Metabolic syndrome (MetS) is recognized as clustering of a number of components including hypertension, hypertriglyceridemia, low serum high-density lipoprotein cholesterol (HDL-C), impaired glucose metabolism (IGM), and abdominal obesity. It has been tightly linked to thrombotic vascular events including coronary heart disease (CHD). Worldwide prevalence of MetS is on the rise. People living in Iran, a country located in the Middle-East region, have distinct behavioral, environmental and social exposures which certainly affect the prevalence and incidence of metabolic syndrome and its comorbidities.We hypothesized that these factors may affect the course of metabolic syndrome and the burden that it imposes to the community. The purposes of MetSCoM are as follows;

1. To find the incidence of T2D, microvascular complications of T2D (diabetic retinopathy, diabetic neuropathy and diabetic kidney disease), CVD, and mortality rate of subjects metabolic syndrome.
2. To find the association of baseline, mean value during follow up visits and visit to visit variability in anthropometric variables and several metabolic laboratory variables with metabolic syndrome and its complications.
3. To find the effect of behavioral variables and environmental exposures on the course of metabolic syndrome.
4. To identify the best anthropometric, laboratory, life-style and environmental predictors of CVD and mortality rate in subjects with metabolic syndrome.
5. To estimate the economic burden of metabolic syndrome and its related

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.

Inclusion Criteria:

• Obesity or central obesity, or
• Diabetes (Fasting Plasma glucose (FPG) level ≥ 7.0 mmol/l (126 mg/dL), or Plasma glucose ≥ 11.1 mmol/l (200 mg/dL) two hours after a 75 g oral glucose load as in a glucose tolerance test, or Symptoms of hyperglycemia and casual plasma glucose ≥ 11.1 mmol/l (200 mg/dL), or Glycated hemoglobin (A1C) ≥ 6.5%),
• pre-diabetes (FPG levels of 100-125 mg/dl (5.6-6.9 mmol/l), or 2-h plasma glucose (2HPP) in the 75 g oral glucose tolerance test of 140-199 mg/dl (7.8-11.0 mmol/l), or
• Hypertension (Systolic blood pressure (SBP) ≥ 130mmHgand/or diastolic blood pressure (DBP) ≥ 85mmHg or use of anti-hypertensive drugs), or
• Low HDL-c (Serum HDL-C of <40 mg/dL for men, <50 mg/dL for women,)
• Hypertriglyceridemia, (TG>150 mg/dL)

Exclusion Criteria:

• type 1 diabetes
• type 2 diabetes who required insulin therapy at baseline
• gestational diabetes
• Any malignancy, rheumatologic diseases, chronic kidney, lung or heart diseases at baseline at baseline
• known hepatitis due to infectious and auto-immune diseases

All community dwellers aged greater than 40 years who are willing to participate will be included if met any of the following eligibility criteria; (1) central obesity, or (2) obesity, or (3) T2D or prediabetes, or (4) hypertension, or (5) hypertriglyceridemia, or (6) low high density lipoprotein-cholesterol (HDL-C).