Metabolically Healthy Obesity and Coronary Artery Calcification
Do coronary artery calcium (CAC) scores differ between metabolically healthy obese and metabolically healthy normal-weight individuals?
Data from the Kangbuk Samsung Health Study, a cohort of South Korean men and women who underwent annual or biennial health examinations, were used for the present analysis. This was a cross-sectional study of 14,828 adults ages 30-59 years without known cardiovascular disease. Each participant completed a health exam, which included a computed tomography scan for coronary artery calcium (CAC) scoring. Being metabolically healthy was defined as not having any metabolic syndrome component and having a homeostasis model assessment of insulin resistance (HOMA-IR) <2.5.
The mean age and body mass index (BMI) of the 14,828 metabolically healthy participants were 39.3 years and 23.0 kg/m2 (BMI range, 14.5-39.9 kg/m2), respectively. Age, fasting glucose, systolic and diastolic blood pressure, total cholesterol, triglycerides, low-density lipoprotein cholesterol, uric acid, insulin, HOMA-IR, high-sensitivity C-reactive protein, exercise, and current alcohol use were positively associated with BMI, whereas high-density lipoprotein cholesterol and current smoking were inversely associated with BMI. Of the 14,828 subjects, 859 subjects (5.8%) had a CAC score from 1-80 and 144 subjects (1.0%) had CAC score >80. The CAC score ratio comparing metabolically healthy obese to normal-weight participants was 2.26 (95% confidence interval, 1.48-3.43) after adjustment for age, sex, smoking status, alcohol intake, exercise, and education. Further adjustment for metabolic risk factors markedly attenuated this association, which was no longer statistically significant (CAC score ratio, 1.24; 95% CI, 0.79-1.96). These associations did not differ by clinically relevant subgroups.
The investigators concluded that metabolically healthy obese adults have a higher prevalence of subclinical coronary artery atherosclerosis compared to normal-weight adults.
These data suggest that higher weight, even among those who are apparently healthy, increases the risk for atherosclerosis. Whether weight loss eliminates or reduces progression of coronary artery atherosclerosis is an important question that needs to be addressed.
Keywords: Coronary Artery Disease, Insulin, Atherosclerosis, Blood Pressure, Risk Factors, Uric Acid, Smoking, Glucose, Metabolic Syndrome X, Cholesterol, C-Reactive Protein, Body Mass Index, Obesity, Triglycerides
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