Vitamin D deficiency in healthy children and adolescents

Purpose: The aim of this study was to determine vitamin D levels in children and adolescents aged between 2 months and 16 years, and to investigate risk factors leading to deficient or insufficient vitamin D levels. Patients and Methods: One thousand and ten patients from the pediatric clinic of Turgut Ozal University Hospital in Turkey between January 2010 and May 2014 were enrolled in the study. Patients were divided into three groups: 25(OH) vitamin D deficiency, insufficiency and sufficiency according to their 25(OH) vitamin D levels (<= 15 ng/mL, 15-20 ng/mL and >= 20 ng/mL, respectively). 25(OH) Vitamin D levels were measured by HPLC. Results: Approximately a quarter of the children (24.3%) had 25(OH) vitamin D deficiency and 16.5% had 25(OH) vitamin D insufficiency; leaving only (59.2%) of the subjects with sufficient 25(OH) vitamin D levels. Risk factors for 25(OH) vitamin D deficiency were identified by logistic regression analysis using variables of age, gender and season. Logistic regression analysis revealed that winter, spring and autumn seasons and female gender are independent risk factors for 25(OH) vitamin D deficiency/insufficiency (odds ratios: 5.85, 3.93, 1.62 and 1.44, respectively). 25(OH) vitamin D levels decreased as subjects age giving increased odds ratios for subjects aged 13-48 months old (OR: 3.69), 49-108 months old (OR: 4.48) and 109-192 months old (OR: 6.70) compared with 2-12 months old. Conclusion: 25(OH) vitamin D deficiency is a common health problem in childhood. Implementing of 25(OH) vitamin D supplementation should be considered after infancy.