Metabolic syndrome is associated with reduced flow mediated dilation independent of obesity status.

Background: Data suggest that metabolic health status, incorporating components of metabolic syndrome (MetS), predicts cardiovascular disease (CVD) risk better than BMI. This study explored the association of MetS and obesity with endothelial function, a prognostic risk factor for incident CVD. Methods: Forty-four participants were phenotyped according to BMI as non-obese vs obese (30 kg/m2) and according to the International Diabetes Federation criteria of MetS: ≤2 criteria MetS (MetS-) vs ≥3 criteria MetS (MetS+); (1.)non-obese MetS- vs (2.) non-obese MetS+ and (3.) obese MetS- vs (4.) obese MetS+. Flow-mediated dilation (FMD), body composition including liver fat (MRI and spectroscopy), dietary intake, intensities of habitual physical activity and cardio-respiratory fitness were determined. Variables were analysed using a one-factor between-groups ANOVA and linear regression; mean (95% CI) are presented. Results: Individuals with MetS+ displayed lower FMD than those with MetS-. For non-obese individuals mean difference between MetS+ and MetS- was 4.1% ((1.0, 7.3); P = 0.004) and obese individuals had a mean difference between MetS+ and MetS- of 6.2% ((3.1, 9.2); P < 0.001). Although there was no association between BMI and FMD (P = 0.27), an increased number of MetS components was associated with a lower FMD (P = 0.005), and after adjustment for age and sex, 19.7% of the variance of FMD was explained by MetS, whereas only 1.1% was explained by BMI. Conclusions: In this study cohort, components of MetS, rather than obesity per se, contribute to reduced FMD, which suggests a reduced bioavailability of nitric oxide and thus increased risk of CVD