Association between vitamin D levels and BMI values in an Iranian population

Background: This study aimed to determine the relationship between vitamin D levels and body mass index (BMI) values in a group of Iranian people. Methods: In this cross-sectional study, the anthropometric values and serum vitamin D levels were measured in more than 3500 healthy adults, representing a random sample of the Iranian population in the urban areas of five large cities of Iran. The data used in this study were from the database of the Iranian Multi-centric Osteoporosis Studies (IMOS), previously conducted to assess bone health in the country. The association between BMI values and serum level of 25(OH)D was thereafter calculated. Results: About 46% of the studied 3669 subjects had moderate to severe vitamin D deficiency regardless of their gender. About 43.2% of the overweight individuals and 45.2% of the obese had moderate-to-severe vitamin D deficiency. A linear but weak increasing trend was reported in the serum levels of 25(OH)D based on increasing BMI values. The significance of the value, however, disappeared after the data was adjusted for the possible con-founders. Conclusions: A statistically positive association found between serum levels of 25(OH)D and BMI values raised concerns over the available data, suggesting that more studies should be performed in this regard