Background Characteristics of participants.

MetS-W: World Health Organization-defined metabolic syndrome. MetS-I: International Diabetes Federation-defined metabolic syndrome. MetS-A: Adult Treatment Panel III-defined metabolic syndrome. ETS: environmental tobacco smoke. VGDF: vapours, gases, dusts or fumes. SEI: socio-economic index expressed as a percentage. PM10: particulate matter 2: nitrogen dioxide.adefined as IFG and any two of central obesity, hypertension, low HDL and high triglycerides.bdefined as central obesity and any two of IFG, hypertension, low HDL and high triglycerides.cdefined as any three of IFG, central obesity, hypertension, low HDL and high triglycerides.d defined as not having a, b and c.edefined by WHO as fasting blood glucose≥6.1mmol/L and/or diagnosis of type2diabetes; and by IDF and ATP-III as fasting blood glucose≥5.6mmol/L and/or diagnosis of type2diabetes. High triglycerides defined as fasting triglycerides≥1.7mmol/L or treatment for this condition.f defined by WHO as ≤ 0.9 mmol/L (males), ≤ 1.0 mmol/L (females); and by IDF and ATP-III as gdefined by WHO as ≥140/90, or treatment of previously diagnosed hypertension; and by IDF and ATP-III as blood pressure >130/85 mm Hg or previously diagnosed hypertension.hproportion in controls according to MetS-W/ MetS-I or MetS-A criteria respectively.Background Characteristics of participants.