Habitual coffee intake, genetic polymorphisms, and type 2 diabetes

Abstract

BackgroundThe association between coffee intake and type 2 diabetes may be modulated by common genetic variation.ObjectiveThe purpose of this study was to examine the association between habitual coffee intake and the risk of type 2 diabetes and to determine whether this association varied by genetic polymorphisms related to type 2 diabetes in Korean adults.Design and methodsA population-based cohort study over a follow-up of 4 years was conducted. A total of 4077 Korean men and women aged 40–69 years with a normal glucose level at baseline were included. Coffee intake was assessed using a validated food frequency questionnaire, and incident type 2 diabetes or prediabetes was defined by oral glucose tolerance test or fasting blood glucose test. The genomic DNA samples were genotyped with the Affymetrix Genome-Wide Human SNP Array 5.0, and nine single-nucleotide polymorphisms related to type 2 diabetes in East Asian populations were extracted.ResultsA total of 120 cases of type 2 diabetes and 1128 cases of prediabetes were identified. After adjustment for potential confounding factors, we observed an inverse association, but without any clear linear trend, between coffee intake and the combined risk of type 2 diabetes and prediabetes. We found that inverse associations between habitual coffee intake and the combined risk of type 2 diabetes and prediabetes were limited to those with the T-allele (GT/TT) of rs4402960 inIGF2BP2, those with the G-allele (GG/GC) of rs7754840 inCDKAL1, or those with CC of rs5215 inKCNJ11.ConclusionWe found a lower risk of prediabetes and type 2 diabetes combined with coffee intake among individuals with the GT/TT ofIGF2BP2rs4402960, GG/GC ofCDKAL1rs7754840, or CC ofKCNJ11rs5215, which are known to be related to type 2 diabetes in East Asians.