Vitamin D Supplementation and High-Density Lipoprotein Cholesterol: A Study in Healthy School Children

Background: The high-density lipoprotein cholesterol (HDL-C) level has been shown to have a significant role in the prevention of cardiovascular diseases and atherosclerosis. Low vitamin D levels have been shown to be correlated with dyslipidemia, but limited data exist on indigenous children. Objectives: We aimed to investigate the effect of vitamin D supplementation on HDL-C levels in school-aged Iranian children. Methods: In this prospective controlled clinical trial, 47 healthy children (23 boys) aged 10 - 14 years, students of Birjand (Iran) elementary schools, were selected and randomly divided into two groups. The study group received a vitamin D supplement (1000 mg capsule) daily for one month, and placebo tablets were prescribed to the controls. Before and after the treatment course, the serum HDL-C and 25-hydroxy vitamin D levels of both groups were measured. The data were analyzed by SPSS, ver. 16, and Chi-square tests, Fisher's exact test, paired-sample t-tests, and Pearson's correlation were used, wherever appropriate. The significance level was set at P < 0.05. Results: Forty children completed the study; their mean age was 11.5 +/- 1.175 years. The mean serum levels of both HDL-C and vitamin D showed a significant rise following the treatment in the study group (P = 0.007 and P < 0.001, respectively), whereas both variables decreased slightly in the control group (P = 0.27). There was no statistically significant difference in the mean serum levels of HDL-C and vitamin D between the two groups after the intervention (P = 0.11 and P = 0.20, respectively). Conclusions: Vitamin D supplements seem to have a positive impact on serum HDL-C levels and may be effective in reducing the risk of cardiovascular diseases in the long term.