Vitamin D status of 6-to 7-year-old children living in Isfahan, Iran

Introduction: Vitamin D is essential for the maintenance of good health, and vitamin D deficiency has been reported from many countries, including those with a lot of sunshine. This study was conducted to evaluate the vitamin D status in healthy 6- to 7-year-old children in Isfahan, Iran. Material and methods: Five hundred and thirteen healthy children were enrolled. Serum PTH and 25-hydroxyvitamin D (25-OHD) were measured. Dietary vitamin D intake, duration of daily sunlight exposure, and percentage of exposed body surface area were determined. 25-OHD levels < 20 ng/mL and < 10 ng/mL were defined as mild and severe vitamin D deficiency, respectively. The ROC curve was utilized to obtain a local cut-off point of vitamin D deficiency. Results: 25-OHD was < 20 ng/mL in 3% and < 33 ng/mL (local cut-off point of vitamin D deficiency) in 26% of subjects. Duration of sunlight exposure and daily intake of vitamin D had significant effects on serum level of vitamin D. Conclusions: A high prevalence of vitamin D deficiency in Isfahan children was observed in this study. Improvements in duration of sunlight exposure and daily intake of vitamin D can prevent vitamin D deficiency in these children. (Pol J Endocrinol 2010; 61 (4): 377-382)