Vogt Tara M, Ziegler Regina G, Graubard Barry I, Swanson Christine A, Greenberg Raymond S, Schoenberg Janet B, Swanson G Marie, Hayes Richard B, Mayne Susan T
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892-7246, USA.
Int J Cancer. 2003 Feb 20;103(5):664-70. doi: 10.1002/ijc.10866.
Prostate cancer is the fourth most common cancer in men worldwide and the most common cancer in men in the United States, with reported incidence rates for U.S. blacks being the highest in the world. The etiology of prostate cancer and an explanation for the racial disparity in incidence in the United States remain elusive. Epidemiologic studies suggest that selenium, an essential trace element, may protect against the disease. To further explore this hypothesis, we measured serum selenium in 212 cases and 233 controls participating in a multicenter, population-based case-control study that included comparable numbers of U.S. black and white men aged 40-79 years. Serum selenium was inversely associated with risk of prostate cancer (comparing highest to lowest quartiles, OR = 0.71, 95% CI 0.39-1.28; p for trend = 0.11), with similar patterns seen in both blacks and whites. Cubic regression spline analysis of continuous serum selenium indicated a reduced risk of prostate cancer above concentrations of 0.135 microg/ml (median among controls) compared to a reference value set at the median of the lowest selenium quartile. Because both the selenoenzyme GPX and vitamin E can function as antioxidants, we also explored their joint effect. Consistent with other studies, the inverse association with selenium was strongest among men with low serum alpha-tocopherol concentrations. In conclusion, our results suggest a moderately reduced risk of prostate cancer at higher serum selenium concentrations, a finding that can now be extended to include U.S. blacks. Since selenium exposure varies widely throughout the world, further research on optimal concentrations for cancer prevention is justified.
前列腺癌是全球男性中第四大常见癌症，在美国则是男性中最常见的癌症，据报道美国黑人的发病率为世界最高。前列腺癌的病因以及美国发病率存在种族差异的原因仍不清楚。流行病学研究表明，必需微量元素硒可能预防这种疾病。为了进一步探讨这一假设，我们在一项多中心、基于人群的病例对照研究中，对212例病例和233例对照者的血清硒进行了测量，该研究纳入了数量相当的40至79岁美国黑人和白人男性。血清硒与前列腺癌风险呈负相关（最高四分位数与最低四分位数相比，OR = 0.71，95% CI 0.39 - 1.28；趋势p值 = 0.11），黑人和白人中均观察到类似模式。对血清硒连续值进行三次回归样条分析表明，与设定为最低硒四分位数中位数的参考值相比，血清硒浓度高于0.135微克/毫升（对照者中位数）时前列腺癌风险降低。由于硒酶GPX和维生素E都可作为抗氧化剂发挥作用，我们还探讨了它们的联合作用。与其他研究一致，血清α-生育酚浓度低的男性中，与硒的负相关最强。总之，我们的结果表明，血清硒浓度较高时前列腺癌风险适度降低，这一发现现在可推广至美国黑人。由于世界各地的硒暴露差异很大，因此有必要进一步研究预防癌症的最佳浓度。
