Metabolically Healthy Obesity and Carotid Intima-Media Thickness Effects of Cardiorespiratory Fitness

Objective To test the hypothesis that cardiorespiratory fitness modifies the association between metabolically healthy obesity (MHO) phenotype and carotid intima-media thickness. Patients and Methods We evaluated 3838 men (mean age, 51±6 years) who participated in the general health examination program at Samsung Medical Center, Seoul, South Korea, between January 2, 2008, and December 31, 2008. Participants were divided into 4 groups on the basis of body habitus and metabolic health status using the Asia-Pacific criteria. On the basis of Asian criteria, MHO was defined as body mass index greater than or equal to 25 kg/m² with less than 3 metabolic abnormalities. Cardiorespiratory fitness (fitness) was directly measured by using peak oxygen uptake and divided into unfit (lower tertile of fitness) and fit (middle and upper tertiles of fitness) categories on the basis of age-specific peak oxygen uptake percentiles. The prevalence of subclinical carotid atherosclerosis was defined as a mean carotid intima-media thickness greater than the 75th percentile. Results Compared with metabolically healthy normal weight (MHNW), MHO was associated with a higher prevalence of subclinical carotid atherosclerosis (odds ratio, 1.39; 95% CI, 1.12-1.72) after adjusting for potential confounding variables. Using multivariate logistic regression analysis, we found that the MHO unfit group had 2.00 times (95% CI, 1.48-2.73) and the metabolically unhealthy obesity unfit group had 1.84 times (95% CI, 1.26-2.67) higher risk of subclinical carotid atherosclerosis as compared with the MHNW fit group (reference group). However, MHO fit (OR, 1.25; 95% CI, 0.97-1.62) and metabolically unhealthy obesity fit (OR, 1.31; 95% CI, 0.90-1.92) groups had odds ratios for subclinical carotid atherosclerosis similar to those of the MHNW fit group. Conclusion Metabolically healthy obesity was associated with a higher prevalence of subclinical carotid atherosclerosis, but this association was attenuated by increasing levels of cardiorespiratory fitness.