Vitamin D supplementation and cardiometabolic risk factors among diverse schoolchildren: a randomized clinical trial

Background: There remains a lack of evidence demonstrating a potential relationship between vitamin D and cardiometabolic risk among children. Objectives: We examined the effect of 3 different dosages of vitamin D on cardiometabolic risk factors among children at risk of deficiency. Methods: Racially diverse schoolchildren aged 8-15 y were randomly assigned in a double-blind fashion to supplementation with 600, 1000, or 2000 IU vitamin D-3/d for 6 mo. Changes in HDL cholesterol, triglycerides, LDL cholesterol, total cholesterol, and blood glucose over 6 mo and at 12 mo (6 mo post-supplementation) were assessed. Subgroup analyses were also performed by weight status and race. Results: Among 604 children, 40.9% were vitamin D-inadequate at baseline (<20 ng/mL; mean +/- SD: 22.0 +/- 6.8 ng/mL), 46.4% were overweight/obese, and 60.9% had >= 1 suboptimal blood lipids or glucose. Over 6 mo, serum 25-hydroxyvitamin D increased in all 3 dosage groups from baseline (mean +/- SE change: 4.4 +/- 0.6 ng/mL, 5.7 +/- 0.7 ng/mL, and 10.7 +/- 0.6 ng/mL for 600, 1000, and 2000 IU/d, respectively; P < 0.001). Whereas HDL cholesterol and triglycerides increased in the 600 IU group (P= 0.002 and P = 0.02, respectively), LDL cholesterol and total cholesterol decreased across dosage groups. At 6 mo post-supplementation, HDL cholesterol remained elevated in the 600 and 1000 IU groups ( P < 0.001 and P = 0.02, respectively) whereas triglycerides remained elevated in the 1000 and 2000 IU groups (P = 0.04 and P = 0.006, respectively). The suppression of LDL cholesterol and total cholesterol persisted in the 2000 IU group only (P= 0.04 and P< 0.001, respectively). There were no significant changes in blood glucose and similar responses were observed overall by weight status and racial groups across dosages. Conclusions: Vitamin D supplementation demonstrated generally positive effects on HDL cholesterol, LDL cholesterol, and total cholesterol, especially at the lower dosage of 600 IU/d, with several significant changes persisting during the post-supplementation period. Increases in triglycerides across dosage groups may be due to natural changes during adolescence warranting further study.

Automated summary

The study found that vitamin D supplementation had positive effects on HDL cholesterol, LDL cholesterol, and total cholesterol among children at risk of deficiency, especially at the lower dosage. These changes persisted post-supplementation. However, increases in triglycerides across dosage groups may be due to natural changes during adolescence.