Prevalence of vitamin D deficiency in exclusively breastfed infants at a tertiary healthcare facility in Nairobi, Kenya

Abstract

Objective: To determine the prevalence of vitamin D deficiency (VDD) in exclusively breastfed infants at the Aga Khan University Hospital Nairobi, Kenya (AKUHN). The relationships between 25-hydroxyvitamin D; 25OHD, parathyroid hormone (PTH), maternal vitamin D supplementation, and sunlight exposure were also determined.

Methods: Blood from 98 infants was assayed for 25OHD, calcium, phosphate, and PTH. Socio-demographic and clinical characteristics were analyzed using descriptive statistics and inferential analysis (p < 0.05).

Results: The prevalence of VDD (25OHD <12 ng/mL), vitamin D insufficiency (VDI, 25OHD 12-20 ng/mL) and vitamin D sufficiency (VDS, 25OHD >20 ng/mL) was 11.2% (95% CI 8.0%-14.4%), 12.2% (95% CI 8.9%-15.5%), and 76.5% (95% CI 72.3%-80.8%) respectively. There was no difference in the mean age, head circumference, length, or weight of infants in VDD, VDI, and VDS groups. PTH was elevated when 25OHD was <12 ng/mL and normal when 25OHD was between 12-20 ng/mL. 25OHD and PTH were normal in infants whose mothers received vitamin D supplements. Infants who received <30 minutes/day of exposure to sunlight were 5 times more likely to have VDI than infants who received ≥30 minutes/day (p = 0.042).

Conclusion: The prevalence of VDD in exclusively breastfed infants at AKUHN is low. The current national policy that recommends exclusive breastfeeding of infants in the first 6 months of life appears to be effective in staving off vitamin D deficiency but those infants with < 30 minutes sunlight exposure may benefit from low dose supplemental vitamin D during times of low sunlight exposure.