Epidemiology 11-Estimating Risk, is there an association

Question 1

What is relative risk in a cohort study ?

Answer 1

Relative risk

•Relative risk

–Cohort studies

–What is the ratio of the risk of disease in exposed individuals to the risk of disease in nonexposed individuals?

Question 2

What is the formula for relative risk ?

Answer 2

Probability of an event occurring in exposed people compared to the probability of the event in nonexposed people (or the ratio of the two probabilities)

–Relative risk= incidence of exposed/ incidence of nonexposed

Question 3

What does a relative risk of 1 vs grater than 1 mean ?

Answer 3

Relative risk =1

–Risk in exposed persons equals the risk in nonexposed persons

–No association

•Relative risk >1

–Risk in exposed persons is greater than the risk in nonexposed persons

–Positive association and may be causal

Question 4

What is a relative risk of less than 1 mean ?

Answer 4

Relative risk <1

–Risk in exposed persons is less than the risk in nonexposed persons

–Negative association (protective effect)

Question 5

CCalculate incidence of exposed group,nonexposed, and relative risk .

Answer 5

Question 6

In odd ratio in cohort study, do we know the incidence ?

Question 7

Can you draw the formula for Odd ratio

Answer 7

Question 8

What is a odd ratio of 1 vs greater than 1 mean ?

Answer 8

•Odds ratio =1

–No association between exposure and disease

•Odds ratio >1

–Positive association between exposure and disease

Question 9

What is a odd ratio of lesser than one mean ?

Answer 9

Odds ratio <1

–Negative association (protective effect) between exposure and disease

Question 10

Answer 10