Greenwood Darren C, Threapleton Diane E, Evans Charlotte E L, Cleghorn Christine L, Nykjaer Camilla, Woodhead Charlotte, Burley Victoria J
Corresponding author: Darren C. Greenwood,
Diabetes Care. 2013 Dec;36(12):4166-71. doi: 10.2337/dc13-0325.
Diets with high glycemic index (GI), with high glycemic load (GL), or high in all carbohydrates may predispose to higher blood glucose and insulin concentrations, glucose intolerance, and risk of type 2 diabetes. We aimed to conduct a systematic literature review and dose-response meta-analysis of evidence from prospective cohorts.
We searched the Cochrane Library, MEDLINE, MEDLINE in-process, Embase, CAB Abstracts, ISI Web of Science, and BIOSIS for prospective studies of GI, GL, and total carbohydrates in relation to risk of type 2 diabetes up to 17 July 2012. Data were extracted from 24 publications on 21 cohort studies. Studies using different exposure categories were combined on the same scale using linear and nonlinear dose-response trends. Summary relative risks (RRs) were estimated using random-effects meta-analysis.
The summary RR was 1.08 per 5 GI units (95% CI 1.02-1.15; P = 0.01), 1.03 per 20 GL units (95% CI 1.00-1.05; P = 0.02), and 0.97 per 50 g/day of carbohydrate (95% CI 0.90-1.06; P = 0.5). Dose-response trends were linear for GI and GL but more complex for total carbohydrate intake. Heterogeneity was high for all exposures (I(2) >50%), partly accounted for by different covariate adjustment and length of follow-up.
Included studies were observational and should be interpreted cautiously. However, our findings are consistent with protective effects of low dietary GI and GL, quantifying the range of intakes associated with lower risk. Future research could focus on the type of sugars and other carbohydrates associated with greatest risk.
高血糖指数（GI）、高血糖负荷（GL）或高碳水化合物含量的饮食可能会导致更高的血糖和胰岛素浓度、葡萄糖耐量异常以及2型糖尿病风险。我们旨在对前瞻性队列研究的证据进行系统的文献综述和剂量反应荟萃分析。
我们检索了Cochrane图书馆、MEDLINE、MEDLINE正在处理的文献、Embase、CAB文摘、ISI科学网和BIOSIS，以查找截至2012年7月17日有关GI、GL和总碳水化合物与2型糖尿病风险关系的前瞻性研究。从21项队列研究的24篇出版物中提取数据。使用线性和非线性剂量反应趋势，将使用不同暴露类别的研究合并到同一尺度上。使用随机效应荟萃分析估计汇总相对风险（RR）。
每5个GI单位的汇总RR为1.08（95%CI 1.02 - 1.15；P = 0.01），每20个GL单位为1.03（95%CI 1.00 - 1.05；P = 0.02），每50克/天碳水化合物为0.97（95%CI 0.90 - 1.06；P = 0.5）。GI和GL的剂量反应趋势呈线性，但总碳水化合物摄入量的趋势更为复杂。所有暴露的异质性都很高（I(2)>50%），部分原因是协变量调整和随访时间不同。
纳入的研究为观察性研究，应谨慎解读。然而，我们的研究结果与低饮食GI和GL的保护作用一致，量化了与较低风险相关的摄入量范围。未来的研究可以关注与最大风险相关的糖和其他碳水化合物的类型。
