(HealthDay News) – Individuals who are metabolically healthy but obese have a better prognosis than metabolically abnormal, obese adults; and for adults with acute coronary syndrome (ACS), mortality follows a U-shaped pattern with increasing body mass index (BMI), according to two studies published online Sept 4 in the European Heart Journal.

Francisco B Ortega, PhD, from the Karolinska Institutet in Stockholm, and colleagues examined the phenotype of the metabolically healthy but obese in a cohort of 43,265 adults. The researchers found that metabolically healthy obese participants (46% of the obese subsample) had significantly better fitness than obese participants who were metabolically abnormal. Compared with metabolically abnormal obese adults, metabolically healthy but obese individuals had a reduced risk of all-cause mortality, non-fatal and fatal cardiovascular disease, and cancer mortality, after adjustment for fitness and other confounding variables. There were no significant differences in prognosis between metabolically healthy participants, regardless of their body fat (obese versus normal-fat participants).

Oskar Angerås, MD, from the University of Gothenburg in Sweden, and colleagues examined the association between BMI and mortality in 64,436 patients who underwent coronary angiography for ACS. The researchers found that, regardless of the angiographic findings and treatment decisions, the mortality risk was highest for underweight patients. For patients with significant coronary artery disease, the adjusted risk for mortality decreased with increasing BMI, up to about 35 kg/m², and then increased.

“Obesity may carry benefit up to a certain degree, and it should be recognized that obesity is not necessarily associated with abnormal metabolic function,” write the authors of an accompanying editorial.

Several editorial authors disclosed financial ties to the dietetics, pharmaceutical, and biomedical industries.

Abstract – Ortega
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Abstract – Angerås
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Editorial (subscription or payment may be required)