A group of global experts is proposing a new way to define and diagnose obesity, reducing emphasis on the controversial body mass index and hoping to better identify people who need treatment for the disease caused by excess body fat.
Under recommendations released Tuesday night, obesity would no longer be defined solely by BMI, a calculation of height and weight, but would be combined with other measures, such as waist circumference, as well as evidence of health problems. related to extra kilos.
It is estimated that obesity affects more than one billion people worldwide. In the United States, about 40 percent of adults are obese, according to the U.S. Centers for Disease Control and Prevention.
“The goal of this is to get a more precise definition to target the people who really need the most help,” said Dr. David Cummings, an obesity expert at the University of Washington and one of the study's 58 authors. report published in the journal The Lancet Diabetes & Endocrinology.
The report introduces two new diagnostic categories: clinical obesity and preclinical obesity.
People with clinical obesity meet BMI and other markers of obesity and have evidence of organ, tissue, or other problems caused by excess weight. That could include heart disease, high blood pressure, liver or kidney disease, or severe chronic knee or hip pain. These people would be eligible to receive treatments, including dietary and exercise interventions and obesity medications.
People with preclinical obesity are at risk for those conditions, but do not suffer from any ongoing illness, according to the report.
BMI has long been considered an erroneous measure that can overdiagnose or underdiagnose obesity, which is currently defined as a BMI of 30 or more. But people with excess body fat don't always have a BMI above 30, the report notes. And people with high muscle mass (football players or other athletes) can have a high BMI despite having normal fat mass.
Under the new criteria, about 20 percent of people who used to be classified as obese would no longer meet the definition, a preliminary analysis suggests. And about 20% of people with serious health effects but lower BMI would now be considered clinically obese, experts said.
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“It wouldn't drastically change the percentage of people who are defined as obese, but it would better diagnose people who actually have clinically significant excess fat,” Cummings said.
The new definitions have been endorsed by more than 75 medical organizations around the world, but it is unclear how widely or quickly they could be adopted in practice. The report acknowledges that implementing the recommendations “will entail significant costs and implications for the workforce.”
A spokesperson for health insurance trade group AHIP, formerly known as America's Health Insurance Plans, said that “at this time it is too early to evaluate how plans will incorporate these criteria into coverage or other policies.”
There are practical issues to consider, said Dr. Katherine Saunders, an obesity expert at Weill Cornell Medicine and co-founder of the obesity treatment company FlyteHealth. Measuring waist circumference seems simple, but protocols differ, many doctors are not trained accurately, and standard medical tape measures are not large enough for many people with obesity.
Additionally, determining the difference between clinical and preclinical obesity would require a comprehensive health evaluation and laboratory testing, he noted.
“For a new classification system to be widely adopted, it would also have to be extremely fast, cheap and reliable,” he said.
The new definitions are likely to be confusing, said Kate Bauer, a nutrition expert at the University of Michigan School of Public Health.
“The public likes and needs simple messages. “I don’t think this differentiation is going to change anything,” he stated.
Revising the definition of obesity will take time, acknowledged Dr. Robert Kushner, an obesity expert at Northwestern Feinberg School of Medicine and co-author of the report.
“This is the first step in the process,” he said. “I think it's going to start the conversation.”
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