495 - Vitamin D supplementation and multiple health outcomes: a phase 3 randomized trial of vitamin D supplementation in 8,851 Mongolian schoolchildren

Poster Number: 495
Publication Number: 495.100

Davaasambuu Ganmaa, Harvard School of Public Health, Boston, MA, United States

Background: Experts debate optimal 25-hydroxyvitamin D (25[OH]D) levels for healthy growth and body composition, and the role of vitamin D supplementation in improving growth and development in children and adolescents is uncertain.

Objective: To determine the effects of vitamin D supplementation on diverse health outcomes in vitamin D-deficient schoolchildren. 

Design/Methods: We performed a phase 3 randomized placebo-controlled clinical trial in Ulaanbaatar, Mongolia, to determine whether weekly oral supplementation with 14,000 IU vitamin D3, administered for 3 years, will influence a range of health outcomes and growth and development in 8,851 schoolchildren aged 6 to 13 years. Sub-studies evaluated effects of the intervention on bone mineral density (n=1,465) and spirometry (n=1,465), physical fitness (n=615), Tanner stage (n=1,387) and math test scores (Nf2,134). Safety outcomes included mortality and incidence of serious adverse events. Sub-group analyses and analyses were conducted for all efficacy outcomes to determine whether the effect of the intervention varied according to baseline 25-hydroxyvitamin D levels and calcium intake).

Results: Of the 8,851 randomized participants, 95.6% had vitamin D deficiency (25[OH]D < 20 ng/mL) at baseline, and 91.7% completed the study. Mean end-study 25(OH)D levels were 29.8 vs. 9.7 ng/mL in children randomized to intervention vs. placebo (p < 0.001). Vitamin D supplementation did not influence the risk of latent TB infection acquisition (P=0.42), incident active TB (P=0.63), incident asthma (P=0.32), incident allergic rhinitis (P=0.45) and atopic dermatitis (P=0.39),mean forced expiratory volume in 1 second (FEV1, P=0.35), mean forced vital capacity (FVC, P=0.95), mean maximal oxygen consumption during a 20 meter shuttle run (VO2max, P=0.22), incidence of fracture (p=0.65), mean radial BMD z-score (n=0.14), mean height for age Z-score (p=0.84), mean BMI for age Z-score (p=0.75), mean Tanner score for pubic hair (p=0.52), mean grip strength (p=0.77), mean long jump distance (p=0.23) or mean math exam score (p=0.57). Effects of the intervention did not differ according to baseline 25-hydroxyvitamin D levels ( < 10 ng/mL vs. ≥10 ng/mL) for any efficacy outcome studied in subset population. Neither mortality nor incidence of serious adverse events differed between study arms.
 Conclusion(s): A weekly oral dose of 14,000 IU (3.5 mg) vitamin D3, administered for 3 years, was safe and effective in elevating 25-hydroxyvitamin D levels into the high physiological range in vitamin D-deficient schoolchildren, but it did not affect any efficacy outcome investigated.
Consort diagram
Baseline Characteristics