Sunlight exposure or vitamin D supplementation for vitamin D-deficient non-western immigrants: a randomized clinical trial.

Osteoporos Int. 2010 Aug 4.
Wicherts IS, Boeke AJ, van der Meer IM, van Schoor NM, Knol DL, Lips P.
EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.

Vitamin D deficiency is very common in non-western immigrants. In this randomized clinical trial, vitamin D 800 IU/day or 100,000 IU/3 months were compared with advised sunlight exposure. Vitamin D supplementation was more effective than advised sunlight exposure in improving vitamin D status and lowering parathyroid hormone levels.

INTRODUCTION: Vitamin D deficiency (25-hydroxyvitamin D 25(OH)D < 25 nmol/l) is common among non-western immigrants. It can be treated with vitamin D supplementation or sunlight exposure.

METHODS: To determine whether the effect of vitamin D(3) supplementation (daily 800 IU or 100,000 IU/3 months) or sunlight exposure advice is similar with regard to serum 25(OH)D and parathyroid hormone (PTH) concentrations. Randomized clinical trial in 11 general practices in The Netherlands. Non-western immigrants, aged 18-65 years (n = 232) and serum 25(OH)D < 25 nmol/l were randomly assigned to supplementation (daily 800 IU or 100,000 IU/3 months) or advice for sunlight exposure for 6 months (March-September). Blood samples were collected at baseline, during treatment (3 months, 6 months), and at follow-up (12 months). Statistical analysis was performed with multilevel regression modelling.

RESULTS: The intention-to-treat analysis included 211 persons. Baseline serum 25(OH)D was 22.5 +/- 11.1 nmol/l. After 6 months, mean serum 25(OH)D increased to 53 nmol/l with 800 IU/day, to 50.5 nmol/l with 100,000 IU/3 months, and to 29.1 nmol/l with advised sunlight exposure (supplementation vs sunshine p < 0.001). Serum PTH decreased significantly in all groups after 3 months, more in the supplementation groups than in the advised sunlight group (p < 0.05). There was no significant effect on physical performance and functional limitations.

CONCLUSION: Vitamin D supplementation is more effective than advised sunlight exposure for treating vitamin D deficiency in non-western immigrants. PMID: 20683712