Smith LM, et al. – In this randomized placebo-controlled trial, researchers assessed the association of percentage change in bone mineral density with different vitamin D3 doses. Study participants included 163 Caucasian and 31 African American females with serum 25-hydroxyvitamin D (25OHD) ≤ 50 nmol/L who were randomized to placebo, or vitamin D3 400, 800, 1,600, 2,400, 3,200, 4,000, or 4,800 IU/day. Calcium supplements (average 600 mg) were administered to provide a total calcium intake of 1,200 mg/day. The primary endpoint was 12-month serum 25OHD level, which was assessed using ANOVA and Pearson correlations. According to findings, there was no significant impact of daily vitamin D dose (range: 400-4,800 IU/day) on bone mineral density or serum N-terminal telopeptides in this study population of elderly women with initially low serum 25OHD.