Allelic determinants of vitamin d insufficiency, bone mineral density, and bone fractures.

Context: Low 25-hydroxycholecalciferol [25(OH) vitamin D] status is known to play an important role in many diseases with focus on bone health.

Objective: Based on recently reported genetic determinants of vitamin D insufficiency, we aimed to analyze genetic variants of group-specific component (GC), 7-dehydrocholesterol reductase (DHCR7), and cytochrome P450IIR-1 (CYP2R1) for association with vitamin D levels, bone mineral density (BMD), and bone fractures.

Design: We conducted a cross-sectional BMD and fracture study and a prospective cohort study.