In the past 20 years, the average rate of obesity among adults in the United States has risen by approximately 30 percent, but the rate of those with the most severe forms of obesity, or those with a body mass index, or BMI, of more than 60 kg/m2, increased by 210 percent. In a recently published research letter in the medical journal The Lancet: Diabetes & Endocrinology, researchers from Pennington Biomedical analyzed national health data from 2001 through 2023, and discovered the alarming increase in the numbers of patients with the most severe forms of obesity.
"Most attention is focused on the category of general obesity, which starts with a BMI of 30 kilograms per square meter, but there is less attention paid to prevalence of obesity of 60 BMI or greater, a category associated with an increased clinical burden, impaired mobility and elevated healthcare costs," said Dr. Philip Schauer, United Companies Life Insurance Co./Mary Kay and Terrell Brown Chair and director of the Metamor Institute at Pennington Biomedical. "This study is the first to categorize the growing pervasiveness of this extreme degree of obesity, but its gravity is not to be understated, as patients in this category face far greater health risks and comorbidities."
For comparison, the average person with a BMI of 30 kg/m² is about 30 to 40 pounds overweight, while a person with a BMI of 60 kg/m² or greater is more than 200 pounds overweight. In the study "Disproportionate Increase in BMI of ≥60 kg/m² in the USA" researchers state that though obesity with a BMI of 60 or greater was presumed to be exceedingly rare, no clear understanding was available as the many previous reports counted all individuals with a BMI at or above 30 kg/m² in a single group.
While this study is also one of the first to show the growing prevalence of BMIs between 50.0 and 59.9 kg/m², the threshold of BMI at or above 60 kg/m² is associated with an even greater severity of associated diseases. People with such extreme obesity often are not mobile or must walk with assistance or use motorized carts, have many hospital visits for treating severe illnesses, and are unable to work due to disability.
Instances of BMI above 60 kg/m² have increased concurrently with the development and prescribing of GLP-1-based medications, and though these show promise in addressing obesity, their effectiveness in patients in this group is largely unknown, as randomized controlled trials for these medications include participants with an average BMI in the range of 37 to 38 kg/m².
The rise in extreme obesity cases, now estimated to be more than 850,000 people in the U.S., also raises serious concerns for the healthcare industry, as these patients often exceed the weight limit for standard medical equipment, adding complexity to biomedical imaging, anesthesia and surgeries. The weight limits of certain medical equipment result in an inability to provide typical medical care, which may be detrimental to a population at even greater risk for comorbidities, reduced responsiveness for standard weight-loss interventions and other challenges.
The research team on the study "Disproportionate Increase in BMI of ≥60 kg/m² in the USA" were co-primary authors Dr. Michael Kachmar and Dr. Vance Albaugh, along with Dr. Schauer, Dr. Shengping Yang, Dr. Florina Corpodean, Dr. Steven Heymsfield and Dr. Peter Katzmarzyk of Pennington Biomedical, and Dr. David Freedman of the Centers for Disease Control and Prevention. Research letters published in the Correspondence section include research findings and are externally peer-reviewed. Unlike Articles containing original data, research letters are shorter and the research they contain is usually preliminary, exploratory, or reporting on early findings.
"The rate of growth in cases of obesity with a BMI of 60 or greater sends an urgent message to healthcare providers and policymakers to develop the necessary resources and infrastructure to address the challenges posed by this condition," said Dr. John Kirwan, Executive Director of Pennington Biomedical. "I commend Dr. Schauer and the research team for being the first to bring the growth rate of this condition to light and giving it the attention it is due. For this and all metabolic diseases and conditions, the research faculty at Pennington Biomedical are committed to delivering solutions from cells to society, addressing the public health challenges of our time."
The Pennington Biomedical team used direct measurements of weight and height from the robust dataset provided by the National Health and Nutrition Examination Survey, or NHANES. The analysis of BMI trends in the U.S. included non-pregnant adults aged 18 and older from 2001 to 2023, with data examined in four-year intervals. As the data showed a 29.5 percent increase in all cases of obesity, classified as individuals with a BMI of 30 kg/m² or more, those classified as having normal weight, or BMIs of 18.5 to 24.9 kg/m², and those classified as being overweight, or BMIs of 25.0 to 29.9, both decreased in the time frame.
