

Answer 16

The proportion of the non-affected out of those testing negative.
- extrinsic
- true negatives/persons testing negative
- PVN - D/(C+D)

Question 17

Rothman’s Causal Pie

Answer 17

Envisions disease as a pie; each piece = causes of disease
Each piece must come together for the disease to occur in a population.
- Sufficient cause: full pie
- Component cause: pie piece
- Necessary cause: component that is part of everyone’s sufficient

Question 18

Epi Triangle purpose and components

Answer 18

Disease causation is multifactorial***
- Agent: infectious pathogen, chm, or physical rxns that can cause disease or injury
- Host: Human that can get the disease. Risk factors, susceptibility, and response to agents influence host characteristics ; varies by outside forces
- Environment: extrinsic factors that affect agent and opportunity for exposure. biology, climate, SES

Question 19

How do Epis measure disease in populations?

Answer 19

Surveillance systems, surveys, and administrative databases