Vitamin D for growth and rickets in stunted children:a randomized trial

Background and Objectives: Vitamin D is essential for healthy development of bones but little is known about the effects of supplementation on rickets and linear growth in young stunted children in Afghanistan. The objective was to assess the effect of vitamin D supplementation on risk of rickets and linear growth among Afghan children.Methods: In this double-blind placebo-controlled trial 3,046 children age 1-11 months from inner-city Kabul were randomised to receive oral vitamin D3 (100,000 IU) or placebo every three months for 18 months. Rickets Severity Score was calculated using wrist and knee radiographs for 631 randomly selected infants at 18 months and rickets was defined as a score > 1.5. Weight and length were measured at baseline and 18 months using standard techniques and z-scores calculated.Results: Mean (95% CI) serum 25(OH)D (seasonally-corrected) and dietary calcium intake were insufficient; 37 (35-39) nmol/L and 372 (327-418) mg/d, respectively. Prevalence of rickets was 5.5% (placebo) and 5.3% (vitamin D); OR: 0.96; 95% CI: 0.48-1.92, p=0.9. Mean difference in height-for-age z-score was 0.05, 95% CI: -0.05-0.15, p=0.3, although the effect of vitamin D was greater for those consuming >300mg/day of dietary calcium (0.14; 95% CI: 0-0.29, p=0.05). There was no between-group differences in weight-for-age or weight-for-height z-scores.Conclusions: Except in those with higher calcium intake, vitamin D supplementation had no effect on rickets or growth. This may be because these children were insufficient in both vitamin D and calcium (rather than deficient) and vitamin D was given as a bolus dose