A PROSPECTIVE-STUDY OF PLASMA-HORMONE LEVELS, NONHORMONAL FACTORS, AND DEVELOPMENT OF BENIGN PROSTATIC HYPERPLASIA

We assessed the relation of plasma hormone levels and nonhormonal fact ors with subsequent occurrence of surgical treatment for benign prosta tic hyperplasia (BPH) among participants in the Physicians' Health Stu dy. Frozen plasma samples, collected at the study onset, were availabl e for 320 men who developed surgically treated BPH up to 9 years later and for 320 age-matched controls. Plasma testosterone (T), dihydrotes tosterone (DHT), androstenedione, estradiol (E2), and estrone (E1) wer e measured for each case-control pair. In unadjusted analyses, none of the hormones or hormone ratios were associated with BPH; for example, for T and E2 the odds ratios (OR) comparing the highest quintile (Q5) with the lowest (Q1) were 0.74 (95% CI = 0.42, 1.30) and 1.07 (95% CI = 0.51, 2.22), respectively. However, in multivariate analyses contro lling diastolic blood pressure, exercise, alcohol, E1, and DHT:T ratio , we observed a strong trend for increasing risk across quintiles for E2 (Q5 vs. Q1 OR = 3.56, P trend = 0.009), and a weak inverse trend fo r E1 (05 vs Q1 OR = 0.51, P trend = 0.07). The excess risk associated with E2 was confined to men with relatively low androgen levels. Three nonhormonal factors previously suspected as risk factors were indepen dently associated with surgical BPH in these data. The OR for a 1-mm H g difference in diastolic blood pressure was 1.04 (95% CI = 1.01, 1.07 ). Alcohol use and infrequent exercise were inversely associated with risk of BPH surgery; however, risk estimates were not consistent acros s categories of exercise and alcohol frequency. Our results indicate t hat normal variation in circulating androgen levels does not influence development of BPH, but that variation in estrogen levels might be im portant. (C) 1995 Wiley-Liss, Inc.