Epidemiology/ Study types

Question 1

What is epidemiology?

Answer 1

The study of the distribution and determinants of
health-related states or events in specified
populations, and the application of this study to the
control of health problems.

Question 2

Descriptive vs analytical epidemiology

Answer 2

Descriptive:
* Describes occurrence of disease
* Determinants within a population

Analytical:
* Explores the quality and amount of influence that determinants have on the occurrence of disease.
* Explores “how” health events occur
* Usually through studies with group comparisons

Question 3

What is a cross sectional study (prevalence study)

Answer 3

Observational study that looks at the relationship between health related characteristics and other variables of interest withiin a defined population at one particular time.

Question 4

What is a case control study

Answer 4

Observational study that looks at persons with a disease or condition and a suitable control group of persons without the condition, and comparing how frequently a suspected attribute or risk factor is present in each group.

Question 5

What is a cohort study (incidence study)

Answer 5

Observational study that follows 2 groups of people those with and those without an exposure over time, comparing how frequently an outcome occurs in each group.

Question 6

4 examples of factors that can impact health outcomes

Answer 6

Innate factors, acute factors, chronic factors, time-varying factors

Question 7

Prevalence is..

Answer 7

The proportion of the population that has disease at a
particular time

Question 8

Incidence risk is..

Answer 8

is the total number of new cases divided by the population at risk
at the beginning of the observation period

Question 9

Sources of bias

Answer 9

Selection bias, attribution bias, observer bias, procedure bias, response bias, misclassification bias.

Question 10

Advantages of cross sectional studies

Answer 10

• rapid generation of data
• multiple variables at time of snapshot
• easy to conduct, cheap

Question 11

Disadvantages of cross sectional studies

Answer 11

• cant analyse over time
• Cant determine cause and effect
• timing is not representative
• inefficient for rare diseases
• prone to bias

Question 12

Relative risk formula

Answer 12

RRR = IRunexposed – IRexposed / IR unexposed
(IR-incidence rate or relative risk)

Question 13

Absolute risk formula

Answer 13

ARR = IRunexposed – IRexposed
(IR-incidence rate or relative risk)