Body mass index, height, and prostate cancer mortality in two large cohorts of adult men in the United States

Body weight and height have both been associated consistently with postmeno pausal breast cancer but less consistently with prostate cancer. The presen t study examined the relationship between body mass index (BMI), height, an d death from prostate cancer in two large American Cancer Society cohorts. Men in the study were selected from the male participants in Cancer Prevent ion Study I (CPS-I; enrolled in 1959 and followed through 1972) and Cancer Prevention Study II (CPS-II; enrolled in 1982 and followed through 1996), A fter exclusions, 1,590 prostate cancer deaths remained among 381,638 men in CPS-I and 3,622 deaths among 434,630 men in CPS-II, Cox proportional hazar ds modeling was used to compute rate ratios (RR) and to adjust for confound ers. Prostate cancer mortality rates were significantly higher among obese (BMI, greater than or equal to 30) than nonobese (BMI, <25) men in both coh orts [adjusted RR, 1.27; 95% confidence interval (CI), 1.04-1.56 in CPS-I; RR, 1.21; 95% CI, 1.07-1.37 in CPS-II], Prostate cancer mortality rates in the CPS-I cohort were lowest for the shortest men (RR, 0.80; 95% CI, 0.63-1 .03 for men <65 inches versus 65-66 inches) and highest for the tallest men (RR, 1.39; 95% CI, 1.11-1.74 for men greater than or equal to 73 inches ta ll versus 65-66 inches). Rates remained constant among men 65-72 inches tal l. No association between height and prostate cancer mortality was observed in the CPS-II cohort (RR, 1.03; 95% CI, 0.82-1.29 for men greater than or equal to 75 versus 65-66 inches). These results support the hypothesis that obesity increases risk of prostate cancer mortality. Decreased survival am ong obese men may be a likely explanation for this association.