the epidemic of poor vitamin d status among 9-12 years old children in tehran, 2008, using hplc: need for an urgent action

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. keywords: vitamin d, 25-hydroxycalciferol, school children