Association of central obesity with early Carotid intima-media thickening is independent of that from other risk factors

Abstract

We investigated whether anthropometric measurements or metabolic risk factors correlated more with vascular changes associated with obesity. One hundred never smoking subjects (71 women, 29 men) without vascular events, with blood pressure (BP) <140/90 mm Hg, LDL cholesterol <4 mmol/l, glucose <6.2 mmol/l participated. Anthropometric measurements (body mass index (BMI), waist/hip ratio (WHR), waist circumference (WC) and Waist/height ratio WHTR) and metabolic risk factors (glucose, insulin, lipid and uric acid levels plus BP) were assessed. Subjects underwent vascular measurements (Carotid intima-media thickness (IMT) using duplex ultrasonography, vascular stiffness assessment (Augmentation Index) by applanation tonometry and brachial artery reactivity tests). Risk factors were in the 'normal distribution'. BMI, WHR, WC, WHTR correlated significantly with triglyceride, HDL, LDL, insulin, glucose, uric acid and systolic BP levels (P<0.001). IMT correlated with WHTR, BMI, WC, Glucose (P<0.001), Homoeostasis Model Assessment (HOMA) and cholesterol levels (P<0.05). Only Age, WHTR or BMI were significant correlates of IMT in a multivariate analysis (P<0.01) including WHTR or BMI, with age, sex, systolic BP, HDLc and HOMA. Augmentation Index correlated with age (P<0.0001), WHTR and WC (P<0.0005) but with age only in a multivariate analysis. Brachial reactivity did not correlate with any anthropometric or metabolic parameters. Anthropometric cutoff points, (BMI > or =25, WC > or =102 cm men, > or =88 cm women, WHR > or =0.9 men, > or =0.8 women and WHTR > or =0.5 men and women) significantly differentiated normal from abnormal metabolic and vascular measurements. The WHTR ratio > or =0.5 was as reliable as the BMI cutoff > or =25 in determining metabolic and vascular abnormalities. BMI and WHTR were strongly associated with 89% agreement (P<0.0001). These results demonstrated that in 'healthy individuals', anthropometric parameters and metabolic risk factors correlated with each other, but anthropometric parameters were the only significant correlates of carotid IMT. A waist/height ratio > or =0.5 predicts both early vascular and metabolic changes. These data support a risk factor independent vasculotrophic effect of obesity.