['The insulin resistance syndrome is related to arterial stiffness in diabetic subjects. Whether the insulin resistance syndrome is also related to arterial stiffness in non-diabetic subjects is less clear. We studied the association between variables of the insulin resistance syndrome in relation to arterial distensibility in healthy middle-aged non-diabetic women.', 'This study was done in 180 non-diabetic women, aged 43-55, selected from the general population. Arterial distensibility was assessed in the carotid artery. The associations were evaluated using linear regression analyses.', 'Strong associations were found between arterial distensibility and the variables of the insulin resistance syndrome: body mass index, waist-to-hip ratio, high-density-lipoprotein-cholesterol, triglycerides, glucose, insulin, apolipoprotein A1, plasminogen activator inhibitor-1-antigen and tissue-type plasminogen activator-antigen. After additional adjustment for mean arterial pressure, common carotid arterial distensibility remained associated with body mass index: beta-coefficient (95% confidence interval) per kg/m2: -0.24 (-0.42; -0.06); waist-to-hip ratio: -26.62 (-40.59; -12.65) per m/m; triglycerides: -1.42(-2.77; -0.08) per mmol/l; plasminogen activator inhibitor-1-antigen: -0.01 (-0.02; -0.00) per ng/ml and borderline significant associated with high-density-lipoprotein-cholesterol: 1.93 (-0.01; 3.87; p = 0.07) per mmol/l. Clustering of variables of the insulin resistance syndrome was strongly related to decreased arterial distensibility which remained after adjustment for mean arterial pressure. No association was found between arterial distensibility and variables that are not part of the insulin resistance syndrome: total cholesterol, LDL-cholesterol and apolipoprotein B.'] Are variables of the insulin resistance syndrome associated with reduced arterial distensibility in healthy non-diabetic middle-aged women?