Module 5: Epidemiological Research

Question 1

Epidemiology

Answer 1

The study of the distribution and determinants (causes, risk factors) of health-related states and events in specified populations

Question 2

What are the 2 types of Epidemiology?

Answer 2

1. Descriptive
2. Analytic

Question 3

What is cross-sectional epidemiology research design?

Answer 3

Collects information at a SPECIFIC POINT IN TIME (versus over time)

Can be used to describe a population and its characteristics (including disease prevalence) at a SPECIFIC POINT IN TIME

Question 4

Define Prevalence.

Answer 4

Refers to the proportion of persons who HAVE a condition at or during a specific time period

Question 5

Define Incidence.

Answer 5

Refers to the proportion or rate of persons WHO DEVELOP the condition during a particular time period

Question 6

When analyzing cross-sectional data, what are the 2 options?

Answer 6

1. You can split up the groups initially, OR
2. You can look at them after you collect your data

Question 7

2x2 Contingency Tables

Answer 7

Used to interpret Epidemiological data to determine RISK.

It has a very specific format, the disease or the variable of interest is listed across the top, with the exposure listed on the left side column. You then have the numbers for each combination plugged into the associated cells below. Then you can calculate the prevalence ratio (which is an estimate of the magnitude of the association between the exposure and the disease).

Question 8

Cohort

Answer 8

A large group of individuals who share a common characteristic and are OBSERVED OVER TIME to gather information about exposures, that can affect an outcome

Question 9

What the 3 Types of Research Designs in Epidemiology?

Answer 9

1. Cross-Sectional
2. Cohort (prospective or retrospective)
3. Case-Control

Question 10

(TRUE/FALSE)

Cohort studies have an intervention and are randomly assigned.

Answer 10

FALSE

There is no intervention or randomization in cohort studies

Question 11

(TRUE/FALSE)

Cohort studies gives incidence of a disease.

Answer 11

TRUE

Question 12

What are 2 limitations of a Cohort study?

Answer 12

1. More expensive
2. More time-consuming

Compared to cross-sectional studies because you now have to hire enough people to follow these cohort individuals over a period of time

Question 13

What is this type of study?

Identifying the population, recruiting, and enrolling participants, getting baseline measurements, then following them over time to evaluate exposures and disease incidence.

Answer 13

Prospective Cohort study

Question 14

What is this type of study?

Identifying the population prior to developing the disease or outcome, then collecting health information and exposure incidences collected in the past

Answer 14

Retrospective Cohort Study

Question 15

Define Risk Ratio (Relative Risk).

Answer 15

Another way to interpret data, especially in Epidemiology

RR tells who is likely to develop the disease in an exposed/treated group versus a non-exposed group, BASED ON INCIDENCE DATA

Question 16

**WHAT WOULD AN RR OF 1.0 MEAN?

Answer 16

There is NO difference between groups

Question 17

**WHAT WOULD AN RR > 1.0 MEAN?

Answer 17

RR GREATER THAN 1.0

There is an INCREASED risk in the exposed group.

Question 18

**WHAT WOULD AN RR < 1.0 MEAN?

Answer 18

RR LESS THAN 1.0

There is a DECREASED risk in the exposed group

Question 19

How do you interpret an RR of 3.0? **

Answer 19

It would mean the exposed group would be 3x more likely to have the outcome, OR by 200% more than non-exposed group

(RR-1) x 100

Question 20

How would you interpret an RR of 0.25? **

Answer 20

It would mean that the exposed group would be 75% LESS risk of having the outcome

(0.25-1) x 100

Question 21

(TRUE/FALSE)

When interpreting the RR, the next step is to look at the confidence interval.

Answer 21

TRUE

Question 22

What is the Confidence Interval?

Answer 22

95% of data points would fall within this range

Question 23

What are the 2 considerations when interpreting CI?

Answer 23

1. NARROWER IS BETTER (so CI of 0.2 to 0.4 would be stronger than 0.2 to 0.7)
2. IF IT CONTAINS 1.0, THEN THE RR IS NOT LIKELY TO BE STATISTICALLY SIGNIFICANT AND MAY SIMPLY BE A MATTER OF CHANCE.

(A 1.0 means there is no difference between the exposed and the non-exposed)

Question 24

Explain Case-Control as a Epidemiological research design.

Answer 24

Start with the outcome of interest (disease); make groups of with (CASE), or without (CONTROL) outcome; then use retrospective data on each to identify exposures to determine ODDS RATIOs

Question 25

What is Odds Ratios (OR)?

Answer 25

The odds that a case has experience a risk/exposure versus the odds that a control has experienced that same risk/exposure

Does not show causality, but helps identify possible causal factors

Question 26

OR = 1.0

Answer 26

no difference b/t cases and controls

Question 27

OR > 1.0

Answer 27

Increased frequency of exposure among cases and exposure is POSITIVELY RELATED TO A DISEASE

Question 28

OR < 1.0

Answer 28

Exposure is NEGATIVELY RELATED TO THE DISEASE, meaning exposure is protective against the disease