Jacobs E J, Connell C J, Patel A V, Chao A, Rodriguez C, Seymour J, McCullough M L, Calle E E, Thun M J
Department of Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia 30329-4251, USA.
Cancer Epidemiol Biomarkers Prev. 2001 Jan;10(1):17-23.
Some recent epidemiological studies have suggested that use of vitamin C or vitamin E supplements, both of which are important antioxidants, may substantially reduce the risk of colon or colorectal cancer. We examined the association between colorectal cancer mortality and use of individual vitamin C and E supplements in the American Cancer Society's Cancer Prevention Study II cohort. We used proportional hazards modeling to estimate rate ratios among 711,891 men and women in the United States who completed a self-administered questionnaire at study enrollment in 1982, had no history of cancer, and were followed for mortality through 1996. During the 14 years of follow-up, 4404 deaths from colorectal cancer occurred. After adjustment for multiple colorectal cancer risk factors, regular use of vitamin C or E supplements, even long-term use, was not associated with colorectal cancer mortality. The combined-sex rate ratios were 0.89 [95% confidence interval (CI), 0.73-1.09] for 10 or more years of vitamin C use and 1.08 (95% CI, 0.85-1.38) for 10 or more years of vitamin E use. In subgroup analyses, use of vitamin C supplements for 10 or more years was associated with decreased risk of colorectal cancer mortality before age 65 years (rate ratio = 0.48; 95% CI, 0.28-0.81) and decreased risk of rectal cancer mortality at any age (rate ratio = 0.40; 95% CI, 0.20-0.80). Our results do not support a substantial effect of vitamin C or E supplement use on overall colorectal cancer mortality.
近期一些流行病学研究表明，服用维生素C或维生素E补充剂（二者均为重要的抗氧化剂）可能会大幅降低患结肠癌或结直肠癌的风险。我们在美国癌症协会的癌症预防研究II队列中，研究了结直肠癌死亡率与单独服用维生素C和E补充剂之间的关联。我们使用比例风险模型，对1982年研究入组时完成一份自填问卷、无癌症病史且随访至1996年死亡率情况的711,89l名美国男性和女性进行了率比估计。在14年的随访期间，有4404人死于结直肠癌。在对多种结直肠癌风险因素进行校正后，规律服用维生素C或E补充剂，即便长期服用，也与结直肠癌死亡率无关。维生素C服用10年及以上的合并性别率比为0.89[95%置信区间(CI)，0.73 - 1.09]，维生素E服用10年及以上的率比为1.08(95%CI，0.85 - 1.38)。在亚组分析中，服用维生素C补充剂10年及以上与65岁之前结直肠癌死亡率风险降低(率比 = 0.48；95%CI，0.28 - 0.81)以及任何年龄直肠癌死亡率风险降低(率比 = 0.40；95%CI，0.20 - 0.80)相关。我们的研究结果不支持服用维生素C或E补充剂对总体结直肠癌死亡率有显著影响。
