The prevalence and determinants of vitamin D deficiency in indonesian infants at birth and six months of age

Background Vitamin D deficiency in infants has been associated with an increased risk of a number of diseases but there are limited data on the prevalence and determinants of vitamin D deficiency from tropical settings with high infant morbidity and mortality. Objective To determine the prevalence and determinants of vitamin D deficiency in infants at birth and at six months of age in Yogyakarta province, Indonesia. Design Serum vitamin D of eligible infants was measured in cord blood at birth and at six months of age. Factors associated with vitamin D deficiency (serum 25-hydroxyvitamin D <50 nmol/L) were collected prospectively monthly from birth and concentrations measured by liquid chromatography-tandem mass spectrometry. Independent risk factors were identified by multiple logistic regression. Results Between December 2015 to December 2017, 350 maternal-newborn participants were recruited and followed up. Vitamin D deficiency was detected in 90 (308/344) of cord blood samples and 13 (33/255) of venous blood samples at six months. Longer time outdoors (>2 hours per day) and maternal multivitamin intake containing vitamin D during pregnancy were protective against vitamin D deficiency at birth (AOR: 0.10, 95 CI: 0.01�0.90 and AOR: 0.21, 95 CI: 0.06�0.68, respectively). Risk factors for vitamin D deficiency at six months included lower cumulative skin-sun exposure score (AOR: 1.12, 95 CI: 1.04�1.20), severe vitamin D deficiency at birth (AOR: 7.73, 95 CI: 1.20�49.60) and exclusive breastfeeding (AOR: 2.64, 95 CI: 1.07�6.49) until six months. Among exclusively breast fed (EBF) infants, a higher skin-sun exposure score was associated with reduced vitamin D deficiency risk. Conclusion In equatorial regions, the role of �safe� morning sun exposure in infants and mothers in populations with medium to dark brown skin pigmentation and effective interventions to prevent vitamin D deficiency in newborns and EBF infants, need further consideration and evaluation. © 2020 Elsevier B.V., All rights reserved.