Effects of weekly cholecalciferol supplementation of lactating mothers on vitamin D status, and infant growth and gross motor development: a randomized controlled trial in rural Ethiopia

Abstract

Background: Vitamin D plays crucial roles in bone metabolism, growth, and immune response during critical life stages. There is little evidence on the effects of vitamin D supplementation among lactating mothers and their infants in sub-Saharan Africa.

Objective: We aimed to evaluate the efficacy of maternal vitamin D supplementation during lactation on maternal and infant vitamin D status, biomarkers of bone turnover, and infant anthropometry and motor development in rural Ethiopia.

Methods: In an individually randomized placebo-controlled trial, 126 mothers <2 wk postpartum were allocated to receive either weekly vitamin D₃ (15,000 IU cholecalciferol) or placebo capsules for 12 mo. Primary outcomes were maternal and infant plasma 25-hydroxy vitamin D (25(OH)D) concentrations and infant clinical diagnosis for "suspected rickets." Secondary outcomes included biomarkers of bone metabolism, such as maternal plasma concentrations of parathyroid hormone, cross-linked telopeptide type 1 collagen, osteocalcin, and bone-specific alkaline phosphatase (BAP), infant plasma BAP, and maternal urinary concentrations of calcium, phosphorus, and calcium/creatinine ratio. Additional secondary outcomes included infant growth and motor development.

Results: Compared with the placebo, weekly cholecalciferol supplementation resulted in greater increases in maternal plasma 25(OH)D concentration at 6 mo [76.6% (95% CI: 56.2, 99.7%); P < 0.001] and 12 mo [68.8% (95% CI: 49.5, 90.7%); P < 0.001]. Maternal vitamin D supplementation also led to significantly higher infant plasma 25(OH)D concentration at 12 mo compared with the placebo group [14.7 nmol/L (95% CI: 5.29, 24.1 nmol/L; P = 0.003)]. There were nonstatistically significant fewer 'suspected rickets' cases in the vitamin D group (8.00%) than the placebo (15.4%) at 12 mo (P = 0.284). However, no significant group differences were observed in infant growth and development.

Conclusions: Maternal cholecalciferol supplementation during lactation using a weekly dose of 15,000 IU safely improves both maternal and infant vitamin D status. The trial was registered at clinicaltrials.gov as NCT02210884.

Keywords: infants; lactating mothers; low-income setting; tropical region; vitamin D supplementation.