The study of 3.5 million Britons, carried out by researchers at the University of Birmingham and presented at the European Congress on Obesity in Porto, Portugal, found that even “metabolically healthy” obese people are still at a higher risk of heart disease or a stroke than those with a normal weight range.
Metabolically healthy obesity – or more colloquially ‘fat but fit’ - is defined as those who are clinically obese by having a BMI of more than 30 kg/m2 but do not have the complications that are normally associated with obesity such as high blood pressure, diabetes or poor blood sugar control.
The researchers analysed the electronic GP health records of 3.5 million Brits over 18 from 1995 to 2015. All the Brits studied were initially free from cardiovascular disease . They were divided into groups according to their BMI and whether there was a presence absence of three metabolic abnormalities (diabetes, high blood pressure and abnormal blood fats [hyperlipidemia] which were added together to create a metabolic abnormalities school. To be defined as metabolically healthy obesity, participants had to have none of the abnormalities.
The authors then compared whether the risk of developing either coronary heart disease, a stroke, heart failure or peripheral vascular disease (PVD) was different for normal weight people or people who were metabolically healthy obesity.
Compared to normal weight individuals, those who were overweight had a 50 per cent increased risk of coronary heart disease, a seven per cent increased risk of a stroke and a doubled risk of heart failure.
Metabolically healthy obese people overall had a lower risk of PVD, however further research excluding cigarette smokers, found they had an 11 per cent increased risk compared with those with normal weight.
Dr Rishi Caleyachetty, lead researcher from the institute of applied health research, college of medical and dental sciences at Birmingham, said it was the largest study of the association between metabolically health obesity and cardiovascular disease events.
“Metabolically healthy obese individuals are at higher risk of coronary heart disease, cerebrovascular disease and heart failure than normal weight metabolically healthy individuals.
“The priority of health professionals should be to promote and facilitate weight loss among obese persons, regardless of the presence or absence of metabolic abnormalities.”
He also called for a change in the term “metabolically healthy obesity”, saying it is not a harmless condition.
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