Calcium, vitamin D, and the occurrence of colorectal cancer among women
Calcium, vitamin D, and the occurrence of colorectal cancer among women
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DOI：
10.1093/jnci/88.19.1375
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发表时间：
1996-10-02
影响因子：
10.3
通讯作者：
Willett, WC
中科院分区：
文献类型：
--
作者：
Martinez, ME;Giovannucci, EL;Willett, WC
背景：尽管动物研究表明高钙和维生素D的摄入对结直肠癌有保护作用，但流行病学研究一直没有定论。目的：我们调查了钙和维生素D的摄入与结直肠癌的发生之间的关系，方法：在一项前瞻性研究中，89448名无癌的注册女护士于1980年接受了邮寄的半定量食物频率问卷调查；饮食信息在1984年和1986年更新，到1992年，记录了501例结直肠癌病例(396例结肠癌和105例直肠癌)，作为暴露的衡量标准，我们使用1980年的营养素摄入量和基于三份问卷的两项长期摄入量衡量标准：三份问卷的平均摄入量和持续摄入量，如果女性在所有问卷中处于上三分位数，则定义为高；如果女性在所有问卷中处于低四分位数，则定义为低，以进一步描述长期摄入量。我们排除了1980年前10年中报告牛奶(钙和维生素D的主要来源)摄入量发生变化的妇女，以摄入量的最低五分之一作为参考，计算相对风险(RR)和95%可信区间(CI)，用Mantel扩展检验评估营养摄入量类别之间的线性趋势，在多因素分析中，趋势以摄入量的中位数作为Logistic模型中的连续变量进行检验，趋势的P值是双向的，结果：仅以1980年问卷调查的数据为基础，在排除了报告牛奶摄入量变化的女性后，饮食钙、饮食维生素D(仅来自食物)和总维生素D(来自食物和补充剂)的多变量RR分别为0.80(95%CI=0.60-1.07)、0.84(95%CI=0.63-1.13)和0.88(95%CI=0.66-1.16)。结直肠癌平均摄入量最高和最低的RBS分别为0.74(95%CI=0.36~1.50)、0.72(95%CI=0.34~1.54)和0.42(95%CI=0.19~0.91)，一致性分析的RRS分别为0.70(95%CI=0.35~1.39)、0.59(95%CI=0.30~1.16)。和0.33(95%CI=0.16-0.70)。结论：这些发现并不支持钙摄入量与结直肠癌风险之间存在实质性的负相关，但总维生素D的摄入量与结直肠癌风险之间存在负相关。提示：现有证据不能证明增加钙的摄入量可以预防结肠癌，但需要对钙尤其是维生素D与结直肠癌风险的关系进行更长期的研究。
Background: Despite evidence from animal studies for a protective effect of higher calcium and possibly vitamin D intake against colorectal cancer, epidemiologic studies have been inconclusive, Purpose: We investigated the associations between the intake of calcium and vitamin D and the occurrence of colorectal cancer, Methods: In a prospective study, 89 448 female registered nurses who were free of cancer responded to a mailed, semiquantitative food-frequency questionnaire in 1980; dietary information was updated in 1984 and 1986, Through 1992, 501 incident cases of colorectal cancer (396 colon and 105 rectal cancers) were documented, As measures of exposure, we used nutrient intake in 1980 and also two measures of long-term intake on the basis of the three questionnaires: the average of intakes from the three questionnaires and consistent intakes, which were defined as high if women were in the upper tertile on all questionnaires and low if they were in the lower tertile on all questionnaires, To further characterize long-term intake, we conducted analyses excluding women who reported a change in their consumption of milk (primary source of calcium and vitamin D) in the 10 years prior to 1980, Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using the lowest quintile of intake as a reference, The Mantel extension test was used to evaluate linear trends across the categories of nutrient intake, In multivariate analyses, the trends were tested with use of the medians of the intake as a continuous variable in the logistic model, The P values for the trends were two-sided, Results: On the basis of the data from the 1980 questionnaire alone, the multivariate RR for colorectal cancer for women in the upper versus the lower quintile were 0.80 (95% CI = 0.60-1.07) for dietary calcium, 0.84 (95% CI = 0.63-1.13) for dietary vitamin D (from foods only), and 0.88 (95% CI = 0.66-1.16) for total vitamin D (from foods and supplements), After the exclusion of women who reported a change in their milk intake, the RBs for colorectal cancer for the highest versus the lowest categories of average intake were 0.74 (95% CI = 0.36-1.50) for dietary calcium, 0.72 (95% CI = 0.34-1.54) for dietary vitamin D, and 0.42 (95% CI = 0.19-0.91) for total vitamin D, The corresponding RRs for the consistency analyses were 0.70 (95% CI = 0.35-1.39) for dietary calcium, 0.59 (95% CI = 0.30-1.16) for dietary vitamin D, and 0.33 (95% CI = 0.16-0.70) for total vitamin D, Conclusions: These findings do not support a substantial inverse association between calcium intake and risk of colorectal cancer, but an inverse association between intake of total vitamin D and risk of colorectal cancer was suggested, Implications: Available evidence does not warrant an increase in calcium intake to prevent colon cancer, but longer-term studies of both calcium and especially vitamin D in relation to colorectal cancer risk are needed.