Wu A H, Whittemore A S, Kolonel L N, Stanczyk F Z, John E M, Gallagher R P, West D W
Departments of Preventive Medicine, University of Southern California, Los Angeles, California 90089-0251, USA.
Cancer Epidemiol Biomarkers Prev. 2001 May;10(5):533-8.
Men with higher endogenous 5alpha-reductase activity may have higher prostate cancer risk. This hypothesis raises two questions: (a) Could racial differences in 5alpha-reductase activity explain the observed racial differences in prostate cancer risk? and (b) Could a man reduce his activity level by modifying his lifestyle? To address these questions, we measured two hormonal indices of 5alpha-reductase activity [serum levels of androstane-3alpha-17beta-diol glucuronide (3alpha-diol G) and androsterone glucuronide (AG)] in healthy, older African-American, white, and Asian-American men, who are at high, intermediate, and low prostate cancer risk, respectively. We also examined associations between these metabolite levels and such lifestyle characteristics as body size and physical activity as well as select aspects of medical history and family history of prostate cancer. Men included in this cross-sectional analysis (n = 1054) had served as control subjects in a population-based case-control study of prostate cancer we conducted in California, Hawaii, and Vancouver, Canada and provided information on certain personal attributes and donated blood between March 1990 and March 1992. In this study, concentrations of 3alpha-diol G declined significantly with age and increased significantly with body mass index. Mean levels of 3alpha-diol G, adjusted for age and body mass index, were 6.1 ng/ml in African-Americans, 6.9 ng/ml in whites and 4.8 ng/ml in Asian-Americans. These differences were statistically significant (African-Americans versus whites: P < 0.01; whites versus Asian-Americans: P < 0.001). Concentrations of AG decreased significantly with age, but only in whites, and were unrelated to any of the reported personal attributes. Mean levels of AG, adjusted for age, were 44.1 ng/ml in African-Americans, 44.9 ng/ml in whites, and 37.5 ng/ml in Asian-Americans (Asian-Americans versus whites, P < 0.001). In conclusion, older African-American and white men have similar levels of these two indices of 5alpha-reductase activity, and these levels are higher than those of older Asian-American men. This difference may be related to the lower prostate cancer risk in Asian-Americans.
内源性5α-还原酶活性较高的男性可能患前列腺癌的风险更高。这一假设引发了两个问题：（a）5α-还原酶活性的种族差异能否解释观察到的前列腺癌风险的种族差异？以及（b）男性能否通过改变生活方式来降低其活性水平？为了解决这些问题，我们测量了5α-还原酶活性的两个激素指标[雄烷-3α-17β-二醇葡萄糖醛酸苷（3α-二醇G）和雄酮葡萄糖醛酸苷（AG）的血清水平]，这些指标分别来自健康的老年非裔美国人、白人和亚裔美国人男性，他们患前列腺癌的风险分别为高、中、低。我们还研究了这些代谢物水平与诸如体型和身体活动等生活方式特征以及前列腺癌病史和家族史的某些方面之间的关联。纳入这项横断面分析的男性（n = 1054）曾在我们在加利福尼亚州、夏威夷州和加拿大温哥华进行的一项基于人群的前列腺癌病例对照研究中担任对照受试者，并提供了某些个人属性信息，并在1990年3月至1992年3月期间捐献了血液。在这项研究中，3α-二醇G的浓度随年龄显著下降，随体重指数显著增加。调整年龄和体重指数后，非裔美国人的3α-二醇G平均水平为6.1 ng/ml，白人为6.9 ng/ml，亚裔美国人为4.8 ng/ml。这些差异具有统计学意义（非裔美国人与白人：P < 0.01；白人与亚裔美国人：P < 0.001）。AG的浓度随年龄显著下降，但仅在白人中如此，且与任何报告的个人属性均无关。调整年龄后，非裔美国人的AG平均水平为44.1 ng/ml，白人为44.9 ng/ml，亚裔美国人为37.5 ng/ml（亚裔美国人与白人，P < 0.001）。总之，老年非裔美国人和白人男性这两个5α-还原酶活性指标的水平相似，且这些水平高于老年亚裔美国男性。这种差异可能与亚裔美国人较低的前列腺癌风险有关。
