Vitamin D Supplementation in Women with Vitamin D Receptor Gene Polymorphisms: A Randomized Controlled Trial

Background and Objective: Women living in the tropical regions, including those from North Sumatera, Indonesia, are shown to experience a vitamin D deficiency. Predisposing factors include Vitamin D Receptor (VDR) gene polymorphisms and low vitamin D intakes. The objective of this study was to assess the effect on women with a VDR gene polymorphism (TaqI and BsmI) of 28 days supplementation with 1000 IU vitamin D dayG1 on serum 25-hydroxyvitamin D (25(OH)D) and calcium. Methodalogy: The study was an open parallel-group randomized clinical trial involving 40 women from North Sumatera with a VDR gene polymorphism, recruited using specific criteria. The subjects were divided into two groups of 20 using a randomized block design. The intervention (D) group received 1000 IU vitamin D dayG1 and dietary counseling for 28 days and the control (C) group received a placebo and dietary counseling for 28 days. Serum 25(OH) D and calcium were measured on day 0 and 28. SPSS version 11.5 was used for statistical analysis p<0.05. Results: The study was completed by 19 D group subjects and 17 C-group subjects. The intervention resulted in a significant increase in serum 25(OH) D in the D group (p = 0.04) and no change in serum 25(OH) D the C group. At the end of the intervention, the D group had significantly higher serum 25(OH) D than the C group (p = 0.04) but no subjects with a vitamin D status of deficient or insufficiency were elevated to a status of sufficient from either group. Conclusion: The results revealed that vitamin D deficiency can occur in women with a VDR gene polymorphism even after 28 days supplementation with 1000 IU vitamin D/day.