Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Eur J Clin Nutr. 2012 May;66(5):549-54. doi: 10.1038/ejcn.2011.207. Epub 2011 Dec 14.
BACKGROUND/OBJECTIVE: Previous cohort studies examining the association of serum antioxidant levels and risk of colorectal cancer have used a single (baseline) measurement only. In the present study, we assessed the association of serum levels of eight antioxidant nutrients in relation to risk of colorectal cancer, using repeated measurements.
SUBJECTS/METHODS: Data on a subsample of women in the Women's Health Initiative with repeated measurements of serum retinol, α-carotene, β-carotene, β-cryptoxanthin, lutein+zeaxanthin, lycopene, α-tocopherol and γ-tocopherol during follow-up were included in the analysis. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CIs).
Among 5477 women with baseline serum antioxidant values, 88 incident cases of colorectal cancer were identified over a median follow-up time of 12 years. Serum antioxidants measured at baseline generally showed no association with risk of colorectal cancer, although serum β-carotene at baseline showed a non-significant inverse association with colon cancer alone. Furthermore, using the repeated measurements of β-carotene, the average of all measurements was inversely associated with risk of both colorectal and colon cancer: HRs for highest vs lowest tertile 0.54, 95% CI 0.31-0.96, and 0.47, 95% CI 0.25-0.88, respectively. No associations were seen with other antioxidant nutrients in the repeated measure analyses.
In this study, baseline levels of antioxidant nutrients were not associated with risk of colorectal or colon cancer; however, using repeated measures, a relatively high serum level of β-carotene (average of all measurements) was inversely associated with risk of colon and colorectal cancer in postmenopausal women.
背景/目的：先前的队列研究仅使用单次（基线）测量来检查血清抗氧化剂水平与结直肠癌风险之间的关系。在本研究中，我们使用重复测量评估了八种抗氧化营养素的血清水平与结直肠癌风险之间的关联。
受试者/方法：本分析纳入了 Women's Health Initiative 中女性亚组的重复测量血清视黄醇、α-胡萝卜素、β-胡萝卜素、β-隐黄质、叶黄素+玉米黄质、番茄红素、α-生育酚和γ-生育酚的数据。使用 Cox 比例风险模型估计风险比 (HR) 和 95%置信区间 (CI)。
在基线血清抗氧化剂值的 5477 名女性中，在中位数为 12 年的随访期间，有 88 例结直肠癌发生。基线时测量的血清抗氧化剂通常与结直肠癌风险无关，尽管基线时的血清β-胡萝卜素与结肠癌单独呈负相关，但无统计学意义。此外，使用β-胡萝卜素的重复测量值，所有测量值的平均值与结直肠癌和结肠癌的风险呈负相关：最高与最低三分位的 HR 分别为 0.54（95%CI 0.31-0.96）和 0.47（95%CI 0.25-0.88）。在重复测量分析中，其他抗氧化营养素与风险之间未发现关联。
在这项研究中，基线抗氧化营养素水平与结直肠癌或结肠癌风险无关；然而，使用重复测量值，较高的血清β-胡萝卜素水平（所有测量值的平均值）与绝经后妇女的结肠癌和结直肠癌风险呈负相关。
