Prevalence of the metabolic syndrome in drug-treated hypertensive patientsand control subjects

Objectives. To determine the prevalence of the metabolic abnormalities asso ciated with hypertension and to define the predictors of the metabolic synd rome by different definitions in random population-based samples. Design. A cross-sectional epidemiological study of hypertensive patients an d controls. Setting. The participating study subjects visited the research laboratory o f the Department of Internal Medicine, University of Oulu, Oulu, Finland. Subjects, Six hundred treated male and female hypertensives aged 40-59 year s and 600 age- and sex-matched controls were randomly selected by age strat ification from population registers. Main outcome measures. A wide range of laboratory analyses were conducted. After fasting blood had been drawn, the subjects were given a 75 g glucose load except previously known insulin-treated diabetics. Both 1 h and 2 h gl ucose and insulin concentrations were determined. During the same visit, a standardized health questionnaire covering the past medical history, curren t and former medication use, physical activity, smoking habits, alcohol con sumption and family history was completed. Tell different definitions of th e metabolic syndrome were applied to achieve a wide perspective of the prev alence of the different combinations. Results. The prevalence of the metabolic syndrome in different samples vari ed depending on the definition from 0.8 to 35.3%, being lowest in the contr ol men and women and highest in the hypertensive men. Three-quarters of a r andom, middle-aged, urban population show at least one cardiovascular risk factor and 91.3% of all the hypertensive subjects show at least one cardiov ascular risk factor in addition to hypertension itself. The independent pre dictors of the metabolic syndrome were waist circumference, uric acid, tota l cholesterol and gamma-glutamyl transpeptidase in logistic analysis after adjustment for age, measure of obesity and gender. Conclusions. This cross-sectional, epidemiological study shows that the mag nitude of the prevalence rates of the metabolic syndrome is at the same lev el in various populations, being less than one-third in population-based sa mples in spite of the different definitions. The cluster of several cardiov ascular risk factors, especially in the hypertensives, leads to an increase d relative risk of cardiovascular diseases.