Abstract
Introduction: Vitamin D deficiency continues to be a serious public health problem in all age groups in Turkey. The aim of this prospective study was to evaluate the vitamin D status in preschool children after the initiation of support programs and to determine risk factors for vitamin D deficiency.
Materials and Methods: The study included 135 preschool children, >24 months to <84 months of age, who presented to the pediatric clinic between January and September 2018. The demographics, risk factors, diet, and daily vitamin D intake were recorded. Serum levels of 25(OH)D, calcium, phosphorus, and alkaline phosphatase were measured. Serum 25(OH)D levels were evaluated in relation to several risk factors including age, gender, body mass index, number of siblings, socioeconomic status, education level of the family, vitamin D intake during pregnancy and infancy, daily sunlight exposure, and season of presentation.
Results: The mean 25(OH)D level was 19.6±8.5 ng/mL. According to the vitamin D levels, more than half of the children had vitamin D deficiency (n=31, 23%) or insufficiency (n=42, 31.1%). Significantly lower 25(OH)D levels were found in children with low socioeconomic status (p=0.01), a low maternal education level (p=0.02), low regular vitamin D intake during infancy (p=0.04), less daily sunlight exposure (p=0.03), and in those who presented in winter (p=0.01). Laboratory parameters did not differ significantly across the vitamin D deficient, insufficient, and sufficient groups.
Conclusion: Despite the current preventive strategies and supplementation programs, vitamin D deficiency continues to be an important problem not only for risk groups but also for preschool children.

Key words: Vitamin D, deficiency, children, preschool