Abstract
OBJECTIVE: Carotid artery intima media thickness (cIMT) and adventitial diameter (AD) are subclinical atherosclerosis indicators. Metabolic syndrome (MetS) and obesity are risk factors for atherosclerosis, but their combined impact on atherosclerosis risk is unknown. This study sought to examine the effect of the co-occurrence of MetS with obesity on cIMT and AD. METHODS: The Study of Women's Health Across the Nation (SWAN) is a multi-center, multi-ethnic study. Carotid ultrasound assessments and concurrent physiologic measurements were undertaken between 2009 and 2013. This cross-sectional analysis included 1,433 women with body mass index ≥18.5 kg/m 2 and free of prevalent clinical cardiovascular disease. Multivariable linear regression models were used to relate maximum cIMT and AD (dependent variables) with obesity, MetS and their interaction. RESULTS: The average age was 60.1 years (standard deviation [SD], 2.7 y). The prevalence of obesity and MetS was 44% and 35%, respectively. Women with obesity had a 0.051 mm larger mean cIMT and women with MetS had a 0.057 mm larger cIMT versus women without the respective conditions (both P < 0.001). There was a statistically significant interaction between obesity and MetS ( P = 0.011); women with both had a model-adjusted predicted mean cIMT of 0.955 mm (95% confidence interval [CI], 0.897-1.013), higher than those with MetS alone (0.946 mm; 95% CI, 0.887-1.005), obesity alone (0.930 mm; 95% CI, 0.873-0.988), or neither condition (0.878 mm; 95% CI, 0.821-0.935). AD results were similar. CONCLUSIONS: Early detection and treatment of atherosclerotic changes may prevent significant disease. This study suggests there is a minimal impact of obesity on carotid artery thickness beyond MetS alone. All individuals with metabolic dysfunction, regardless of obesity status, should be considered at increased risk for atherosclerotic changes.