Supplementation with 1000 IU vitamin D/d leads to parathyroid hormone suppression, but not increased fractional calcium absorption, in 4-8-y-old children: a double-blind randomized controlled trial.

Study answer

What this study found

Vitamin D3 increased serum 25(OH)D and suppressed PTH, but it did not improve fractional or total calcium absorption over 8 weeks. In the vitamin D3 group, serum 25(OH)D rose from 27.7 6 7.4 ng/mL at baseline to 36.0 6 10.3 ng/mL, while placebo changed from 27.6 6 7.3 to 29.9 6 12.4 ng/mL; the end-of-study between-group difference was significant (P < 0.001). PTH fell from 21.4 6 10.4 pg/mL to 12.9 6 7.1 pg/mL with vitamin D3 versus 18.4 6 10.5 to 17.6 6 10.9 pg/mL with placebo (P < 0.001). End-of-study 1,25(OH)2D did not differ between groups, and no adverse side effects were noted.

Study & population

Double-blind randomized controlled trial in healthy prepubertal children aged 4.0-8.9 years from the Houston area.

Intervention

The active regimen was oral vitamin D3, 1000 IU daily for 8 weeks, formulated in almond oil with orange flavor and matched to placebo in appearance.

Key limitation

The trial was short and included a relatively small sample of healthy children, which limits power and generalizability.

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Original abstract