When doing calculations:

• Keep values unrounded in intermediate calculations, and round only the final result.

Round to TWO digits after the decimal point OR a whole number percentage. For example, a final result of 0.6789 rounds to 0.68 or can be expressed as 68%.

In 2015, a team of epidemiologists interested in the incidence of lung cancer among daily cigarette smokers identified a study population of 4,500 men, aged 65-74 years, in Cedar Rapids, Iowa. At baseline, initial tests indicated that 8% of men already had lung cancer. The remaining men were interviewed about their smoking behavior and followed prospectively for 5 years to determine incidence of lung cancer. At baseline, 30% of participants were identified as daily smokers. By the end of the follow-up, 156 smokers and 80 non-smokers developed lung cancer.

	Smokers	Non-smokers	Total
Cancer
No Cancer
Total

a. Calculatethe Cumulative Incidence (CI) for smokers, nonsmokers and the entire cohort population. Interpreteach of the CI values. (Hint: cumulative incidence = risk; this question should be familiar!)

b. Calculateand interpretthe Risk Ratio (Cumulative Incidence Ratio) due to smoking.

c. Calculate and interprettheOddsRatio (Relative Odds) due to smoking.

(i) Is this a risk OR or an exposure OR? Does the OR overestimate the RR in this study?

d. Calculatethe Attributable Risk (AR) and the AR% due to smoking, and interpret the AR%.

e. There are several assumptions made when calculating the AR. What are these assumptions?

f. Calculate the Population Attributable Risk (PAR) and the PAR%due to smoking, and interpret the PAR%.

(i) There are several assumptions made when calculating the PAR. What are these assumptions?