Faculty of Medicine, Department of Clinical Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran. Metabolic Syndrome Research center, Mashhad University of Medical Sciences, Mashhad, Iran. Faculty of Medicine, Department of Modern Sciences and Technologies, Mashhad University of Medical Sciences, Mashhad, Iran. Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Departments of Biostatistics and Epidemiology, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran. Brighton & Sussex Medical School, Division of Medical Education, Falmer, Brighton, Sussex BN1 9PH, United Kingdom. Faculty of Medicine, Department of Microbiology, Sabzevar University of Medical Sciences, Sabzevar, Iran.