Prevalence of vitamin D deficiency among Iranian adolescents.

OBJECTIVE: Despite the high prevalence of vitamin D deficiency in adults worldwide, not many studies have evaluated the condition in adolescents. The present study was therefore conducted to assess the prevalence of vitamin D deficiency in a group of students from Shahroud, Iran. METHODS: The cross-sectional descriptive analytical study was conducted on junior high and high school students of both genders from urban and rural areas of Shahroud, the largest city of Semnan Province in Iran, in winter 2011. The combination of stratified and cluster random sampling methods was applied in the study. A questionnaire on the demographic data, socioeconomic status, lifestyle habits (sun exposure, physical activity, dairy consumption), and drug and personal history was completed for each student. Blood samples were taken to assess vitamin D levels. RESULTS: One thousand forty-seven students from four junior high and six high schools were recruited. From among them, 42.2% were boys and 57.8% were girls. Mean and standard deviation of vitamin D levels in the studied population were 14.7 ± 9.4 ng/mL. Only 7.2% of the boys and 3.8% of the girls had sensible sun exposure. The median of milk consumption was 3 glasses per week, ranging from 0 to 7. CONCLUSION: It could be concluded that vitamin D deficiency is quite prevalent among the Iranian adolescents, and this is mainly because this group follows an unhealthy lifestyle due to osteoporosis.