Despite the fact that obesity and its detrimental effects have reached staggering proportions in recent years, there are those in the medical field that still have doubts on the condition's impact on overall mortality. Among the notions fueling such reservation is the concept of "metabolically healthy obesity." Defined as being in an obese state (BMI>25 kg/m2) without demonstrable obesity-related metabolic abnormalities such as dyslipidemia or impaired glucose tolerance, "metabolically healthy obesity" are not believed to be in need of preventative therapies. Successfully challenging this controversial conceit, a study published April 30 in the Journal of the American College of Cardiology, compared the coronary artery calcium (CAC) scores of metabolically healthy obese and metabolically healthy normal weight individuals to assess their risk of cardiovascular disease, and found that an obese, yet "metabolically healthy" state was associated with a greater prevalence of subclinical coronary atherosclerosis and cannot be considered a benign condition.

Defining one's metabolic health by the absence of fasting blood glucose ≥100 mg/dL (or use of glucose-lowering agents), blood pressure ≥130/85 mmHg (or use of blood pressure-lowering agents), triglycerides ≥150 mg/dL (or use of lipid-lowering therapies), high-density lipoprotein-cholesterol <40 mg/dL in men (or <50 mg/dL in women), and a homeostasis model of insulin resistance ≥2.5, the investigation sampled 14,828 metabolically Korean adults aged 30 to 59 years who had no known cardiovascular disease. The population was stratified into one of four categories: underweight (BMI <18.5 kg/m2), normal weight (BMI 18.5-22.9 kg/m2), overweight (BMI 23.0-24.9 kg/m2), and obese (BMI ≥25 kg/m2). Analyzing the CAC scores, the data showed that "metabolically healthy" obese group had a significantly greater prevalence of coronary atherosclerosis compared with their metabolically healthy, normal weight counterparts. Following additional adjustments for metabolic risks factors and LDL-C level however, it was revealed that this prevalence of subclinical coronary atherosclerosis in the "metabolically healthy" obese group no longer remained statically significant.

"Obese individuals who are considered 'healthy' because they don't currently have heart disease risk factors, should not be assumed healthy by their doctors," said Yoosoo Chang, MD, lead author of the study and professor at Kangbuk Samsung Hospital Total Healthcare Center for Cohort Studies in Seoul, Korea. "Our research shows that the presence of obesity is enough to increase a person's risk of future heart disease and that the disease may already be starting to form in their body. It's important that these people learn this while they still have time to change their diet and exercise habits to prevent a future cardiovascular event."

In a related editorial comment, Rishi Puri, MB, BS, Atherosclerosis Imaging Core Laboratory, writes that the findings seriously help dispel the idea that there is some level of obesity that is actually healthy, and "casts serious doubt on the concept of obese individuals maintaining a benign prognosis... Obesity adversely affects almost all physiological homeostatic mechanisms, and its presence associates with both cardiac and many non-cardiometabolic disorders including malignancy, infection, infertility, joint disease, depression and cognitive decline. Our society faces a monumental challenge to successfully tackle obesity and its complications. By labeling a subset of obese individuals as 'metabolically healthy' would undermine the ultimate task that physicians and health organizations face, to curb the current obesity epidemic and prevent the next generation of individuals from becoming obese. Failure to promote weight loss strategies to all obese individuals, and to only offer treatment to obese patients with overt metabolic derangements would seem futile and short-sighted."

Keywords: Depression, Coronary Artery Disease, Republic of Korea, Cognition, Atherosclerosis, Overweight, Risk Factors, Blood Pressure, Insulin Resistance, Calcium, Prevalence, Glucose Intolerance, Prognosis, Dyslipidemias, Body Mass Index, Blood Glucose, Obesity, Diet, Triglycerides, Habits