Correlation of diet and micronutrients with microvascular complications of diabetes mellitus: A Mendelian randomization analysis

Abstract Background Observational studies have found that dietary intake and certain micronutrients are associated with microvascular complications of diabetes. However, the exact causal relationship is unclear. Methods Causal associations of dietary intake and micronutrients with 2 diabetic microvascular complications (diabetic retinopathy and diabetic nephropathy) were explored using two-sample Mendelian randomization analyses, respectively. Genetic data related to dietary intake were obtained from the IEU public database, and genetic data related to micronutrients were obtained from previous genome-wide association studies. Summary statistics for microvascular complications of diabetes were obtained from the FinnGen consortium. Random-effects inverse variance weighted estimation was used as the primary method. Heterogeneity was tested using Cochran's Q statistic. The MR-Egger intercept was used to test for pleiotropy. In addition, we used leave-one-out analysis to test for the presence of SNPs that independently influenced the results. Results Inverse variance weighted estimates suggest coffee intake leads to increased risk of DR [OR = 2.15, 95%CI(1.44–3.20), p = 1.68E-04] and DN [OR = 3.34, 95%CI(1.72–6.46), p = 3.54E-04]. Cheese intake has a protective effect on DR [OR = 0.50, 95%CI(0.34–0.74), p = 4.39E-04]. No significant correlation was observed between micronutrients and two diabetic microvascular complications. Conclusions These findings expose a causal relationship between diet and microvascular complications of diabetes. Coffee intake was associated with an increased risk of DR and DN. Cheese intake was associated with decreased risk of DR.