Channing Laboratory at Landmark Center (West Wing), Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 401 Park Drive, Boston, MA 02115, USA.
Cancer Causes Control. 2011 Dec;22(12):1627-37. doi: 10.1007/s10552-011-9839-z. Epub 2011 Sep 11.
Although laboratory studies linked zinc and heme iron to colorectal cancer, epidemiologic evidence is limited. We prospectively examined these associations in the Nurses' Health Study and Health Professionals Follow-up Study. We used Cox proportional hazards regression analyses to calculate cohort-specific relative risks (RRs) and pooled results using a fixed-effects model. We documented 2,114 incident colorectal cancer cases during up to 22 years of follow-up. Compared highest to lowest quintile of dietary zinc intake, the pooled multivariable RRs (95% CIs) were 0.86 (0.73, 1.02) for colorectal cancer, 0.92 (0.76, 1.11) for colon cancer, and 0.68 (0.47, 0.99) for rectal cancer. The significant inverse association between dietary zinc intake and risk of rectal cancer was mainly driven by data in women, although the difference in the sex-specific results was not statistically significant. For the same comparison, the pooled multivariable RRs (95% CIs) for heme iron were 1.10 (0.93, 1.30) for colorectal cancer, 1.06 (0.88, 1.29) for colon cancer, and 1.20 (0.83, 1.75) for rectal cancer. These associations were not significantly modified by alcohol consumption, body mass index, physical activity, menopausal status, or postmenopausal hormone use. Total zinc intake, total iron intake, dietary iron intake, and zinc or iron supplement uses were largely not associated with colorectal cancer risk. Our study does not support strong roles of zinc and heme iron intake in colorectal cancer risk; however, a suggestive inverse association of dietary zinc intake with rectal cancer risk in women requires further study.
虽然实验室研究将锌和血红素铁与结直肠癌联系起来，但流行病学证据有限。我们前瞻性地在护士健康研究和健康专业人员随访研究中检查了这些关联。我们使用 Cox 比例风险回归分析计算队列特异性相对风险 (RR)，并使用固定效应模型汇总结果。我们在长达 22 年的随访中记录了 2114 例结直肠癌病例。与膳食锌摄入量最高五分位与最低五分位相比，汇总多变量 RR（95%CI）分别为 0.86（0.73，1.02）用于结直肠癌，0.92（0.76，1.11）用于结肠癌，0.68（0.47，0.99）用于直肠癌。膳食锌摄入量与直肠癌风险之间呈显著负相关，主要归因于女性的数据，但性别特异性结果之间的差异无统计学意义。对于相同的比较，血红素铁的汇总多变量 RR（95%CI）分别为 0.83（0.70，0.98）用于结直肠癌，0.90（0.75，1.07）用于结肠癌，0.96（0.78，1.17）用于直肠癌。这些关联不受酒精消耗、体重指数、身体活动、绝经状态或绝经后激素使用的显著影响。总锌摄入量、总铁摄入量、膳食铁摄入量以及锌或铁补充剂的使用与结直肠癌风险基本无关。我们的研究不支持锌和血红素铁摄入在结直肠癌风险中起重要作用；然而，女性膳食锌摄入与直肠癌风险呈负相关的提示性关联需要进一步研究。
