Zheng W, Anderson K E, Kushi L H, Sellers T A, Greenstein J, Hong C P, Cerhan J R, Bostick R M, Folsom A R
Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis 55454-1015, USA.
Cancer Epidemiol Biomarkers Prev. 1998 Mar;7(3):221-5.
To investigate whether high intakes of calcium and other micronutrients (carotene, retinol, and vitamins C, D, and E) are related to reduced risks of rectal cancer, we analyzed data from a large cohort study of postmenopausal Iowa women who responded to a mailed survey in 1986. After 9 years of follow-up, 144 incident rectal cancer cases were ascertained among the 34,702 women at risk. Intake levels of micronutrients at baseline were derived from self-reported data on vitamin supplements and dietary intake of 127 foods included in a semiquantitative food frequency questionnaire. After adjustment for total energy intake and other potential confounding factors, a dose-response inverse association was observed between total calcium intake and the risk of rectal cancer: adjusted relative risks (RRs) were 1.00, 0.90, and 0.59 (trend test, P = 0.02) from the lowest to the highest calcium intake tertiles. High intakes of dietary and supplement calcium were both related to a slightly reduced risk of rectal cancer, but neither of the trend tests was statistically significant. Reduced risks of rectal cancer were also observed for high intake of carotene and vitamins A, C, and D, although none of the associations were statistically significant. For vitamin D, the adjusted RRs were 1.00, 0.71, and 0.76 (trend test, P = 0.20) for increasing intake tertiles. Compared with women who consumed low levels of both total calcium and vitamin D, those in the highest intake group of both nutrients were at a 45% reduced risk of rectal cancer (RR, 0.55; 95% confidence interval, 0.32-0.93). This study supports the hypothesis that high intake of calcium and possibly other micronutrients may be beneficial in the prevention of rectal cancer.
为了研究高钙及其他微量营养素（胡萝卜素、视黄醇、维生素C、D和E）的摄入是否与降低直肠癌风险相关，我们分析了来自爱荷华州绝经后女性大型队列研究的数据，这些女性在1986年回复了邮寄调查。经过9年的随访，在34702名有风险的女性中确诊了144例直肠癌新发病例。基线时微量营养素的摄入水平来自于关于维生素补充剂的自我报告数据以及一份半定量食物频率问卷中所包含的127种食物的饮食摄入量。在对总能量摄入和其他潜在混杂因素进行调整后，观察到总钙摄入量与直肠癌风险之间存在剂量反应性负相关：从最低到最高钙摄入量三分位数的调整相对风险（RRs）分别为1.00、0.90和0.59（趋势检验，P = 0.02）。高膳食钙和补充钙的摄入均与直肠癌风险略有降低相关，但两个趋势检验均无统计学显著性。高胡萝卜素、维生素A、C和D的摄入也观察到直肠癌风险降低，尽管这些关联均无统计学显著性。对于维生素D，摄入量增加三分位数的调整RRs分别为1.00、0.71和0.76（趋势检验，P = 0.20）。与总钙和维生素D摄入量均低的女性相比，两种营养素摄入量最高组的女性患直肠癌的风险降低45%（RR，0.55；95%置信区间，0.32 - 0.93）。本研究支持高钙及可能其他微量营养素的摄入在预防直肠癌方面可能有益的假说。
