Into to Epidemiology

Question 1

denominators

Answer 1

data or facts about a population:

Question 2

Person Time

Answer 2

the time period e.g. number of years a person is exposed to risk

Question 3

X years of follow up

Answer 3

is the time period from which people have been followed up

Question 4

incidence

Answer 4

the occurrence, rate, or frequency of a disease

Question 5

incidence rate

Answer 5

Number of new people with outcome over a time period x 100000
/
total person-time for people in the group AT RISK

Question 6

Prevalence

Answer 6

proportion of persons in a population who have a particular disease

Question 7

point

Answer 7

at a specified time

Question 8

period:

Answer 8

over a specified period

Question 9

period prevalence rate

Answer 9

Number of people with outcome during a time period x 100
/
Average number of people in a group

Question 10

Different types of exposures

Answer 10

non-modifiable:
- age, sex, genotype 
modifiable;
- smoking, weight, diet, alcohol consumption
interventions - special kind
- drug therapy 
- surgery
- lifestyle advice

Question 11

risk

Answer 11

number of outcomes in a group
/
number of people in the group

x 100

Question 12

relative risk

Answer 12

risk in exposed / risk in unexposed

Question 13

relative risk reduction

Answer 13

(1-relative risk) x 100

Question 14

absolute risk reduction

Answer 14

risk in unexposed - risk in exposed

Question 15

number needed to treat

Answer 15

1 / absolute risk reduction

Question 16

confidence intervals

Answer 16

– “A confidence interval can be thought of as a range of plausible values”
– Values near the limits less plausible than those in the middle
– The wider the interval the greater the uncertainty

Question 17

cross-sectional study - past

Answer 17

sample a popultion 
estimate the proportion:
- different exposures 
- different signs/symptoms
- different outcomes
use data 
- to describe prevalence/burden
- to explore associations

Question 18

case-control study - past

Answer 18

• Select cases with an outcome
• Select controls without the outcome
• Explore EXPOSURES in cases and controls • Compare exposures in cases and controls
• Identifyassociation

Question 19

cohort study - future and past

Answer 19

• Select people without an outcome
• Classify according to an exposure
• Follow-up
– Prospective = during the time period
– Retrospective past
• Compare RISK of disease in exposed and unexposed

Question 20

randomised controlled trial - future

Answer 20

Random allocation
– Intervention
– Control/comparator
• Compare RISK of outcome in intervention and control groups