Insulin-Like Growth Factor Binding Protein 2 (IGFBP-2) and the Risk of Developing Type 2 Diabetes

Recent studies suggest that insulin-like growth factor binding protein-2 (IGFBP-2) may protect against type 2 diabetes but population-based human studies are scarce. We aimed to investigate the prospective association of circulating IGFBP-2 concentrations and of differential methylation in the IGFBP-2 gene with type 2 diabetes risk. Within the EPIC-Potsdam cohort (n=27,548), circulating IGFBP-2 concentration was assessed in a nested case-cohort (random subcohort, n=2500, all incident type 2 diabetes cases, n=820). A nested 1:1 matched case-control sample (300 incident type 2 diabetes cases, 300 controls) was constructed for DNA-methylation profiling. Longitudinal associations were evaluated in Cox models (case-cohort) and conditional logistic models (case-control), adjusting for age, sex, anthropometry, lifestyle and a large set of type 2 diabetes-related biomarkers. Higher circulating IGFBP-2 concentrations (median 92 ng/mL) were cross-sectional linked to lower BMI, waist circumference, fatty liver index, triglycerides, fetuin A, ALT and γ-GT, and longitudinal associated with lower type 2 diabetes risk (HR per SD 0.65, 95%CI 0.53, 0.8). A methylation score based on seven type 2 diabetes-related CpGs in the IGFBP-2 gene was associated with higher type 2 diabetes risk (OR per SD 2.7, 95%CI 2.1, 3.5). Our results are consistent with a type 2 diabetes-protective effect of high circulating IGFBP-2 concentration, and suggest that epigenetic silencing of the IGFBP-2 gene might predispose for type 2 diabetes.