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 Trøndelag 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.