Metabolic Syndrome: Findings from 20 Years of the Tehran Lipid and Glucose Study

Context: In recent decades, investigations have been focused on the definition, incidence and predictors of metabolic syndrome (MetS) in Iranians. This study aimed to review systematically investigations on MetS, conducted among the Tehran lipid and glucose study (TLGS) participants. Evidence Acquisition: Literature on MetS documented by TLGS studies published from 2000 to 2017 were searched using Pubmed and Scopus database in English language with a combination of following keywords: Metabolic syndrome, TLGS. The harmonized definition of MetS was confirmed, based on the estimated cut point of waist circumference (WC) ≥ 95 cm for both genders in Iran. The incidence rate was 550.9/10000 person/years, lower among women (433.5/10000) than men (749.2/10000). The prevalence of abdominal obesity, high triglycerides (TG), low high density lipoprotein cholesterol (HDL-C), high blood pressure (BP), and high fasting blood glucose (FBG) was 30, 46, 69, 34, and 12%, respectively. The prevalence of MetS in adolescents was 10.1% with no significant difference between boys and girls (10.3% in boys and 9.9% in girls). A strong association of WC (OR: 2.32, CI: 2.06 - 2.59) and TGs (OR: 1.95, CI: 1.65 - 2.11) with development of MetS was found. In adolescent boys, WC had the highest OR for MetS risk. WHO-defined MetS was a significant predictor of total and cardiovascular mortality both in men (HR: 1.66, CI: 1.23 - 2.24; HR:1.93, CI: 1.26 - 2.94) and women (HR: 2.01, CI: 1.39 - 2.88; HR:2.71, CI: 1.44 - 5.09). Our results indicate high incidence of MetS in Tehranian adults and adolescents; high WC also appears to be a strong predictor of MetS. All definitions of MetS predicted cardiovascular disease.