L1-2 Introduction to Epidemiology

Question 1

What is epidemiology?

Answer 1

The study of patterns, causes & effects of health & disease in defined populations.

Question 2

Name the 2 types of error?

Answer 2

• Random error

- Systematic error

Question 3

Define Random Error.

Answer 3

An error in measurement caused by factors which vary from one measurement to another. Has a zero-mean.

Question 4

Define Systematic Error.

What can it be divided into?

Answer 4

An error having a non-zero mean, so that its effect is not reduced when observations are averaged.

• Selection bias
• Information bias

Question 5

Name the 4 epidemiological study designs.

Answer 5

Case-control studies

Cohort studies

Cross-sectional studies

Ecological studies

Question 6

What is genetic epidemiology?

Answer 6

The study of role of genetic factors in determining health & disease in families & populations.

Question 7

Name the genetic epidemiological study design type:

“Is there a genetic component to the disease & what are the relative contributions of genes & environment?”

Answer 7

Familial aggregation studies.

Question 8

Name the genetic epidemiological study design type:

“What is the pattern of inheritance of the disease (dominant or recessive)?”

Answer 8

Segregation studies.

Question 9

Name the genetic epidemiological study design type:

“On which part of which chromosome is the disease gene located?”

Answer 9

Linkage studies.

Question 10

Name the genetic epidemiological study design type:

“Which allele of which gene is associated with the disease?

Answer 10

Association studies.

Question 11

Name the genetic epidemiological study design type:

“Identified monogenic disorders & genes”

Answer 11

Traditional.

Question 12

Name the genetic epidemiological study design type:

“Have led to discovery of many genetic polymorphisms that influence risk of developing many common diseases”

Answer 12

Genome-wide association studies (GWAS).

Question 13

What is molecular epidemiology?

Answer 13

The use in standard epidemiologic studies of techniques of molecular biology.

Question 14

What is life course epidemiology?

Answer 14

Study of antecedent exposures & later health outcomes.

Question 15

Define health inequalities.

Answer 15

Differences in health status or in distribution of health determinants between different population groups.

Question 16

Define incidence/incidence rate.

Answer 16

A measure of the frequency with which a new case of a disease occurs in a population over a period of time.

Question 17

What is the equation for incidence?

What is the answer often expressed as?

Answer 17

= (new cases occurring during a given time period) / (population at risk during the same time period)

__ per 100,000 persons per year.

Question 18

Define prevalence.

Answer 18

A measure of the frequency of all cases of a particular disease present in a defined population at a given time.

Question 19

What is the equation for prevalence?

What is the answer often expressed as?

Answer 19

= (persons with a given disease/condition during a specified time period) / (population during the same time period)

%

Question 20

Define mortality rate.

Answer 20

A measure of the frequency with which a new deaths occurs in a population over a period of time.

Question 21

Define relative risk?

Answer 21

The ratio of the risk of disease among those exposed to a risk factor to the risk among those not exposed.

Question 22

What is the equation for rate ratio?

Answer 22

= (rate for group of interest)/(rate for comparison group)

Question 23

Rate Ratio = 1

=?

Answer 23

Identical risk in the 2 groups.

Question 24

Rate Ratio > 1

=?

Answer 24

Increased risk for numerator group.

Question 25

Define odds ratio.

Answer 25

Estimate of risk from case-control studies.

Question 26

What is the equation for odds ratio?

Answer 26

(a x d) / (b x c)

where a = no. of persons with disease & with exposure of interest

where b = no. of persons without disease, but with exposure of interest

where c = no. of persons with disease, but without exposure of interest

where d = no. of persons without disease & without exposure of interest

Question 27

In an odds ratio, a+c=?

Answer 27

Total no. of persons with disease (‘cases’).

Question 28

In an odds ratio, b+d=?

Answer 28

Total no. of persons without disease (‘controls’).

Question 29

Define a standard population.

Answer 29

A standard population is an artificial population structure that is used in the weighting of mortality or incidence data to produce age-standardised rates.

Question 30

Define age standardisation/adjustment.

Answer 30

A method used to make fairer comparisons between populations with different age distributions.

Question 31

Rate ratio is less than 1.

=?

Answer 31

Increased risk for denominator group.