Intermittent high-dose vitamin D corrects vitamin D deficiency in adolescents: a pilot study

We aimed to assess the safety and efficacy of high-dose intermittent vitamin D supplementation in adolescents. Twenty-two healthy adolescents with serum 25 hydroxy-vitamin D (25-OHD) of 12.5–50 nmol/l were randomised to receive 300 000 IU or 150 000 IU of vitamin D3, or placebo orally 6-monthly for 1 year. At 12 months, the average vitamin D levels for the 300 000 IU, 150 000 IU and placebo groups were 63.0, 41.1 and 35.8 nmol/l, respectively, (P = 0.004 for difference between 300 000 IU group and placebo after adjustment for age, sex and seasonal variation). At 12 months, one participant receiving 300 000 IU was mildly deficient (25-OHD 49 nmol/l), whereas five out of six (83%) in the placebo and four out of seven participants (57%) in the 150 000 IU group remained deficient. There were no adverse events. Compliance was high. This suggests that 300 000 IU vitamin D3 orally 6-monthly may safely and effectively correct vitamin D deficiency in adolescents.