Epidemiology 4

Question 1

What is a risk factor

Answer 1

environmental, behavioral or biological factor confirmed by temporal sequence, usually increasing the probability of a disease occurring and if absent or removed reduces the probability

Question 2

What is th concept of a cause

Answer 2

most disease result from exposure of susceptible invidious to more than one causal agent
exposure to causal agent does not inevitably result in disease

Question 3

What do we look at when investigating cause complex

Answer 3

characteristics of susceptible/resistant individual

types of exposure to external agent

Question 4

What is the Bradford hill criteria for a causal association

Answer 4

strength of association 
dose response
change in risk factor - reduction
time sequence
consistency 
specificity - defined exposures 
biological plausibility
experimental preventive trials

Question 5

What is a cause

Answer 5

external agent which results in disease in susceptible individuals
not all factors are associated with occurrence of disease are causes
some factors may be associated independently with a causal agent but do not themselves cause disease or increase risk of developing disease

Question 6

What is a confounding variable

Answer 6

Particular type of variable which for some reason has been left uncontrolled

Question 7

What is descriptive epidemiology

Answer 7

can only go so far
patterns and trends, not causes
hypothesis generating
ecological fallacy

Question 8

What is a risk factor hypothesis

Answer 8

suggestion that exposure to a particular agent may cause the development of a particular disease if susceptible individual exposed to agent in question

OR suggest that possession of certain characteristics make disease outcome more likely if exposed to certain agents

Question 9

What are the 3 common indices of risk

Answer 9

absolute
relative
attributable

Question 10

What is absolute risk

Answer 10

most basic measure
incidence rate of disease amongst people exposed to agent
not very useful, as assumes no risk incurred by people not exposed to agent

Question 11

What is attributable risk

Answer 11

difference between incidence rates in exposed and non exposed groups

represents the risk attributable to factor being investigated

Question 12

What is relative risk

Answer 12

ratio of incidence rate in exposed group to incidence rate in non exposed group

measurement of proportionate increase in disease rates of exposed group

makes allowance for frequency of disease amongst people not exposed to supposed harmful agent

Question 13

What are analytic observational studies searching for

Answer 13

association between factor or set of factors and a disease

investigate observes what is happening normally in population

involves comparing disease experience of two or more groups of people in relation to their possession fo certain characteristics or exposure to a suspected factor of factors

Question 14

What are analyti observational studies designed for

Answer 14

test specific hypotheses
aim to define risk factors of disease more precisely
form results may be possible to suggest ways of preventing/controlling disease

Question 15

What are the two main types of study

Answer 15

cohort

case control

Question 16

What is a descriptive observational study

Answer 16

cross sectional

Question 17

What are cohort studies

Answer 17

prospective studies
recruit groups of people who have not manifested the disease at time of recruitment and assess risk factors
individuals over period of time measure frequency of occurrence of disease among people exposed to risk factor and people not exposed to risk factor

Question 18

What are case control studies

Answer 18

retrospective studies
compare individuals with cases with those without disease (control)
trace back risk factors

Question 19

Which is more robust, cohort or case control

Answer 19

cohort