Epidemiology

Question 1

What is epidemiology?

Answer 1

The study of health and disease in populations

Question 2

What is sensitivity?

Answer 2

If disease positive, the chance of being test positive

Question 3

What is specificity?

Answer 3

If disease negative, the change of the test being negative

Question 4

What is the predictive value of a positive test?

Answer 4

If tested positive, the chances of being disease positive

Question 5

What is the predictive value of a negative test?

Answer 5

If tested negative for a disease, the chances of being negative

Question 6

What is true prevalence?

Answer 6

Number of Disease positive

Question 7

What is apparent prevalence?

Answer 7

Number of test positive

Question 8

What is a cause? Usually multiple

Answer 8

Environmental or individual characteristics which affects the incidence of disease

Question 9

What is a risk factor?

Answer 9

A variable whose presence or absence influences the incidence of a disease
Can be direct/indirect

Question 10

What are associations?

Answer 10

Examining whether a variable is a risk factor, by examining the association between the variable and disease

Question 11

What is the population at risk?

Answer 11

The number of individuals at risk from contracting a disease

Can be entire population

Question 12

What is prevalence?

Answer 12

The number of individuals with a disease at a given time

Question 13

What is incidence?

Answer 13

The number of new cases within a time period, as a proportion of those at risk

Question 14

What is the equation for incidence rate?

Answer 14

Number of new cases/ population at risk

Question 15

What is incidence risk?

Answer 15

The probability of an event occuring in a number of individuals followed for a period of time

Question 16

What is relative risk/rate?

Answer 16

How many more times likely you are to contract a disease due to a risk factor

Question 17

WHat is attributable risk/risk difference?

Answer 17

The risk of a disease in exposed individuals that can be associated with the risk factor

Question 18

What is attributable rate difference?

Answer 18

The disease rate in exposed individuals that can be attributed to the risk factor

Question 19

What is an endemic?

Answer 19

The constant presence of a disease (always there)

Question 20

What is an epidemic?

Answer 20

A sharp increase of a disease above normal levels

Question 21

What is an outbreak?

Answer 21

A sudden epidemic of short duration

Question 22

What is a pandemic?

Answer 22

A worldwide epidemic

Question 23

What is a confounding variable?

Answer 23

An outside influence that changes that outcome of an experiment

Question 24

How do you deal with confounding variables?

Answer 24

Stratification
Matching
Attempting corrections

Question 25

What is bias?

Answer 25

Something that makes non-random differences between groups being studied

Question 26

What is population? What happens as this increases?

Answer 26

Total number of individuals | Becomes normal distribution

Question 27

What is a sample? What is the problem with sampling?

Answer 27

A random selection of the population | Leads to uncertainty

Question 28

What is a variable?

Answer 28

A characteristic that can be different in individuals | Can be categorical, quantities or ordinal (very ill, moderately ill, not ill)

Question 29

What is used to calculate statistical signifcance?

Answer 29

Null hypothesis Alternative hypothesis Confidence limits P value

Question 30

What happens to specificity as sensitivity increases?

Answer 30

Decreases

Question 31

What happens to the predictive value of a positive test as prevalence increases?

Answer 31

Also increases

Question 32

When there is a low true prevalence, what happens to apparent prevalence?

Answer 32

Over estimation

Question 33

What are the 3 types of epidemiological study?

Answer 33

Descriptive Analytical Experimental

Question 34

What are the 4 types of analytic study?

Answer 34

``` CLCG Cross sectional Longitudinal Group based Case control ```

Question 35

What is a cross sectional study? When is it not suitable?

Answer 35

Studying the prevalence of a condition and the possible risk factors For low incidence/short duration

Question 36

What is a longitudinal/cohort study and what are the advantages and disadvantages?

Answer 36

Follows a group for a period of time to see which individuals develop a disease Expensive and time consuming All individuals start healthy - informative

Question 37

What is a case control study?

Answer 37

Looks at individuals with disease and compares with those without a disease (similar age, gender etc)

Question 38

What is a group based study?

Answer 38

Comparing the experience of a population without examining characteristics

Question 39

In general, what are analytical studies?

Answer 39

Examining the situation between characteristics, causes and outcomes of a disease

Question 40

What is a descriptive epidemiological study?

Answer 40

Study which describes the situation of a disease in a population

Question 41

What are experimental studies?

Answer 41

2 types intervention studies put animals at subject to risk factor clinical trials look for treatment