Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Adv Nutr. 2022 Oct 2;13(5):1787-1798. doi: 10.1093/advances/nmac046.
Despite earlier meta-analyses on the association between adherence to a Mediterranean diet (MD) and risk of diabetes, there is no comprehensive and updated study assessing this issue. Furthermore, no earlier study has examined the nonlinear dose-response relation between consumption of an MD and risk of diabetes. The current systematic review and meta-analysis was conducted to investigate the linear and nonlinear dose-response relation between MD and incidence of diabetes. Using relevant keywords, electronic searches for prospective studies were conducted in ISI Web of Science, PubMed, and Scopus until January 2022. The reported HRs or ORs in the primary studies were regarded as RRs. The overall effect was calculated using a random-effects model that accounts for between-study variability. The potential nonlinear dose-response associations were tested using a 2-stage hierarchical regression model. Based on 16 prospective studies (with 17 effect sizes), we found that the greatest adherence to the MD was significantly associated with a reduced risk of diabetes (pooled RR: 0.83; 95% CI: 0.77, 0.90; I2 = 79%, P ≤ 0.001). Based on linear dose-response analysis, each 1-score increase in the Mediterranean diet score was associated with a 3% decreased risk of diabetes (HR = 0.97; 95% CI: 0.96, 0.98; P < 0.001). A nonlinear relation (P-nonlinearity = 0.001) was also observed between MD score and risk of type 2 diabetes. Even modest adherence to the MD was linked to a decreased incidence of type 2 diabetes. The protocol is also registered in the International Prospective Register Of Systematic Reviews (PROSPERO) database (https://www.crd.york.ac.uk/PROSPERO/; registration ID: CRD 42021265332).
尽管先前有一些荟萃分析研究了地中海饮食（Mediterranean diet，MD）依从性与糖尿病风险之间的关系，但目前尚无综合且最新的研究来评估这一问题。此外，以前的研究也没有探讨 MD 摄入量与糖尿病风险之间的非线性剂量-反应关系。本系统评价和荟萃分析旨在研究 MD 与糖尿病发病率之间的线性和非线性剂量-反应关系。使用相关关键词，在 ISI Web of Science、PubMed 和 Scopus 中进行了前瞻性研究的电子检索，检索时间截至 2022 年 1 月。原始研究中报告的 HR 或 OR 被视为 RR。使用随机效应模型计算总体效应，该模型考虑了研究之间的变异性。使用两阶段分层回归模型检验潜在的非线性剂量-反应关联。基于 16 项前瞻性研究（包含 17 个效应量），我们发现对 MD 最大的依从性与降低糖尿病风险显著相关（汇总 RR：0.83；95%CI：0.77，0.90；I 2 = 79%，P ≤ 0.001）。基于线性剂量-反应分析，地中海饮食评分每增加 1 分，糖尿病风险降低 3%（HR = 0.97；95%CI：0.96，0.98；P < 0.001）。MD 评分与 2 型糖尿病风险之间也观察到非线性关系（P-非线性 = 0.001）。即使对 MD 有适度的依从性，也与 2 型糖尿病发病率的降低有关。该方案也在国际前瞻性系统评价注册库（PROSPERO）（https://www.crd.york.ac.uk/PROSPERO/；注册 ID：CRD 42021265332）中进行了注册。
