1. Lesson #11 Relative Risk and the Odds Ratio

2. The risk of disease, given exposure, is: The risk of disease, given no exposure, is: The relative risk is P(D | E) P(D | E’)

3. LC no LC Smoke No Smoke 12 3 88 147 100 150 P(LC | Smoke) =.12 P(LC | No Smoke) =.02 RR = = 6

4. D D’ E E’ Cohort Study n

5. If p = P(event), then odds = The odds of disease, given exposure: The odds of disease, given no exposure:

6. Disease Odds Ratio OR = Can calculate as shown only from a cohort study

7. Case-Control Study n D D’ E E’

8. From a case-control study, we can calculate things like: P(E | D),P(E’ | D),P(E | D’ ), & P(E’ | D’ ) The odds of exposure, given disease:

9. Exposure Odds Ratio OR Can calculate as shown from a case-control study

10. OR D D’ E E’ ab cd a+cb+d OR =

11. The disease odds ratio is also OR OR is used to estimate RR! OR can be calculated in any study design!

12. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR =

13. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR = (150)

14. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR = (150)(180)

15. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR = (150)(180) (120)

16. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR = (150) (50) (180) (120)

17. CHD no CHD High Fat not High Fat 200300 180 120 50 150 OR = (150) (50) (180) (120) = 4.5

18. CHD no CHD HF not HF 200300 180 120 50 150 CHD no CHD HF not HF 200600 360 240 50 150 OR = (150) (50) (180) (120) = 4.5OR = (150) (50) (360) (240) = 4.5 “RR” == 2.56 150/270 50/230 “RR” == 3.15 150/390 50/410

19. Yes No Heavy Light None46 33 10 89 39 82 32 153 Liver Cancer Alcohol Consumption

20. Yes No Heavy Light None46 33 10 89 39 82 32 153 Liver Cancer Alcohol Consumption

21. Yes No Heavy Light None46 33 10 89 39 82 32 153 Liver Cancer Alcohol Consumption