Satia-Abouta Jessie, Galanko Joseph A, Martin Christopher F, Potter John D, Ammerman Alice, Sandler Robert S
Department of Nutrition, School of Public Health, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA.
Cancer Epidemiol Biomarkers Prev. 2003 Aug;12(8):747-54.
African Americans have the highest incidence of colon cancer among United States racial/ethnic groups, but these disparities are largely unexplained. This report describes associations of micronutrients with colon cancer risk in African Americans and whites using data from a case-control study in North Carolina. Incident cases of histologically confirmed colon cancer, age 40-80 years (n = 613), and matched controls (n = 996) were interviewed in person to elicit information on potential colon cancer risk factors. A previously validated food frequency questionnaire adapted to include regional foods was used to assess diet over the year prior to diagnosis or interview date. Micronutrient exposure included food sources and dietary supplements. Multivariate logistic regression models estimated energy-adjusted and non-energy-adjusted odds ratios (ORs). African Americans reported lower mean micronutrient intakes than whites, primarily due to larger contributions from dietary supplements in whites. Controls generally reported higher micronutrient intakes than cases; however, these differences were only statistically significant for whites. In whites, high beta-carotene, vitamin C, and calcium intakes were associated with 40-60% reductions in colon cancer risk when contrasting highest to lowest quartiles in both energy-adjusted and non-energy-adjusted models, e.g., OR = 0.4 (95% confidence interval, 0.3-0.6) for the highest quartile of calcium in the energy-adjusted model. In African Americans, vitamins C and E were strongly inversely associated using both statistical approaches: high vitamin E intake was associated with a 70% reduced risk for colon cancer, and the OR comparing the highest to lowest quartiles of vitamin C was 0.5 (95% confidence interval, 0.3-0.8). Folate and lutein were not statistically significantly associated with colon cancer risk in either racial group. These results suggest that at high intakes, micronutrients commonly found in plant and other foods (in particular, beta-carotene, vitamin C, and calcium in whites and vitamins C and E in African Americans) exhibit independent associations consistent with 30-70% reductions in colon cancer risk.
非裔美国人在美国各种族/族裔群体中患结肠癌的发病率最高，但这些差异在很大程度上尚无法解释。本报告利用北卡罗来纳州一项病例对照研究的数据，描述了非裔美国人和白人中微量营养素与结肠癌风险之间的关联。对年龄在40至80岁之间经组织学确诊的结肠癌新发病例（n = 613）和匹配的对照者（n = 996）进行了面对面访谈，以获取有关潜在结肠癌风险因素的信息。使用一份先前经过验证且适用于纳入当地食物的食物频率问卷来评估诊断或访谈日期前一年的饮食情况。微量营养素暴露包括食物来源和膳食补充剂。多变量逻辑回归模型估计了能量调整和非能量调整的比值比（OR）。非裔美国人报告的平均微量营养素摄入量低于白人，主要原因是白人从膳食补充剂中摄入的量更大。对照者通常报告的微量营养素摄入量高于病例组；然而，这些差异仅在白人中具有统计学意义。在白人中，将能量调整和非能量调整模型中最高四分位数与最低四分位数进行对比时，高β-胡萝卜素、维生素C和钙的摄入量与结肠癌风险降低40%-60%相关，例如，在能量调整模型中，钙最高四分位数的OR = 0.4（95%置信区间，0.3-0.6）。在非裔美国人中，使用两种统计方法均显示维生素C和维生素E与结肠癌风险呈强烈负相关：高维生素E摄入量与结肠癌风险降低70%相关，维生素C最高四分位数与最低四分位数的OR为0.5（95%置信区间，0.3-0.8）。在两个种族群体中，叶酸和叶黄素与结肠癌风险均无统计学显著关联。这些结果表明，在高摄入量时，植物和其他食物中常见的微量营养素（特别是白人中的β-胡萝卜素、维生素C和钙以及非裔美国人中的维生素C和维生素E）呈现出与结肠癌风险降低30%-70%一致的独立关联。
