title: Association of dietary vitamin D, serum 25-hydroxyvitamin D, insulin-like growth factor-1 concentrations and components of metabolic syndrome among Iranian women.
abstract: BACKGROUND
  Poor vitamin D status and low serum insulin-like growth factor-1(IGF-1) are associated with metabolic syndrome (MetS) and its components. But, there is no adequate evidence about this. The aim of this study was to examine relationship of factors with MetS features.
  
  
  METHODS
  In this cross-sectional study, 156 women aged 28-76 years with MetS were recruited by consecutive random sampling. Dietary vitamin D, serum 25-hydroxyvitamin D (25(OH) D) and IGF-1 levels and also MetS components were determined.
  
  
  RESULTS
  The mean of serum 25(OH) D and IGF-1 concentrations were 20.5 ± 10.8, 194 ± 47 ng/mL, respectively. Overall, near 54.5% and 24% of subjects were vitamin D deficienct and insufficienct respectively. Univariate regression analysis showed that 25(OH) D concentration was negatively correlated with fasting blood sugar (P < 0.001) and no significant relation was observed between vitamin D status and serum IGF-1 with blood pressure and waist circumference. Multivariate regression analysis showed positive relation of 25(OH) D concentration with HDL-cholesterol (P = 0.031) and also dietary vitamin D is positively correlated with triglyceride (P = 0.026). IGF-1 as a predictor was not related to any of the MetS components.
  
  
  CONCLUSIONS
  Our findings show that vitamin D status was related to FBS, HDL-C and triglyceride concentration; hence, with regard to findings of previous studies it seems that vitamin D is related to components of MetS. However, to determine the role of vitamin D status and IGF-1 in the development MetS and related components, further longitudinal studies and randomized clinical trials should be prescribed.
authors.affiliation: Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Azam Ahmadi
authors.initials: AA
authors.lastname: Vasmehjani
authors.affiliation: Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran ; Department of Clinical Nutrition, Faculty of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Zamzam
authors.initials: Z
authors.lastname: Paknahad
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Maracy
keywords: IGF-1; metabolic syndrome; nutrition; vitamin D