Abstract
BACKGROUND: This study provides the first reported estimates of the prevalence of the metabolic syndrome in a normal-weight Iranian population. SUBJECTS AND METHODS: In this population-based cross-sectional study, the study population consisted of a representative sample of 1737 males and 1707 females aged > or = 20 years with normal body mass index (BMI) (18.5-24.9 kg/m2 for both genders). The metabolic syndrome was defined according to the Adult Treatment Panel III guidelines. We present means and proportions, and multivariate odds ratios that quantify the association between metabolic syndrome and normal BMI quartiles, controlling for age, physical activity, smoking and education. RESULTS: The overall prevalence of the metabolic syndrome in normal-weight men and women were 9.9% and 11.0% (P=0.2) respectively. Men had a lower BMI than women, while their waist circumference (WC) was higher. The prevalence of high WC and low high-density lipoprotein cholesterol (HDL-C) was higher in women, while high blood pressure, high triglyceride levels and having at least one metabolic risk factor were more prevalent in men. Individuals in the highest category of normal BMI had significantly higher odds for being at risk for metabolic syndrome compared to those in the first category (OR: 5.21 for men and 2.15 for women). There was an increasing trend in odds for having all the metabolic syndrome components except for high fasting blood sugar (FBS) and high WC in men. Women showed a similar increasing trend except for high FBS across normal BMI quartiles. CONCLUSION: The prevalence of the metabolic syndrome in normal-weight Iranian adults is relatively high. Therefore, interventions for prevention of cardiovascular disease could be considered in this population.