A biphasic observational study will be conducted on participants with any component of metabolic syndrome in Tehran, Iran. Phase one of the study is a cross-sectional study, while the second phase is a prospective cohort. In phase one of study, the prevalence of any metabolic disorder will be estimated in the study population and the association of biochemical variables, behavioral and environmental variables with each metabolic disorder will be investigated. Afterwards, through the phase two, those with any component of metabolic syndrome will be followed to record the incidence of diabetes, vascular complications of diabetes, non-alcoholic fatty liver disease, (NAFLD), cancers, mortality rate and finally estimation of economic burden of metabolic syndrome and its components in study population. Participants will be recruited from four health surveillance centers located at East, West, North and South of Tehran, the capital city of Iran. The latitude of Tehran is 35°41' North, and 51°25' East. Participants will be followed for at least 10 years and we plan to extend this time if possible. Anthropometric, biochemical, behavioral and meteorological measurements will done on scheduled timeline.