Metabolic and cardiovascular implications of a metabolically healthy obesity phenotype.

Metabolically healthy obesity (MHO) is a new concept in which an individual may exhibit an obese phenotype in the absence of any metabolic abnormalities. There are a number of definitions of MHO that utilize a variety of components. The findings of clinical and basic studies indicate that subjects with MHO do not exhibit an increased mortality, an increased risk of cardiovascular disease, or an increased risk of type 2 diabetes mellitus, as compared to normal-weight controls. Although these findings imply that metabolic health is a more important factor than obesity, several studies have shown that subjects with MHO have a similar risk of metabolic or cardiovascular diseases as those with metabolically unhealthy obesity. Thus, there is still debate regarding not only the implications of the MHO phenotype but its very existence. Accordingly, future studies should focus on developing a unified definition of MHO and distinguishing subjects who will be at a high risk for metabolic and cardiovascular diseases.