Principles of Epidemiology

Calculations and Interpretations: Answer the following questions in the space provided. Show all of your work.

- Evidence of an increased risk of lung cancer associated with cigarette smoking was sought by Doll and Hill. In one study, 649 lung cancer cases were matched by age, and gender to 649 controls; 647 of the cases and 622 of the control had a history of smoking cigarettes.

- Name the type of study.

- Create the appropriate 2X2 table for the study. (2 points)

Lung Cancer Controls

Smokers 647 622

Nonsmokers 2 27

Total 649 649

- Calculate the appropriate measure of association for the study. (4 points)

- Interpret the results. (2 points)

- In another study, the smoking habits of 34,445 male physicians were obtained by mailed questionnaires. Deaths among these physicians over the subsequent years were identified though contact with the office of the Registrar General. The death rates from lung cancer of these physicians classified by smoking habits were :

Standardized Death Rates per 1000 Persons Aged 35 or More per Year

Nonsmokers 0.07

Cigarette Smokers 0.96

- Name the type of study. (2 points)

- Calculate the Relative Risk for smokers as compared to nonsmokers. (6 points)

- Interpret the results (2 points)

Annual Death Rates per 100,000 Persons

Exposure Category Lung Cancer Coronary Heart Disease

Heavy Smokers 166 599

Nonsmokers 7 422

- Calculate the relative risk from Lung Cancer Mortality for Heavy Smokers compared to non smokers. ( 4 points)

** **

- Calculate the attributable risk of Lung Cancer from smoking. (4 points)

** **

- Interpret the results. (2 points)

- Calculate the percent attributable risk of Coronary Heart Disease due to smoking (4 points)

- Interpret the results. (2 points)

** **

- Convert the following incidence rates to attributable risk using the additive model: (5 points)

Incidence Rates Relative Risks

Factor A Factor A

_ + _ +

Factor B – 3.0 9.0 ** **

_____________________________________ __________________________________

+ 15.0 21.00

- Calculate the concordance rate for the following data: (5 points)

Twin 1

Has Leukemia Does Not Have Leukemia

Twin 2 Has Leukemia 14 1

Does Not Have Leukemia 26 36