Question: 1. Assuming Cases Appeared Uniformly Across The Observation Period, What Was The Annual Incidence Of Prostate Cancers In This Group? (express Per 100,000) 2. The CDC Reports Prostate Cancer Incidence At 106.5 Per 100,000 Men Per Year. How Does Your Answer To Number 5 Compare?

Prostate cancer in the most common cancer among men in the US. About 1 man in 9 will be diagnosed with prostate cancer during his lifetime. It is more likely to develop in older men and in African-American men. It is rare in men under 40. The average age at diagnosis is about 66. Aside from testosterone (higher level = higher risk), few risk factors were known at the time of this study. Physical activity level is known to influence testosteronę production. This influence is both direct (physical activity decreases testosterone production) and indirectly (obesity (which leads to higher levels of fats and lower levels of other hormones) increases) testosterone. These facts would suggest that activity would be protective, and obesity would be a risk factor. Prior studies of the relationship between activity, obesity, and prostate cancer were inconclusive. s This study used data from the Harvard Alumni Health Study, a longitudinal prospective cohort study. It included only male, Harvard College graduates who first enrolled between 1916 and 1950 and were still living in 1966. The cohort began with 21,582 individuals. They collected data on lifestyle and health in 1962, 1966, 1977, 1988, and 1993. In 1993, the cohort was down to 11,894 (due to death or being lost to follow-up). The cohort for this study analysis consisted of the respondents to the 1988 data collection but excluded those with a prior cancer diagnosis or missing details on activity and obesity (approximately 10,560). They authors were able to follow 8,922 participants through 1993. The authors assessed whether a cohort member ever had prostate cancer through self-report surveys (of the living) and audits of death certificateş (of the dead). The authors calculated current BMI (body mass index) from self-reported height and weight as well as several other measures of obesity. These measures also were available for the beginning of the Harvard Alumni Health Study as all participants underwent a physical exam at entry. The authors assessed physical activity through several self-reported measures (e.g., estimated number of blocks walked each day, flights of stairs climbed, etc.) and used these data to calculate estimated expended energy to produce a single summative measure reflecting all types and intensities of exercise. The authors also examined associations with known or suspected confounders such as smoking, alcohol, diet, and family history. P-value % Men free of prostate cancer (8483) 66.8 (7.9) 0.0001 0.57 32.9 22.2 16.2. 28.7 0.05 Tabe. Baseline characteristics (1988) Characteristic % Men who had developed prostate cancer by 1993 (n=439) Mean age (SD), years 69.2 (6.8) Physical activity, kJ/week (%) <4200 29.8 4200-8399 24.2 8400-12,599 16.4 >12,600 29.6 Body mass index, kg/m2 %) <22.5 19.8 22.5-24.9 39.2 25.0-27.4 30.5 >27.5 10.5 Waist girth, cm (%) <86.4 23.6 86.5-91.4 30.9 91.5-96.5 24.5 >96.5 21.0 Cigarette smoking (%) Never 34.8 Past 58.5 Current, <20/day 1 4.2 Current, >20/day 2.5 21.4 35.8 28.2 14.7 s 0.09 28.5 27.6 22.0 22.0 . 0.05 36.8 55.1 3.1 5.0 0.008 11.3 18.2 13.7 56.9 17.3 18.2 15.7 48.8 0.81 24.1 Alcohol intake (%) Never Monthly Weekly Daily Red meat intake, servings (%) <3/month 1-2/week >3/week Vegetable intake, servings (%) <6/week 1-2/day >3/day History of prostate cancer in father (%) 44.2 24.1 45.6 30.4 31.8 0.35 23.0 60.1 16.9 25.0 60.4 14.7 7.5