The role of vitamin D and osteocalcin on diabetic macrovascular and microvascular events in the field study

Abstract

Objective People with diabetes frequently develop vascular disease, and accumulating evidence suggests a coupled interaction between bone turnover and glycaemic control. We investigated the relationship between blood 25-hydroxy vitamin D (25OH-D) and osteocalcin (OCN) concentration on vascular disease risk in type 2 diabetes. Research design and methods The relationships between blood 25OH-D and OCN concentration at baseline and the incidence of macrovascular (including myocardial infarction, stroke) and microvascular (retinopathy, nephropathy, neuropathy, and amputation) disease were analysed with Cox proportional-hazards models and logistic regression in an observational study of patients in the 5-year Fenofibrate Intervention and Event Lowering in Diabetes trial. Results 50% of the patients low 25OH-D concentrations, as indicated by median blood 25OH-D concentration of 49nmol/L. These patients with a blood 25OH-D concentration < 50nmol/L had a higher cumulative incidence of macrovascular and microvascular events than those with levels ≥ 50nmol/L. Patients with OCN levels below the population mean of 9.1 ng/mL show a significantly higher cumulative incidence of microvascular events than those with ≥ 9.1 ng/mL. Higher baseline serum OCN was associated with a reduction in risk of microvascular events of 8% per 5ng/mL. Undercarboxylated OCN was not a significant predictor of micro- or macrovascular events. Multivariate analysis, stratified by treatment and adjusted for relevant confounders, identified blood 25OH-D and OCN concentration as an independent predictor of macrovascular and microvascular events.