Vitamin D supplementation trial in infancy: body composition effects at 3 years of age in a prospective follow-up study from Montréal.

Background: The impact of vitamin D status on body composition is not well understood.
Objectives: Evaluate how vitamin D supplementation in infancy affects body composition at 3 years of age.
Methods: Double-blind randomized trial of 132, 1-month-old healthy, breastfed infants randomly assigned to receive oral vitamin D ₃ supplements of 400, 800, 1200 or 1600 IU d ^-1 for 11 months. In the present analysis, 87 (66%) returned at 3 years of age. Body composition was measured using dual-energy x-ray absorptiometry and plasma 25-hydroxyvitamin D [25(OH)D] concentrations by liquid chromatography tandem mass spectrometry.
Results: Anthropometry, body composition, diet, activity and demographics were similar across dosage groups at 3 years. Mean 25(OH)D concentration from 1 month to 3 years was higher (P < 0.001) in the 1200 IU group than 800 and 400 IU groups. Children with 25(OH)D concentrations above 75 nmol L ^-1 had lower fat mass (~450 g; P = 0.049). In multiple linear regression, mean 25(OH)D was associated with lean mass percent (β = 0.06; CI: 0.00, 0.12; P = 0.042), fat mass (β = -11.29; CI: -22.06, -0.52; P = 0.048) and body fat percent (β = -0.06; CI: -0.12, -0.01; P = 0.045).
Conclusions: Higher vitamin D status from infancy through to 3 years of age associates with leaner body composition.
(© 2016 World Obesity Federation.)