The association of dietary insulin and glycemic indices with the risk of type 2 diabetes

Background and aim: The aim of this study was to investigate the association of dietary insulin index(II), insulin load(IL), glycemic index(GI), and glycemic load(GL) with risk of developing diabetes among the Tehranian adults. Methods: This study was conducted within the framework of the Tehran Lipid and Glucose Study on 1149 subjects, aged �30 years, who were followed-up for a mean of 8.04 years. Food frequency questionnaire was used to calculate the dietary GI, GL, II, IL at the baseline. Multivariate Cox proportional hazard regression models, adjusted for the potential confounders, were used to estimate the risk of diabetes based on the dietary indices. Results: Mean age of the study population was 44.8 ± 10.4 years and 46.3 of them were men. During a mean of 8.04 ± 2.1 years of follow-up, 76 (6.6) new cases of diabetes were identified. The mean ± SD of the II, IL, GI, and GL of the participants were 52.4 ± 6.5, 234.9 ± 88.8, 61.8 ± 7.9, and 200.6 ± 74.5, respectively. After adjusting for age, sex, smoking, physical activity, daily energy intake, and body mass index, higher dietary scores of the IIHR = 1.33 (95%CIs = 1.06�1.68), ILHR = 1.70(95%CIs = 1.10�2.60), GIHR = 1.28(95%CIs = 1.03�1.60), and GLHR = 1.84 (95%CIs = 1.19�2.84) were found to be associated with the increased risk of diabetes incidence per each ones SD increment in the scores. Considering the tertiles of the dietary scores, the risk of developing diabetes was increased significantly from tertile 1 into 3 of the GL, and after adjusting for all the potential covariates (p-trend = 0.002); the diabetes risk was 3.40 (95%CI:1.48�7.83) in those with highest tertile of GL compared to those in the lowest tertile of GL. Conclusion: Our findings suggest that the diet with high GL, GI, II, and IL can increase the incidence of diabetes. The glycemic and insulin load can strongly predict the risk of diabetes rather than the glycemic index and insulin index. © 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolis