The prevalence of vitamin D deficiency in iron-deficient and normal children under the age of 24 months

BACKGROUND Iron and vitamin D deficiencies cause a variety of health issues in children, which might have long-lasting effects even in asymptomatic cases. The present study sought to elucidate the potential association between iron status and serum vitamin D levels in infants. METHODS We evaluated 102 infants aged 3-24 months who visited the CHA Bundang Medical Center from August 2010 to July 2011. Questionnaire and laboratory data were collected. The infants were classified into iron deficiency anemia (IDA), iron deficiency (ID), and normal groups according to hemoglobin (Hb) and ferritin levels. They were then classified into vitamin D deficiency (VDD), vitamin D insufficiency (VDI), and vitamin D sufficiency (VDS) groups according to 25-hydroxyvitamin D [25(OH)D] levels. RESULTS VDD was present in 67% of IDA, 53% of ID, and 29% of normal subjects. The proportion of breastfed infants was the highest in the IDA (97%) and VDD (96%) groups. The odds ratio for the likelihood of iron-deficient infants to have subnormal vitamin D levels was 4.115. There was a significant correlation between Hb and 25(OH)D levels. Plasma 25(OH)D levels were lower in the winter/spring. Body mass index values were higher in the IDA/ID groups. Iron, age, and season were predictors of 25(OH)D levels. CONCLUSION The prevalence of iron and vitamin D deficiency was high in breastfed infants. There was also a significant association between Hb and 25(OH)D levels in infants. Since all breastfed infants should receive vitamin D supplementation, there should also be concern about concurrent deficiencies in infants with IDA.