A large study of 3.5 million people has found that apparently “healthy” obese people are still at higher risk of cardiovascular disease events than the general population.
The idea that some patients can be “fat but fit” is not supported by the evidence, according to researchers from Birmingham University.
“So-called metabolically healthy obesity is not a harmless condition”
They found so-called “metabolically healthy obese” patients – who have a body mass index but no metabolic complications, such as abnormal blood fats, poor blood glucose control or hypertension – are still at higher risk of heart failure or stroke than normal weight people.
Their study findings, which are yet to be published, were presented at this year’s European Congress on Obesity in Porto.
The researchers analysed a large UK database of general practice records and assembled a cohort of 3.5 million individuals aged 18 years or older and who were initially free from cardiovascular disease.
They divided the population into groups according to BMI and the presence or absence of diabetes, hypertension, and hyperlipidemia.
“The priority of health professionals should be to promote and facilitate weight”
To be classified as “metabolically healthy obese”, individuals had to have none of the three metabolic abnormalities.
The study examined whether the risk of developing four cardiovascular conditions – coronary heart disease, cerebrovascular disease, heart failure, and peripheral vascular disease – was different for normal weight people with no metabolic conditions or people with metabolically healthy obesity.
The study authors found that, compared to normal weight individuals with no metabolic abnormalities, individuals with metabolically healthy obesity had a 50% increased risk of coronary heart disease.
They also had a 7% increased risk of cerebrovascular disease and a doubled risk of heart failure, after taking into account demographics and smoking behaviour.
In addition, excluding smokers, those with metabolically healthy obesity had an 11% higher risk of developing peripheral vascular disease.
The study also showed that the risk of cardiovascular disease events in obese individuals increased with an increased number of metabolic abnormalities being present.
Compared to a normal weight person with no abnormalities, an obese person with three abnormalities had a 2.6 times increased risk of heart disease, a 58% increased risk cerebrovascular disease, a 3.8 times increased risk of heart failure, and a 2.2 times increased risk of peripheral vascular disease.
‘Healthy’ obese people still at higher risk of CVD events
Study author Dr Rishi Caleyachetty, from the Institute of Applied Health Research at the University of Birmingham, said: “This is the largest prospective 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,” he said.
“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,” said Dr Caleyachetty.
He added: “At the population-level, so-called metabolically healthy obesity is not a harmless condition and perhaps it is better not to use this term to describe an obese person, regardless of how many metabolic complications they have.”