Height, urban-born and prostate cancer risk in Japanese men

Background: Height and early-life environments have received attention as risk factors for prostate cancer. However, the evidence is sparse in Japan. To elucidate the associations of height and early-life factors with prostate cancer risk in Japanese men, we conducted a hospital-based case-control study. In addition, to investigate whether the associations vary between prostate cancer and other major cancers, we conducted a comparative study within the same case-control study. Methods: Study subjects consisted of 282 prostate cancer cases, 584, 461, 231, and 156 male stomach, lung, colon and rectal cancer cases, respectively, and 1730 male hospital controls, aged 50 and over admitted to a single hospital in Miyagi Prefecture from 1997 to 2003. Information on height and early-life factors including birthplace and stature at 12 years was collected using a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated for each exposure variable. Results: A significant positive association was found between height and prostate cancer risk (OR, 1.52; 95% CI, 1.00-2.31, between the highest and lowest quartiles; P for trend = 0.03). A significant association of urban-born with prostate cancer risk was also found (OR, 1.48; 95% CI, 1.03-2.13). Analyses by stage revealed that height might be more strongly associated with the risk of advanced prostate cancer. For other major cancers, no significant association with height and early-life factors was observed. Conclusions: Height and early-life factors were significantly associated with prostate cancer risk. Compared with other major cancers, these associations were specific to prostate cancer.