Body size and prostate cancer: A population-based case-control study in China

We conducted a population-based case-control study in China to investigate whether body size plays a role in prostate cancer etiology and whether it c an explain the rapid increase in prostate cancer incidence rates in China. A total of 238 cases newly diagnosed with primary prostate cancer in Shangh ai, China, during 1993-1995 were included in the study. Four hundred and se venty-one healthy control subjects were randomly selected from among reside nts of Shanghai and frequency-matched to cases on the basis of age. In-pers on interviews were conducted to elicit information on height, weight histor y, and other lifestyle factors, Waist and hip circumferences were measured at interview. Odds ratios (ORs) were used to measure the association betwee n prostate cancer and anthropometric variables including height, weight, bo dy mass index (BMI), waist, hip, end right upper arm circumferences, and wa ist-to-hip ratio (WHR; an indicator of abdominal adiposity), High levels of WHR were related to an excess risk, with men in the highest quartile WKR > 0.92) having an almost 3-fold risk (OR, 2.71; 95% CI = 1.66-4.41; P-trend = 0.0001) compared with men in the lowest quartile (WHR < 0,86), In contras t, men in the highest quartile of hip circumference (>97.4 cm) had a reduce d risk (OR, 0.46; 95% CI = 0.29-0.74; P-trend = 0.0002) relative to men in the lowest quartile (<86 cm), No association was found for height, usual ad ult weight, or preadult and usual adult BMI, Our results suggest that even in a very lean population (average BMI = 21,9), abdominal adiposity may be associated with an increased risk of clinical prostate cancer, pointing to a role of hormones in prostate cancer etiology, Additional research is need ed to confirm these findings in prospective studies, especially in Western populations where abdominal obesity is much more common, and to clarify the underlying hormonal mechanisms involved.