Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway,
Eur J Epidemiol. 2013 Nov;28(11):845-58. doi: 10.1007/s10654-013-9852-5. Epub 2013 Oct 25.
Several studies have suggested a protective effect of intake of whole grains, but not refined grains on type 2 diabetes risk, but the dose-response relationship between different types of grains and type 2 diabetes has not been established. We conducted a systematic review and meta-analysis of prospective studies of grain intake and type 2 diabetes. We searched the PubMed database for studies of grain intake and risk of type 2 diabetes, up to June 5th, 2013. Summary relative risks were calculated using a random effects model. Sixteen cohort studies were included in the analyses. The summary relative risk per 3 servings per day was 0.68 (95% CI 0.58-0.81, I(2) = 82%, n = 10) for whole grains and 0.95 (95% CI 0.88-1.04, I(2) = 53%, n = 6) for refined grains. A nonlinear association was observed for whole grains, p nonlinearity < 0.0001, but not for refined grains, p nonlinearity = 0.10. Inverse associations were observed for subtypes of whole grains including whole grain bread, whole grain cereals, wheat bran and brown rice, but these results were based on few studies, while white rice was associated with increased risk. Our meta-analysis suggests that a high whole grain intake, but not refined grains, is associated with reduced type 2 diabetes risk. However, a positive association with intake of white rice and inverse associations between several specific types of whole grains and type 2 diabetes warrant further investigations. Our results support public health recommendations to replace refined grains with whole grains and suggest that at least two servings of whole grains per day should be consumed to reduce type 2 diabetes risk.
几项研究表明，全谷物的摄入对 2 型糖尿病风险有保护作用，但精制谷物则没有，但不同类型谷物与 2 型糖尿病之间的剂量-反应关系尚未确定。我们对谷物摄入量与 2 型糖尿病的前瞻性研究进行了系统评价和荟萃分析。我们在 PubMed 数据库中检索了谷物摄入量与 2 型糖尿病风险的研究，检索截至 2013 年 6 月 5 日。使用随机效应模型计算汇总相对风险。有 16 项队列研究纳入了分析。每天摄入 3 份全谷物的汇总相对风险为 0.68（95%CI 0.58-0.81，I(2) = 82%，n = 10），而精制谷物的汇总相对风险为 0.95（95%CI 0.88-1.04，I(2) = 53%，n = 6）。全谷物呈非线性关联，p 非线性 < 0.0001，但精制谷物则无，p 非线性 = 0.10。全谷物的亚类包括全麦面包、全谷物麦片、麦麸和糙米与 2 型糖尿病呈负相关，但这些结果基于少数研究，而白米则与风险增加相关。我们的荟萃分析表明，高全谷物摄入量与降低 2 型糖尿病风险有关，但与精制谷物无关。然而，白米摄入量与风险增加呈正相关，几种特定类型的全谷物与 2 型糖尿病呈负相关，这需要进一步研究。我们的结果支持用全谷物替代精制谷物的公共卫生建议，并表明每天至少应摄入两份全谷物，以降低 2 型糖尿病的风险。
