Background and Aims Metabolic syndrome includes a collection of risk factors that increase the risk of cardiovascular diseases and diabetes type 2. The prevalence of both conditions has been increased due to urbanization and changes in life style. The purpose of this study was to determine the prevalence of metabolic syndrome in children and its relationship with nutritional habits sleep duration and physical activity.

Methods A cross-sectional study was conducted on 338 (166 male, 172 female) children aged 10–18 years old. Waist circumference, blood pressure, blood sugar and lipid profile were measured. Metabolic syndrome defined according to IDF criteria. The pattern of nutrition, physical activity and sleep evaluated with Iranian version of international valid questionnaires.

Results Prevalence of metabolic syndrome was 11.8%. There was no significant association between sleep duration and metabolic syndrome except association between short sleep duration and high level of LDL (P<0.03). The average daily salt consumption of in metabolic syndrome patients was more than healthy children. Subjects with daily active activity more than 2 hours had lower level of LDL and metabolic syndrome prevalence (p=0.04). Metabolic syndrome was significantly lower in subjects with organized activity.

Conclusion Metabolic syndrome is highly prevalent in Iranian children. These findings suggest importance of healthy nutritional habits and organized physical activity to prevent metabolic syndrome.