Abstract
Obesity is considered an important independent risk factor for both cardiovascular and metabolic diseases and mortality in general population. Obesity observed in a subset of obese patients who are protected from cardiometabolic risks has been described as a metabolically healthy obesity (MHO).
Different criteria have been used to categorize obesity as a metabolically healthy or risky (unhealthy). MHO was defined either according to an absence of components of metabolic syndrome or according to insulin sensitivity, usually measured by the homeostasis model of insulin resistance.
Prevalence of MHO is reported from 3.3 to 44.0% among obese individuals. It largely varies not only due to different definitions used but also according to age, gender and ethnicity.
In addition to insulin sensitivity, MHO is characterized by less expressed proinflammatory condition, gynoid body fat distribution, absence of fatty infiltration of the liver and skeletal muscle as well as by smaller adipocytes and less macrophages in adipose tissue. However, current clinical practice does not usually provide efficient and sensitive tools to identify precisely individual metabolic health.
Metabolically healthy phenotype results from interaction between genes and environment, particularly lifestyle factors. Metabolically healthy obese individuals do exist but they represent a non-homogenous group of patients, which includes both subjects comparable with metabolically healthy normal weight individuals as well as those with metabolic risks unrevealed by regular clinical examination.
Moreover, it should be kept in mind that both MHO and metabolically risky obesities are transitory conditions which could, in response to lifestyle changes, may increase or decrease the body weight and/or metabolic risks. Conclusion: Metabolically healthy obesity does exist.