Reid Mary E, Duffield-Lillico Anna J, Garland Linda, Turnbull Bruce W, Clark Larry C, Marshall James R
Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
Cancer Epidemiol Biomarkers Prev. 2002 Nov;11(11):1285-91.
Interest in the chemopreventive effects of the trace element selenium has spanned the past three decades. Of >100 studies that have investigated the effects of selenium in carcinogen-exposed animals, two-thirds have observed a reduction in tumor incidence and/or preneoplastic endpoints (G. F. Combs and S. B. Combs, The Role of Selenium in Nutrition Chapter 10, pp. 413-462. San Diego, CA: Academic Press, 1986, and B. H. Patterson and O. A. Levander, Cancer Epidemiol. Biomark. Prev., 6: 63-69, 1997). The Nutritional Prevention of Cancer Trial, a randomized clinical trial reported by Clark et al. (L. C. Clark et al., JAMA, 276: 1957-1963, 1996), showed as a secondary end point, a statistically significant decrease in lung cancer incidence with selenium supplementation. The adjusted hazard ratio (HR) was 0.56 [95% confidence interval (CI), 0.31-1.01; P = 0.05]. These results were based on active follow-up of 1312 participants. This reanalysis used an extended Nutritional Prevention of Cancer Trial participant follow-up through the end of the blinded clinical trial on February 1, 1996. The additional 3 years added 8 cases to the selenium-treated group and 4 cases to the placebo group, and increased follow-up to 7.9 years. The relative risk of 0.70 (95% CI, 0.40-1.21; P = 0.18) is not statistically significant. Whereas the overall adjusted HR is not significant (HR = 0.74; 95% CI, 0.44-1.24; P = 0.26), and the HR for current and former smokers was not significant, the trend is toward a reduction in risk of incident lung cancer with selenium supplementation. In a subgroup analysis there was a nominally significant HR among subjects with baseline plasma selenium in the lowest tertile (HR = 0.42; 95% CI, 0.18-0.96; P = 0.04). The analysis for the middle and highest tertiles of baseline showed HRs of 0.91 and 1.25. The current reanalysis indicates that selenium supplementation did not significantly decrease lung cancer incidence in the full population, but a significant decrease among individuals with low baseline selenium concentrations was observed.
对微量元素硒的化学预防作用的关注已持续了过去三十年。在超过100项研究中，有三分之二观察到，在致癌物暴露的动物中，补充硒可降低肿瘤发生率和/或癌前病变终点（G.F.康姆斯和S.B.康姆斯，《硒在营养中的作用》第10章，第413 - 462页。加利福尼亚州圣地亚哥：学术出版社，1986年；以及B.H.帕特森和O.A.莱万德，《癌症流行病学、生物标志物与预防》，6: 63 - 69，1997年）。克拉克等人报告的“营养预防癌症试验”（L.C.克拉克等人，《美国医学会杂志》，276: 1957 - 1963，1996年）作为次要终点显示，补充硒使肺癌发生率有统计学意义的显著下降。调整后的风险比（HR）为0.56 [95%置信区间（CI），0.31 - 1.01；P = 0.05]。这些结果基于对1312名参与者的积极随访。此次重新分析使用了“营养预防癌症试验”参与者的延长随访，直至1996年2月1日盲法临床试验结束。额外的3年使硒治疗组增加了8例病例，安慰剂组增加了4例病例，随访时间延长至7.9年。相对风险为0.70（95% CI，0.40 - 1.21；P = 0.18），无统计学意义。虽然总体调整后的HR不显著（HR = 0.74；95% CI，0.44 - 1.24；P = 0.26），且当前吸烟者和既往吸烟者的HR也不显著，但补充硒有使肺癌发病风险降低的趋势。在亚组分析中，基线血浆硒处于最低三分位数的受试者中，HR有名义上的显著性（HR = 0.42；95% CI，0.18 - 0.96；P = 0.04）。基线处于中间和最高三分位数的分析显示HR分别为0.91和1.25。当前的重新分析表明，补充硒并未使整个人群的肺癌发生率显著降低，但在基线硒浓度低的个体中观察到显著降低。
