Factors associated with vitamin D deficiency in a Norwegian population: the HUNT Study

Vitamin D deficiency occurs worldwide. Winter season and high Body Mass Index (BMI) are associated with low levels of serum 25-hydroxyvitamin D (25(OH)D). We estimated the prevalence of vitamin D deficiency in a Norwegian adult population and examined factors associated with vitamin D deficiency. A cohort of 25 616 adults (19–55 years) who participated in both the second and third Nord-Trøndelag Health Study (HUNT 2 (1995–1997) and HUNT 3 (2006–2008)) was established in a previous study. A 10% random sample of the cohort population was recruited for serum 25(OH)D measurements (n=2584), which was used for the current cross-sectional study. Vitamin D deficiency was defined as serum 25(OH)D level