PHILADELPHIA — Obesity is a risk factor for many health problems, but a new Penn Medicine study published this month in the journal Sleep suggests having a larger tongue with increased levels of fat may be a sign of obstructive sleep apnea (OSA) in obese adults.
The researchers examined tongue fat in 31 obese adults who had OSA and 90 obese adults without the condition. All subjects underwent magnetic resonance imaging and the size and distribution of upper airway fat deposits in their tongue and upper airway muscles measured.
“Previous studies showed that the human tongue has a high percentage of fat, and that tongue fat and tongue weight were positively correlated with the degree of obesity,” said study senior author Richard J. Schwab, MD, professor of Medicine in Penn’s Perelman School of Medicine and member of the Center for Sleep and Circadian Neurobiology. “This is the first study that examined OSA patients and found higher fat deposits in obstructive sleep apnea patients than in those without OSA.”
The data also showed a correlation between tongue fat volume and sleep apnea severity, and with body mass index. The researchers believe that increased tongue fat may explain the pathogenic relationship between obesity and sleep apnea.
Adults with a body mass index of 30 or higher are considered obese. The latest Centers for Disease Control and Prevention survey of nationally representative data in 2011 and 2012 reported that nearly 35 percent of U.S. adults – 78.6 million people – are obese. OSA affects more than 15 million adult Americans. The number of OSA cases is rising, mirroring the increasing weight of the average individual.
Although obesity is the strongest risk factor for development of OSA, the ways that obesity confers risk for OSA are unknown. The researchers believe the increase in fat not only increases tongue size, but also decreases tongue force and hinders the tongue from properly functioning as an upper airway dilator muscle, which can lead to apneas during sleep.
Study authors note that further studies are needed to determine if weight loss decreases tongue fat, and whether improvements in sleep-disordered breathing are associated with changes in tongue fat.
Other Penn coauthors are Andrew M. Kim, Brendan T. Keenan, Nicholas Jackson, Eugenia L. Chan, Bethany Staley, Harish Poptani, Drew A. Torigian, and Allan I. Pack.
The study was supported by funding from the National Institutes of Health (R01HL089447 and P01HL094307). For more information, see the American Academy of Sleep Medicine press release.
Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System, which together form a $7.8 billion enterprise.
The Perelman School of Medicine has been ranked among the top medical schools in the United States for more than 20 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $425 million awarded in the 2018 fiscal year.
The University of Pennsylvania Health System’s patient care facilities include: the Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center—which are recognized as one of the nation’s top “Honor Roll” hospitals by U.S. News & World Report—Chester County Hospital; Lancaster General Health; Penn Medicine Princeton Health; and Pennsylvania Hospital, the nation’s first hospital, founded in 1751. Additional facilities and enterprises include Good Shepherd Penn Partners, Penn Home Care and Hospice Services, Lancaster Behavioral Health Hospital, and Princeton House Behavioral Health, among others.
Penn Medicine is powered by a talented and dedicated workforce of more than 40,000 people. The organization also has alliances with top community health systems across both Southeastern Pennsylvania and Southern New Jersey, creating more options for patients no matter where they live.
Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2018, Penn Medicine provided more than $525 million to benefit our community.