Effect of two different doses of oral cholecalciferol supplementation on serum 25-hydroxy-vitamin D levels in healthy Indian postmenopausal women: A randomized controlled trial

AIM: To compare the effect of two different doses (500 and 1000 IU/day) of oral vitamin D3 (cholecalciferol) on serum 25-hydroxy vitamin D [25(OH)D] levels in apparently healthy postmenopausal Indian women. MATERIALS AND METHODS: Serum 25(OH)D, calcium with albumin, phosphorus, and alkaline phosphatase were measured in 92 apparently healthy postmenopausal women. The subjects were randomly assigned to one of the three groups and received supplementation for 3 months each. Each group received 1000 mg calcium carbonate daily while groups B and C received 500 and 1000 IU of cholecalciferol in addition, respectively. The tests were repeated after 3 months. RESULTS: At baseline, 83.7% subjects had vitamin D deficiency (≤20 ng/mL). The difference in the percentage change in mean serum 25(OH)D levels from baseline in group A (–30.5 ± 5.3%), group B (+8.9 ± 19.7%), and in group C (+97.8 ± 53.3%) was statistically significant (P < 0.001) between the three groups. Serum 25(OH)D level >20 ng/mL was achieved in 4.7% (1/21), 16% (4/25), and 66.67% (12/18) subjects in groups A, B, and C, respectively. No significant change was found in serum calcium, phosphorus, and alkaline phosphatase levels at 3 months in either of the groups from baseline. CONCLUSIONS: Standard dose of cholecalciferol available in “calcium tablets” (250 IU per 500 mg calcium carbonate) is not adequate for achieving optimum serum 25(OH)D levels in Indian postmenopausal women. Higher dose of vitamin D supplementation with 1000 IU/day (500 IU per 500 mg calcium carbonate) daily is superior to the standard dose therapy. For achievement of optimum serum 25(OH)D levels (>30 ng/mL) in Indian postmenopausal women, still higher doses of vitamin D are likely to be required.