ABSTRACT
Objective: To compare the efficacy of sunlight exposure and oral vitamin D3 supplementation to achieve vitamin D sufficiency in infants at 6 months of age. Design: Open-label randomized controlled trial. Setting: Public hospital in Northern India (28.7°N). Participant: Breastfed infants at 6-8 weeks of age. Intervention: Randomized to receive sunlight exposure (40% body surface area for a minimum of 30 minutes/week) or oral vitamin D3 supplementation (400 IU/day) till 6 months of age. Outcome: Primary - proportion of infants having vitamin D sufficiency (>20 ng/mL). Secondary - proportion of infants developing vitamin D deficiency (<12ng/mL) and rickets in both the groups at 6 months of age. Results: Eighty (40 in each group) infants with mean (SD) age 47.8 (4.5) days were enrolled. The proportion of infants with vitamin D sufficiency increased after intervention in the vitamin D group from 10.8% to 35.1% (P=0.01) but remained the same in sunlight group (13.9%) and was significant on comparison between both groups (P=0.037). The mean (SD) compliance rate was 72.9 (3.4)% and 59.7 (23.6)% in the vitamin D and sunlight group, respectively (P=0.01). The geometric mean (95% CI) serum 25(OH) D levels in the vitamin D and sunlight group were 16.23 (13.58-19.40) and 11.89 (9.93-14.23) ng/mL, respectively; (P=0.02), after adjusting baseline serum 25(OH)D with a geometric mean ratio of 1.36 (1.06-1.76). Two infants in sunlight group developed rickets. Conclusion: Oral vitamin D3 supplementation is more efficacious than sunlight in achieving vitamin D sufficiency in breastfed infants during the first 6 months of life due to better compliance.