in three new opinion papers.
The three statements were published on July 22, 2024, in Annals of Internal Medicine. In one, the authors expressed caution about the recent movement away from using BMI alone to define obesity, noting that the measure remains a useful population-level and clinical tool for addressing adiposity, particularly within racial and ethnic groups. But the authors of a second paper pointed out that the use of lower BMI cutoffs to define obesity in Asian populations, in place since 2004, is inadequate in part because it doesn’t account for heterogeneity among different Asian groups.
And in the third paper, an editorial, an Annals editor cautioned that the recent framing of obesity exclusively as a “disease” rather than a “broader, more inclusive construct” may inadvertently reinforce the bias it was meant to combat.
Asked to comment on the issues raised in the papers, Professor Gijs Goossens of Maastricht University Medical Center, Maastricht, the Netherlands, said, “It is important to emphasize that the management and treatment of obesity have wider objectives than weight loss alone and include the prevention, resolution, or improvement of obesity-related complications; achieving better quality of life and mental well-being; and improvement of physical and social functioning.”
Added Dr. Goossens, who was an author of a recent European Association for the Study of Obesity (EASO) framework calling for moving beyond BMI in defining obesity, “Personalized therapeutic goals should be set at the beginning of the treatment, according to the stage of obesity, taking into account available therapeutic options, possible side effects or risks, and patient preferences. The drivers of obesity and possible barriers to treatment should also be discussed with the patient.” Dr. Goossens emphasized that he was providing his personal views and not speaking for the EASO or his coauthors.
BMI: ‘Not a Perfect Measure of Adiposity but Remains Useful’
In their “Ideas and Opinions” paper, Adolfo G. Cuevas, PhD, of New York University School of Global Public Health, New York City, and Walter C. Willett, MD, DrPH, of Harvard T.H. Chan School of Public Health, Boston, argued that “BMI, although not a perfect measure of adiposity, remains a useful population-level and clinical tool for addressing adiposity, including within groups defined by race and ethnicity.”
They added that despite the criticism that BMI doesn’t distinguish between fat and lean body mass, the measure still strongly correlates with fat mass as well as cardiovascular risk and mortality, and it does so similarly across racial and ethnic groups.
Clinically, Dr. Cuevas and Dr. Willett pointed out that BMI correlates fat mass as assessed with the gold standard measure dual x-ray absorptiometry but is far simpler and less expensive. Measuring waist circumference can provide additional information about visceral fat and disease risk but is “more difficult to standardize and suffers from the same limitations as BMI when cut points are used.”
They suggest the addition of change in weight since early adulthood and over time as a “simple and sensitive variable” for assessing adiposity.
Luca Busetto, MD, associate professor of medicine at the University of Padua, Italy, and the first author of the EASO framework, said, “The paper from Cuevas and Willett sounds like a strong defense of BMI, and I can substantially agree with this defense ... We remain anchored on BMI, but we tried to move beyond it adding an estimate of high risk abdominal fat — waist to height ratio — and coupling the anthropometric assessment with a complete clinical evaluation and staging.”
Dr. Goossens said, “I agree with the authors that despite the limitations of BMI as a measure of body fatness, it remains a useful clinical screening tool. Yet the diagnosis of obesity should not be based solely on BMI” due to the stronger association of abdominal fat with cardiometabolic complications.
That link, he noted, “also applies to individuals with a BMI level below the current cutoff values for obesity, who may already have medical, functional, or psychological impairments. We should be aware of the risk of undertreatment in this particular group of patients.”