Can correction of low vitamin D status in infancy program for a leaner body composition? A posttrial follow-up study of whole body lean mass in early childhood.

BACKGROUND

Vitamin D supplementation is recommended for infants fed human milk and may have a role in supporting the development of lean body mass.

OBJECTIVE

The main objective was to explore if the effects of 1000 IU/d compared with 400 IU/d of vitamin D3 (cholecalciferol) supplementation in infancy (1-12 mo) on lean body mass were maintained posttrial, ≤36 mo of age.

METHODS

This posttrial follow-up study of a vitamin D supplementation trial (98 infants aged from 1-12 mo in Montréal) included 49 children at 24 mo (400 IU/d: n = 21, 1000 IU/d: n = 28) until early study closure; the coronavirus disease 2019 pandemic precluded reporting at 36 mo and completion of a nonrandomized reference group. The primary outcome was whole body lean mass (dual-energy X-ray absorptiometry). Other outcomes included: serum 25-hydroxyvitamin D [25(OH)D] (immunoassay), measures of anthropometry, and whole body fat mass and bone mineral content (BMC). Developmental milestones were added at 24 mo (Ages and Stages Questionnaire-3). Data were analyzed using linear mixed-effects regression with random intercepts; differences posttrial were tested if the treatment × time interaction was significant.

RESULTS

At 24 mo whole body lean mass [difference: 538.5 g; 95% confidence interval (CI): 44.2, 1032.8 g; P =0.033], BMC (difference: 25.08 g; 95% CI: 2.59, 47.56; P = 0.029), weight (difference: 0.90 kg; 95% CI: 0.17, 1.63; P = 0.016), and length (difference: 2.4 cm; 95% CI: 0.9, 4.0; P = 0.002) were greater in the 1000 IU/d group than the 400 IU/d group. Serum 25(OH)D concentrations, fat mass, and developmental milestones were not significantly different between groups.

CONCLUSIONS

The greater whole body lean mass observed in infants in our published trial of 1000 IU/d of vitamin D supplementation compared with 400 IU/d was maintained posttrial at 24 mo in accordance with greater length. Confirmation of these observations, and whether these extend into later childhood, requires new trials. This trial was registered at clinicaltrials.gov as NCT02563015 (https://www.

CLINICALTRIALS: gov/study/NCT02563015).