Effectiveness of calcium - vitamin D supplementation on children with abnormal vitamin D status, low BMD, or both in Vietnam

The effects of calcium and vitamin D supplementation on representative factors of bone health have been separately evaluated in different study populations worldwide, however, no data from solely one study population that comprehensively assess the supplementation outcomes on the skeletal system are available. We aimed to evaluate how calcium and vitamin D affect vitamin D level, bone mineral density (BMD), parathyroid hormone (PTH), and bone turnover markers as well as growth parameters in schoolchildren with abnormal vitamin D status and/or low BMD. An uncontrolled trial was carried out on 151 schoolchildren, aged 6-14, recruited from Can Tho City, Vietnam. The subjects were prescribed the combinations of calcium and vitamin D based on their age for a course of 6 months. After the intervention, the concentration of 25OHD was significantly improved (P < 0.001) and only 5.3% of the subjects were found to have an abnormal 25OHD level. Only 10.6%, compared with 66.89% before supplementation, had low BMD after the intervention (P < 0.05). The supplementation also increased weight and height and decreased P1NP. However, no significant changes were observed in β-CTx among boys and in PTH among the two genders. There was a negative correlation between vitamin D level and growth parameter, β-CTx. Linear regression analyses show a significant association between height, β-CTx level, and 25OHD level. In conclusion, the findings from our research provide a comprehensive assessment of various factors affected by calcium-vitamin D supplementation.