Patients with hypertension and higher body mass index have tower Vitamin D levels after supplementation

OBJECTIVE To investigate the relation between body mass index (BMI) and Vitamin D level after supplementation with colecalciferol 2000 IE/day for one year. DESIGN Double-blind randomized controlled trial. METHODS Patients with hypertension and low 25(OH)D levels were approached if they met inclusion and not exclusion criteria and had signed informed consent. They were assigned to take either colecalciferol 2000 IE/day or placebo tablets for one year. Participants were checked at baseline, 6 and 12 months. As part of this study we looked at the relation between BMI and 25(OH)D level at 6 and 12 months using a mixed model regression analysis. RESULTS Compared to participants with a normal BMI (18.6-25.0 kg/m2) mean Vitamin D levels were 10 nmol/L lower in participants with a high BMI (25.1-30.0 kg/m2) and 28 nmol/L lower in participants with a very high BMI (> 30.0 kg/m2) after 12 months of supplementation. In participants that took > 80% of the tablets, 94% reached a level > 75 nmol/L after 12 months of supplementation with colecalciferol (n = 35). A BMI rise of 1 kg/m2 correlated with a 1.6 nmol/L lower Vitamin D level after correction for other factors (P = 0.0012). CONCLUSION BMI has a significant influence on the Vitamin D level after supplementation of 2000 IE/day colecalciferol for one year.