Baron John A, Cole Bernard F, Mott Leila, Haile Robert, Grau Maria, Church Timothy R, Beck Gerald J, Greenberg E Robert
Department of Medicine, Dartmouth Medical School, , Evergreen Center, Lebanon, NH 03766, USA.
J Natl Cancer Inst. 2003 May 21;95(10):717-22. doi: 10.1093/jnci/95.10.717.
In two large, randomized prevention trials, supplementation with beta-carotene increased the risk of lung cancer. Subjects in these studies were predominantly cigarette smokers, and the adverse effects were concentrated among those who also drank alcohol. Although beta-carotene supplementation appeared not to increase the risk of cancer generally, it is not clear if smoking and/or alcohol use alters the effect of beta-carotene on carcinogenesis at sites outside the lung.
We studied the effect of beta-carotene supplementation on colorectal adenoma recurrence among subjects in a multicenter double-blind, placebo-controlled clinical trial of antioxidants for the prevention of colorectal adenomas. A total of 864 subjects who had had an adenoma removed and were polyp-free were randomly assigned (in a factorial design) to receive beta-carotene (25 mg or placebo) and/or vitamins C and E in combination (1000 mg and 400 mg, respectively, or placebo), and were followed with colonoscopy for adenoma recurrence 1 year and 4 years after the qualifying endoscopy. A total of 707 subjects had two follow-up examinations and provided smoking and alcohol use data. Adjusted multivariate risk ratios (RRs) and 95% confidence intervals (CIs) were used to assess the effects of beta-carotene on adenoma recurrence.
Among subjects who neither smoked cigarettes nor drank alcohol, beta-carotene was associated with a marked decrease in the risk of one or more recurrent adenomas (RR = 0.56, 95% CI = 0.35 to 0.89), but beta-carotene supplementation conferred a modest increase in the risk of recurrence among those who smoked (RR = 1.36, 95% CI = 0.70 to 2.62) or drank (RR = 1.13, 95% CI = 0.89 to 1.43). For participants who smoked cigarettes and also drank more than one alcoholic drink per day, beta-carotene doubled the risk of adenoma recurrence (RR = 2.07, 95% CI = 1.39 to 3.08; P for difference from nonsmoker/nondrinker RR <.001).
Alcohol intake and cigarette smoking appear to modify the effect of beta-carotene supplementation on the risk of colorectal adenoma recurrence.
在两项大型随机预防试验中，补充β-胡萝卜素会增加患肺癌的风险。这些研究中的受试者主要是吸烟者，且不良反应集中在那些也饮酒的人当中。尽管补充β-胡萝卜素总体上似乎不会增加患癌风险，但尚不清楚吸烟和/或饮酒是否会改变β-胡萝卜素对肺部以外部位致癌作用的影响。
在一项多中心双盲、安慰剂对照的抗氧化剂预防结直肠腺瘤的临床试验中，我们研究了补充β-胡萝卜素对受试者结直肠腺瘤复发的影响。共有864名已切除腺瘤且无息肉的受试者被随机分配（采用析因设计）接受β-胡萝卜素（25毫克或安慰剂）和/或维生素C与E联合制剂（分别为1000毫克和400毫克或安慰剂），并在合格内镜检查后1年和4年通过结肠镜检查随访腺瘤复发情况。共有707名受试者接受了两次随访检查并提供了吸烟和饮酒数据。采用调整后的多变量风险比（RR）和95%置信区间（CI）来评估β-胡萝卜素对腺瘤复发的影响。
在既不吸烟也不饮酒的受试者中，β-胡萝卜素与一个或多个复发性腺瘤风险的显著降低相关（RR = 0.56，95% CI = 0.35至0.89），但在吸烟者（RR = 1.36，95% CI = 0.70至2.62）或饮酒者（RR = 1.13，95% CI = 0.89至1.43）中，补充β-胡萝卜素会使复发风险适度增加。对于每天吸烟且饮酒超过一杯的参与者，β-胡萝卜素使腺瘤复发风险加倍（RR = 2.07，95% CI = 1.39至3.08；与不吸烟/不饮酒者RR的差异P <.001）。
饮酒和吸烟似乎会改变补充β-胡萝卜素对结直肠腺瘤复发风险的影响。
