Experts Propose New Criteria for Diagnosing Obesity
Obesity is growing fastest among children and adolescents

Diagnosing obesity should extend beyond body mass index (BMI) to include measures such as waist circumference and individual physical symptoms.

So says the Commission on Clinical Obesity, comprising 58 experts from a range of medical institutions and countries in an article published in Tuesday’s The Lancet Diabetes & Endocrinology.

There has long been a debate in the medical fraternity about whether obesity is a disease itself, or a cause of disease.

The commission introduces a definition for “clinical obesity” which it classifies as a disease, but argues that its diagnosis should be far more nuanced than BMI. BMI should rather be used to screen for obesity.

It also introduces “pre-clinical obesity”, which is associated with a variable level of health risk, but no ongoing illness.

All-or-nothing

“The question of whether obesity is a disease is flawed because it presumes an implausible all-or-nothing scenario where obesity is either always a disease or never a disease,” says  commission chair Professor Francesco Rubino.

“Evidence, however, shows a more nuanced reality. Some individuals with obesity can maintain normal organs’ function and overall health, even long term, whereas others display signs and symptoms of severe illness here and now,” adds Rubino, from the School of Cardiovascular and Metabolic Medicine and Sciences a King’s College in London.

“Considering obesity only as a risk factor, and never a disease, can unfairly deny access to time-sensitive care among people who are experiencing ill health due to obesity alone,” he adds. 

“On the other hand, a blanket definition of obesity as a disease can result in overdiagnosis and unwarranted use of medications and surgical procedures, with potential harm to the individual and staggering costs for society.”

Nuanced approach

The commission defines “clinical obesity” as being associated with “symptoms of reduced organ function, or significantly reduced ability to conduct standard day-to-day activities, such as bathing, dressing, eating and continence, directly due to excess body fat”. 

The Commission sets out 18 diagnostic criteria for clinical obesity in adults and 13 specific criteria for children and  adolescents. 

These include breathlessness, obesity-induced heart failure, knee or hip pain, with joint stiffness and reduced range of motion as a direct effect of excess body fat on the joints.

Pre-clinical obesity is defined as “obesity with normal organ function”. 

“People living with pre-clinical obesity do not have ongoing illness, although they have a variable but generally increased risk of developing clinical obesity and several other non-communicable diseases (NCDs) in the future,” according to the commission

BMI limitations

Although BMI is useful for identifying individuals at increased risk of health issues, the commission stresses that BMI is “not a direct measure of fat, does not reflect its distribution around the body and does not provide information about health and illness at the individual level”.

“Relying on BMI alone to diagnose obesity is problematic as some people tend to store excess fat at the waist or in and around their organs, such as the liver, the heart or the muscles, and this is associated with a higher health risk compared to when excess fat is stored just beneath the skin in the arms, legs or in other body areas,” says commissioner Professor Robert Eckel.

“But people with excess body fat do not always have a BMI that indicates they are living with obesity, meaning their health problems can go unnoticed,” adds Eckel, who is from the University of Colorado Anschutz Medical Campus in the US.

“Additionally, some people have a high BMI and high body fat but maintain normal organ and body functions, with no signs or symptoms of ongoing illness,” 

Appropriate care

“This nuanced approach to obesity will enable evidence-based and personalised approaches to prevention, management and treatment in adults and children living with obesity, allowing them to receive more appropriate care, proportional to their needs. This will also save healthcare resources by reducing the rate of overdiagnosis and unnecessary treatment,” says Commissioner Professor Louise Baur from the University of Sydney, Australia.

Image Credits: Commons .

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