A new study in Philadelphia might be of interest to 78.6 million adults in the U.S. (the population considered to be obese based on a body mass index of 30 or higher.)*

Having a larger tongue with increased levels of fat may be a sign of obstructive sleep apnea (OSA) in obese adults, suggests a new Penn Medicine study published this month in the journal Sleep.

Though OSA affects more than 15 million adult Americans, the number of OSA cases is rising, mirroring the increasing weight of the average individual.

“This is the first study that examined OSA patients and found higher fat deposits in obstructive sleep apnea patients than in those without OSA,” said Richard J. Schwab, MD, professor of Medicine in Penn’s Perelman School of Medicine and member of the Center for Sleep and Circadian Neurobiology.

“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,” according to the study’s senior author

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.

Another sleep expert weighs in and suggests the study might support evaluation of tongue size in health screenings of certain patients.

“Tongue size is one of the physical features that should be evaluated by a physician when screening obese patients to determine their risk for obstructive sleep apnea,” said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler.  “Effective identification and treatment of sleep apnea is essential to optimally manage other conditions associated with this chronic disease, including high blood pressure, heart disease, Type 2 diabetes, stroke and depression.”

* 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  are obese.