Patients who have metabolically healthy obesity but are free from other metabolic risk factors do not have an increased rate of mortality, a new study has found.

Metabolically healthy obesity is a debatable medical condition characterized by obesity which does not produce metabolic complications. The study, published in the journal Clinical Obesity, showed that unlike dyslipidemia, hypertension and diabetes -- each one of which is related to high mortality risk -- obesity alone does not pose any threat to life. "We are showing that individuals with metabolically healthy obesity are actually not at an elevated mortality rate," said lead author Jennifer Kuk, Associate Professor at the York University in Canada.

"We found that a person of normal weight with no other metabolic risk factors is just as likely to die as the person with obesity and no other risk factors," Kuk added. For the study, the research team followed 54,089 men and women from five cohort studies who were categorized as having obesity alone or clustered with a metabolic factor, or elevated glucose, blood pressure or lipids alone or clustered with obesity or another metabolic factor.

The researchers looked at how many people within each group died as compared to those within the normal weight population with no metabolic risk factors. They found that one out of 20 individuals with obesity had no other metabolic abnormalities. "This is in contrast with most of the literature and we think this is because most studies have defined metabolic healthy obesity as having up to one metabolic risk factor," said Kuk.

"This is clearly problematic, as hypertension alone increases your mortality risk and past literature would have called these patients with obesity and hypertension, 'healthy'. This is likely why most studies have reported that 'healthy' obesity is still related with higher mortality risk," Kuk noted. Earlier, a study, published in The Lancet Diabetes and Endocrinology journal, found that women with metabolically healthy obesity were at 39 per cent higher risk of cardiovascular disease.