Résumé
Background and Objectives: vitamin D deficiency/insufficiency is a global health problem. The importance of this problem is doubled in growing children because of their increased need for skeletal growth. This investigation was performed firstly to assess vitamin D status, and secondly to examine its possible relationship with sex, residing area and duration of sun exposure in 9-12 years old children of Tehran
Materials and Methods: we studied 257 randomly selected children out of 1111 children of a huge study, titled "Vitamin D and Calcium Deficiency Prevalence of Tehran's Elementary School Children [VDPT]", performed in fall and winter 2008 in Tehran. The children were without the history of diabetes, allergy or autoimmune disease, and any calcium, vitamin D and fish oil supplement use during the last three months. Venous blood samples were taken, and the sera were analyzed by high performance liquid chromatography [HPLC] for measuring 25-hydroxycalciferol [25[OH] D]
Results: the participating children comprised of 53.7% girls and 46.3% boys from different economical areas of Tehran [40.5% poor, 26% middle and 33.5% rich]. Their mean age was 10.1+/-0.7 years, mean duration of sun exposure was 41.2+/-34.6 min/day, and mean serum 25[OH]D concentration was 21.9+/-15.6 nmol/L. Duration of sun exposure was not significantly different either between boys and girls [p=0.220], among different residing areas [p= 0.057], or between the girls and boys of different areas. The occurrence of vitamin D deficiency was 72.4% [n=186]. Vitamin D status was significantly different between boys and girls [p= 0.01] and among the areas [P= 0.004]. There was no significant relation between poor vitamin D status and duration of sun exposure [p=0.411]
Conclusions: the findings showed a noticeable occurrence of vitamin D deficiency/insufficiency among 9-12 years old children in Tehran. The data warrants urgent interventions