Vitamin D status and risk of type 2 diabetes in the Norwegian HUNT cohort study: does family history or genetic predisposition modify the association?

INTRODUCTION We sought to investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) level and the risk of type 2 diabetes mellitus (T2DM) in adults who participated in the Trondelag Health Study (HUNT), and the possible effect modification by family history and genetic predisposition. RESEARCH DESIGN AND METHODS This prospective study included 3574 diabetes-free adults at baseline who participated in the HUNT2 (1995-1997) and HUNT3 (2006-2008) surveys. Serum 25(OH)D levels were determined at baseline and classified as 0.23). CONCLUSION Serum 25(OH)D<50 nmol/L was associated with an increased risk of T2DM in Norwegian adults. The inverse association was modified by family history of diabetes but not by genetic predisposition to T2DM.