An international commission of medical experts proposed a major overhaul of how obesity is diagnosed, moving beyond the traditional reliance on Body Mass Index (BMI). The commission's recommendations, published in the journal The Lancet Diabetes & Endocrinology, advocate for a transformative shift that incorporates additional measurements to provide a more accurate assessment of obesity.
"The reality is more nuanced," said Professor Francesco Rubino, chair of the Commission on Clinical Obesity and a professor at King's College London, according to Tagesschau. He explained that considering obesity only as a risk factor can unjustly deny access to timely medical care among people who are experiencing ill health due to obesity alone.
The commission introduces two new diagnostic categories: clinical obesity and preclinical obesity. Clinical obesity is defined as a chronic, systemic illness characterized by alterations in the function of tissues, organs, or the individual due to excess adiposity, which can lead to severe end-organ damage and life-threatening complications. Preclinical obesity involves excess adiposity with preserved function of other tissues and organs, presenting an increased risk of developing clinical obesity and other non-communicable diseases.
"Relying on BMI alone to diagnose obesity is problematic," said Professor Robert Eckel from the University of Colorado Anschutz Medical Campus. "People with excess body fat do not always have a BMI that indicates they are living with obesity."
BMI, a diagnostic tool used for the past 50 years to estimate a person's body fat, has been criticized for not reflecting fat distribution around the body and not providing information about health and illness at the individual level. According to CBC News, the commission states that using BMI to determine who is overweight or obese is not reliable and can result in misdiagnosis.
The commission outlines 18 diagnostic criteria for clinical obesity in adults, including serious indicators related to the effects of adiposity on health, such as sleep apnea and liver disease. For children and adolescents, there are 13 diagnostic criteria. "This nuanced approach to obesity will enable evidence-based and personalized approaches to prevention, management, and treatment in adults and children living with obesity, allowing them to receive more appropriate care, proportional to their needs," said Professor Louise Baur, a Commissioner from the University of Sydney, according to BBC News.
The recommendations have been endorsed by over 75 medical organizations globally, including the Royal College of Physicians, which stated that distinguishing between preclinical and clinical obesity would be "a vital step forward" and highlighted the need to identify and intervene early while providing the right care to patients whose health was already severely affected.
The commission emphasizes the importance of combining BMI with at least one body size measurement, such as waist circumference, waist-to-hip ratio, or waist-to-height ratio, or using at least two body size measurements regardless of BMI. This approach aims to address the limitations of BMI and ensure individuals receive necessary care.
"What we're proposing is to say that it's not only a health risk; for some, it is actually an illness and that needs to be diagnosed," explained Professor Rubino, according to BBC News. He added that redefining obesity was sensible to understand the level of risk in a large population, instead of the current "blurry picture of obesity."
The new definitions move away from BMI cutoffs based mainly on white, European males. "It's very important that we move away from thinking just about weight and height and focus on health," said Dr. Katherine Morrison, one of the authors of the global commission and a pediatric endocrinologist and professor at McMaster University in Hamilton, according to CBC News.
Experts acknowledge that BMI can misclassify individuals, including athletes with high muscle mass, as overweight or obese. "Some individuals with obesity can maintain normal organ function and overall health, even long term, whereas others display signs and symptoms of severe illness here and now," said Professor Rubino.
The commission's reframing of obesity aims to improve weight management practices and help patients receive more appropriate advice and care from their doctors. "Obesity should be more than a number. It should also have health consequences," said Dr. Angela Fitch, former president of the Obesity Medicine Association, according to USA Today.
Some experts expressed concerns about the practical utility of the new definitions. Independent experts consider the division into two categories partly helpful but have concerns about its practical application. There are also concerns that pressure on health budgets could mean less money for those in the preclinical obesity category.
The commission hopes that the new diagnostic criteria will lead to better healthcare resource allocation and enable fair, medically sensible prioritization of available treatment options. "The Commission's new diagnostic criteria fill a gap in the notion of obesity diagnoses as they enable clinicians to differentiate between health and illness at the individual level," said Dr. Gauden Galea, a Commissioner from the World Health Organization Regional Office for Europe.
"Studies show that the way obesity is usually talked about adds to weight stigma, making it harder to prevent, manage and treat," said Joe Nadglowski, a patient advocate and Commissioner from the Obesity Action Coalition.
The commission's report highlights that as of March 2020, nearly 42% of US adults had obesity, with the report estimating that more than a billion people are living with obesity worldwide, according to USA Today. The new approach aims to ensure that all people living with obesity receive appropriate health advice and evidence-based care when needed.
"This will also save healthcare resources by reducing the rate of overdiagnosis and unnecessary treatment," said Professor Baur.
This article was written in collaboration with generative AI company Alchemiq
