Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom.
PLoS One. 2013 Sep 2;8(9):e72715. doi: 10.1371/journal.pone.0072715. eCollection 2013.
Prospective studies have consistently reported lower colorectal cancer risks associated with higher intakes of total dairy products, total milk and dietary calcium. However, less is known about whether the inverse associations vary for individual dairy products with differing fat contents.
In the European Prospective Investigation into Cancer and Nutrition (EPIC), we investigated the associations between intakes of total milk and milk subtypes (whole-fat, semi-skimmed and skimmed), yoghurt, cheese, and dietary calcium with colorectal cancer risk amongst 477,122 men and women. Dietary questionnaires were administered at baseline. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusted for relevant confounding variables.
During the mean 11 years of follow-up, 4,513 incident cases of colorectal cancer occurred. After multivariable adjustments, total milk consumption was inversely associated with colorectal cancer risk (HR per 200 g/day 0.93, 95% CI: 0.89-0.98). Similar inverse associations were observed for whole-fat (HR per 200 g/day 0.90, 95% CI: 0.82-0.99) and skimmed milk (HR per 200 g/day 0.90, 95% CI: 0.79-1.02) in the multivariable models. Inverse associations were observed for cheese and yoghurt in the categorical models; although in the linear models, these associations were non-significant. Dietary calcium was inversely associated with colorectal cancer risk (HR per 200 mg/day 0.95, 95% CI: 0.91-0.99); this association was limited to dairy sources of calcium only (HR per 200 mg/day 0.95, 95% CI: 0.91-0.99), with no association observed for non-dairy calcium sources (HR per 200 mg/day 1.00, 95% CI: 0.81-1.24).
Our results strengthen the evidence for a possible protective role of dairy products on colorectal cancer risk. The inverse associations we observed did not differ by the fat content of the dairy products considered.
前瞻性研究一致报告，摄入更多的总乳制品、总牛奶和膳食钙与较低的结直肠癌风险相关。然而，对于不同脂肪含量的个体乳制品，其逆相关关系是否存在差异，这方面的了解较少。
在欧洲癌症前瞻性调查（EPIC）中，我们研究了总牛奶摄入量以及牛奶亚类（全脂、半脱脂和脱脂）、酸奶、奶酪和膳食钙与 477122 名男性和女性结直肠癌风险之间的关系。在基线时进行了饮食问卷。使用 Cox 比例风险模型估计多变量危险比（HRs）和 95%置信区间（CIs），并调整了相关混杂变量。
在平均 11 年的随访期间，发生了 4513 例结直肠癌新发病例。经过多变量调整后，总牛奶的摄入量与结直肠癌风险呈负相关（每天 200 克/天的 HR 为 0.93，95%CI：0.89-0.98）。在多变量模型中，全脂（每天 200 克/天的 HR 为 0.90，95%CI：0.82-0.99）和脱脂牛奶（每天 200 克/天的 HR 为 0.90，95%CI：0.79-1.02）也观察到类似的负相关关系。在分类模型中观察到奶酪和酸奶呈负相关；尽管在线性模型中，这些关联没有统计学意义。膳食钙与结直肠癌风险呈负相关（每天 200 毫克/天的 HR 为 0.95，95%CI：0.91-0.99）；这种关联仅限于乳制品来源的钙（每天 200 毫克/天的 HR 为 0.95，95%CI：0.91-0.99），而非乳制品来源的钙无关联（每天 200 毫克/天的 HR 为 1.00，95%CI：0.81-1.24）。
我们的研究结果加强了乳制品可能对结直肠癌风险具有保护作用的证据。我们观察到的逆相关关系不因所考虑的乳制品的脂肪含量而异。
