Independent effects of obesity and cortisol in predicting cardiovascular risk factors in men and women

Objectives. Recent data suggest that higher plasma cortisol may be associat ed with hypertension and insulin resistance in otherwise healthy men, as it is in Cushing's syndrome. However, obesity in women is associated with low er plasma cortisol concentrations. This study sought to establish whether p lasma cortisol is associated with cardiovascular risk factors in women as i t is in men, and whether these relationships in either sex are confounded b y obesity. Design. A population-based cross-sectional study. Setting. The MONICA study in northern Sweden. Subjects. From a target cohort of 2500, 1921 subjects took part and 226 wer e randomly selected because they attended between 07.00 and 09.00 h after a n overnight fast. A 75 g oral glucose tolerance test was performed and bloo d sampled at baseline and 2 h after glucose. Results. Plasma cortisol was lower in relatively obese subjects: in men, th is was observed only in the 2 h sample (r = -0.23, P = 0.02) and in women o nly in the fasting sample (r = -0.26, P < 0.01). Simple regression analysis did not identify relationships between plasma cortisol and blood pressure, serum lipids, fasting insulin or glucose tolerance. However, after adjusti ng for the effect of obesity by multiple regression, higher plasma cortisol was independently associated with higher diastolic blood pressure in men ( r = 0.21, P = 0.04) but not in women, and higher fasting serum triglyceride levels in women (r = 0.28, P < 0.001) but not in men. Conclusions. Increasing obesity and plasma cortisol concentrations make ind ependent and sex-specific contributions to variations in blood pressure and aspects of the insulin resistance syndrome. Adverse cardiovascular risk is greatest in those with the combination of obesity and failure to downregul ate plasma cortisol levels.