加拿大安大略省成年人摄入营养素补充剂与结直肠癌发病风险的病例-对照研究

Association between nutrient supplement intake and risk of colorectal cancer: A case-control study of adults in Ontario, Canada

[目的]研究营养素补充剂摄入状况与结直肠癌发病风险的关联。[方法]基于1997年7月1日至2000年6月31日加拿大安大略省结直肠癌症登记系统(Ontario Familial Colorectal Cancer Registry,OFCCR)病例-对照研究,将29~80岁期间确诊患有结肠癌或直肠癌的新发病例作为病例(1 199例),对照来自同期当地居民(1 203例)。收集研究对象基本情况及营养素补充剂使用情况,应用单因素及多因素logistic回归获得比值比(odds ratios,ORs)及其95%可信区间(confidence intervals,CI),评价营养素补充剂摄入状况与结直肠癌发病风险的关联性强度。[结果]研究发现,摄入维生素C(OR=0.77,95%CI:0.64~0.94)、维生素E(OR=0.78,95%CI:0.64~0.95)和钙补充剂(OR=0.78,95%CI:0.62~0.98)是结直肠癌发病的保护因素。每天至少摄入1片维生素C(OR=0.76,P_(趋势)=0.004)、维生素E(OR=0.54~0.79,P_(趋势)=0.007)和钙补充剂(OR=0.64,P_(趋势)=0.005),摄入维生素C(OR=0.61,P_(趋势)=0.001)、维生素E(OR=0.68,P_(趋势)=0.005)和钙补充剂(OR=0.69,P_(趋势)=0.014)连续5年及以上可降低结直肠癌的发病风险;另外,逐步logistic回归结果表明,在排除营养素补充剂相互影响后,摄入维生素C仍可降低结直肠癌的发病风险(OR=0.75,95%CI:0.61~0.91)。[结论]连续5年及以上,每天至少摄入1片维生素C、E和钙补充剂能够降低结直肠癌发病风险。

[Objective] To evaluate the association between nutrient supplement intake and the risk of colorectal cancer.[Methods] A case-control design was employed using information retrieved from the Ontario Familial Colorectal Cancer Registry （OFCCR） from 1 July 1997 to 31 June 2000. We selected cases （n=1 199） who were alive at diagnosis with colon or rectal cancer at the age of 29-80, and recruited controls （n=1 203） in randomly selected households in Ontario. Meanwhile, we collected the in formation of demographic characteristics and nutrient supplement intakes in the cases and controls. Odds ratios （ORs） and 95% confidence intervals （95%CI） of selected supplement intake versus the risk of colorectal cancer were calculated by single factor and multifactor logistic regression.[Results] The intakes of vitamin C （OR=0.77, 95%CI：0.64-0.94）, vitamin E （OR=0.78, 95%CI：0.64-0.95）, and calcium supplements （OR=0.78, 95%CI：0.62-0.98） were protective factors of colorectal cancer. Daily intakes of at least 1 pill of vitamin C （OR=0.76, Ptrend=0.004）, vitamin E （OR=0.54-0.79, Ptrend=0.007）, and calcium supplements （OR=0.64, Ptrend=0.005）, and continuous in takes for at least 5 years of vitamin C （OR=0.61, Ptrend=0.001）, vitamin E （OR=0.68, Ptrend=0.005）, and calcium supplements （OR=0.69, Ptrend=0.014） reduced the risk of colorectal cancer. After controlling for nutrient supplement interactions, the results of stepwise logistic regression showed that intake of vitamin C （OR=0.75, 95%CI：0.61-0.91） reduced the risk of colorectal cancer.[Conclusion] The study findings suggest that intakes of at least 1 pill vitamin C, vitamin E, and calcium supplements for ≥ 5 years continuously could reduce colorectal cancer risk.