Assessment of Vitamin D Status and Response to Vitamin D3 in Obese and Non-Obese Iranian Children

Background: Obesity seems to be a critical issue nowadays because of its high prevalence and its adverse effects on health. There is some evidence indicating the relationship between obesity and lower serum 25-hydroxyvitamin D [25(OH)D] concentration. The aim of the present study was to examine serum 25(OH)D status of obese and non-obese Iranian children and compare their therapeutic response with identical oral vitamin D3 treatment. Methods: In a non-randomized clinical trial, serum 25(OH)D level of 45 obese and 45 non-obese Iranian children aged 2-14 years was measured. Those with serum 25(OH)D status <30 ng/ml (73 cases) were treated with one pearl of vitamin D3 (50 000 International Units) once a week for 6 weeks. Serum vitamin D was measured once more 2 weeks after treatment. Results: The frequency of hypovitaminosis D was 43/45 (95.6%) in obese and 30/45 (66.7%) in non-obese children at baseline (p < 0.001). After treatment of 73 cases (43 obese, 30 non-obese), the above percentages were decreased to 24/43 (55.8%) and 1/30 (3.3%), respectively (p < 0.001). Conclusion: Our study demonstrated a high frequency of vitamin D deficiency among Iranian children, particularly the obese ones. Moreover, low therapeutic response in the obese group is witnessed.