Association of Serum 25-Hydroxyvitamin D Levels and Vitamin D Dietary Intake with Metabolic Syndrome: A Case Control Study

Background: Association between the vitamin D deficiency and metabolic syndrome (MetS) has previously been noted and reported to be controversial. The aim of this study was to determine the association of serum 25 (OH) D Level and Vitamin D dietary intake with MetS among Iranian population. Methods: This analytical study was conducted on 122 patients with MetS based on the ATPIII criteria and 128 subjects without MetS as control from September 2010 to April 2011. Serum levels of calcium, phosphorus and 25(OH) D were compared between the two groups. A food frequency questionnaire (FFQ) was used to calculate dietary intake. Data were analyzed using Chi-square test, t-test, Mann-Whitney U test and logistic regression analysis. Results: Serum concentrations of 25 (OH) D, calcium and phosphorus and calcium intake were significantly lower in subjects with MetS compared to the subjects without MetS. 98.4% of subjects with MetS and 88.3% without MetS had Vit. D deficiency and this difference was statistically significant (P=0.005). In regression analysis, lower concentration of serum 25 (OH) D, calcium and phosphorus and lower calcium and diary intake were predictors of MetS. Conclusions: Serum 25 (OH) D Level, calcium and phosphorus and calcium intake are associated with metabolic syndrome. However, the mechanism of this association requires further studies.