Iranian J Publ Health, 2008, A supplementary issue on Osteoporosis and Bone Turnover, No.1, pp.72-78 72 Vitamin D Deficiency in Iran: A Multi-center Study among Different Urban Areas R Heshmat 1,2 , K Mohammad 2 , SR Majdzadeh 2 , MH Forouzanfar 1,2 , A Bahrami 3 , GH Ranjbar Omrani 4 , I Nabipour 5 , R Rajabian 6 , A Hossein-Nezhad 1 , M Rezaei Hemami 1,2 , AA Keshtkar 7 , M Pajouhi 1 , *B Larijani 1 1 Endocrinology & Metabolism Research Center, Tehran University of Medical Sciences, ran 2 Dept. of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Iran 3 Dept. of Internal Medicine, Tabriz University of Medical Sciences, Iran 4 Endocrine & Metabolism Research Center, Shiraz University of Medical Sciences, Iran 5 Dept. of Internal Medicine, Boushehr University of Medical Sciences, Iran 6 Dept. of Internal Medicine, Mashhad University of Medical Sciences, Iran 7 Dept .of Social Medicine, Medical School, Gholestan University of Medical Sciences, Iran Abstract Background: Recent studies have reported different prevalence of vitamin D deficiency in different sex and age groups in developing countries. In the present survey, we elucidated the prevalence of vitamin D deficiency in a multi-center study among Iranian population. Methods: In a random cluster sample of healthy men and women (ranged 20 to 69 years old), a number of 5232 subjects from five urban metropolitans’ cities (Tehran, Tabriz, Mashhad, Shiraz and Booshehr) were recruited in 2001. Fasting blood sample was taken from participants and sent to the laboratory for measurement of 25-hydroxy vitamin D level. Meta-analy- sis was performed using fixed effect method for estimation of vitamin D deficiency prevalence in a national level. Results: Moderate to severe vitamin D deficiency was estimated in urban areas (except for Booshehr because of its heterogeneity) equal to 47.2, 45.7 and 44.2% in age groups of <50, 50-60 and 60≤ years, respectively among men and 54.2, 41.2 and 37.5 percent among women in the same age groups. The highest prevalence of moderate to severe vitamin D defi- ciency in men was observed in Tehran. Mashhad and Booshehr had also the lowest prevalence of moderate to severe vita- min D deficiency among men and women. Conclusion: Iran is a country with high prevalence of moderate to severe vitamin D deficiency and the prevalence of this deficiency is more evident in Tehran, capital of Iran. Therefore, consideration of main predictors for vitamin D deficiency in all age groups especially in Tehran is recommended. Keywords: Vitamin D, Deficiency, Prevalence, Severity, Urban Introduction Vitamin D has an important role in bone devel- opment and muscle function. It also facilitates absorption of calcium and phosphate from the gut and kidney, suppresses parathyroid hormone (PTH), and acts on osteoblasts to stimulate bone formation. Thus, its deficiency is not only a strong predictor of bone metabolism disturbances, but is also an independent predictor of risk for can- cer and other chronic diseases (1). Vitamin D deficiency is defined as serum 25-Hydroxy vi- tamin D lower than 25 nmol/l (2). Several studies carried out within the two previ- ous decades have shown a high prevalence of vitamin D deficiency in tropical countries such as China, Turkey, India, Iran and Saudi Arabia and estimated its prevalence between 30% and 93% (3-11). Although the role of some factors such as different exposure to sunshine, low die- tary intake of vitamin D and low consumption of supplements has been confirmed as the main ca- uses of this deficiency in these countries (12), the majority of the recent studies have reported different prevalence of vitamin D deficiency in dif- *Corresponding author: Tel: +98 21 84902476, Fax: +98 21 88220037, E-mail: emrc@sina.tums.ac.ir Iranian J Publ Health, 2008, A supplementary issue on Osteoporosis and Bone Turnover, No.1, pp.72-78