Myocardial Infarction and Ischemic Heart Disease in Overweight and Obesity With and Without Metabolic Syndrome

Abstract

The association between overweight or obesity and ischemic heart disease is well established in observational studies,^1,2 and using a mendelian randomization approach, we recently added evidence to support that this relationship is causal.³ One plausible mechanism for this link is that overweight and obesity often are accompanied by metabolic syndrome, a cluster of cardiovascular risk factors consisting of hypertension, dyslipidemia, and hyperglycemia.⁴ Over the years, there has been considerable disagreement over the diagnostic criteria of metabolic syndrome.⁴ Despite this, it is widely accepted that metabolic syndrome per se is associated with an increased risk of ischemic cardiovascular events.^5-7 However, among overweight and obese individuals, some will, despite excessive body fat, have no or only a few other cardiovascular risk factors.^8,9 Whether coexisting metabolic syndrome is a necessary condition for the development of ischemic cardiovascular disease in overweight and obese individuals remains controversial.^10-12 Indeed, abdominal obesity is a central and previously obligatory component of metabolic syndrome that may be sufficient to identify individuals at increased risk of future cardiovascular events, even in the absence of other metabolic abnormalities. If this is the case, the overall clinical utility of metabolic syndrome in overweight and obese individuals could be questioned.