Frequency of Vitamin D Deficiency in Children: A Single-Center Cross-Sectional Study in Istanbul

Abstract

Aim: Vitamin D deficiency is highly prevalent among children worldwide. This study aims to assess the frequency of vitamin D deficiency in children and how it varies according to gender, age, and season in Istanbul. Material and Method:The study included 3096 children aged 0-18 admitted to the pediatric outpatient clinic in Istanbul. The serum 25 hydroxyvitamin D concentration was analyzed by the High-Performance Liquid Chromatography method using HPLC systems analyzers, and the results were categorized into four groups: deficiency (<20 ng/mL), insufficiency (20-30 ng/mL), sufficiency (30-100 ng/mL), and toxicity (>100 ng/mL). Descriptive methods, Chi-square, Independent Samples T-Test, ANOVA, and correlation test were used in the statistical analysis of the data.Results: Of children, 52% were girls and 48% boys. The mean serum 25 hydroxyvitamin D concentration was 21.8±15.8 ng/mL, and the frequency of vitamin D deficiency was 53.1%. There was a different distribution of vitamin D status between age groups. Vitamin D deficiency was more common in older children. The frequency of vitamin D deficiency was significantly higher in girls than boys (57.6% versus 48.3%). The mean serum 25 hydroxyvitamin D concentration was significantly lower in winter and spring. A moderate negative correlation was found between age and serum 25 hydroxyvitamin D concentration (correlation coefficient:-0.36). Conclusion:This study showed that female sex, older children, and the winter/spring seasons were significantly associated with a higher frequency of vitamin D deficiency and a lower mean serum 25 hydroxyvitamin D concentration.