Metabolic syndrome' in a middle-aged Finnish population.

To investigate methods for the detection of different clusterings of the insulin-resistant abnormalities consistent with the concept of the 'metabolic syndrome' in clinical practice, and to research the occurrence of these clusters in a middle-aged Finnish population. We studied a random sample of 207 middle-aged subjects in the city of Tampere, and all 1148 subjects of four middle-aged age groups in Pieksamaki town, in central Finland. Clusterings of the following eight markers of insulin resistance were recorded as the main outcome measures: 1) at least one first-degree relative with non-insulin-dependent diabetes (NIDDM); 2) obesity: body mass index (BMI) > or = 30 kg/m2; 3) central adiposity: waist-to-hip ratio (WHR) > or = 1.00 in men and > or = 0.88 in women; 4) hypertension: systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg, or receiving drug treatment for hypertension; 5) hypertriglyceridaemia > or = 1.70 mmol/l; 6) low high-density lipoprotein (HDL) cholesterol: < 1.0 mmol/l in men and < 1.20 mmol/l in women; 7) abnormal glucose metabolism according to WHO criteria and 8) hyperinsulinaemia: fasting plasma insulin > or = 13.0 mU/l. The metabolic syndrome, defined as a clustering of dyslipidaemia (hypertriglyceridaemia, low HDL cholesterol, or both) and insulin resistance (abnormal glucose tolerance, hyperinsulinaemia, or both) was present in 17% of men and in 8% of women; this sex difference was statistically significant (P< .001). The syndrome was detectable with a sensitivity of 96% and a specificity of 55% by the combined four markers of insulin resistance (NIDDM in a close relative, obesity, central adiposity and hypertension). In clinical practice, the metabolic syndrome can be detected during normal clinical examination. The occurrence of the syndrome is already high by middle age.