Reduced tongue fat may be the reason that losing weight is linked to improved function among obese people with obstructive sleep apnea (OSA), new study findings indicate.
"New treatments that reduce tongue fat should be considered for patients with OSA," write Stephen H. Wang, BA, with the Albert Einstein College of Medicine in New York City, and colleagues. The findings were published online January 10 in the American Journal of Respiratory and Critical Care Medicine.
"Our group has shown that tongue fat is increased in obese patients with OSA, compared to obese patients without OSA," they write, adding that similar relationships may exist for other parts of airway anatomy that play a role in OSA risk.
Though weight loss has been tied to sleep apnea improvement, the reason for that had not been clear.
Wang is also affiliated with the Center for Sleep & Circadian Neurobiology at the University of Pennsylvania in Philadelphia, as is the study's co-lead author, Brendan Keenan, MS.
The researchers studied 67 obese patients with OSA who were undergoing intensive lifestyle modification or bariatric surgery. They were recruited from the Penn Center for Sleep Disorders, the University of Pennsylvania's Bariatric Surgery Program, or the Center for Weight and Eating Disorders.
The team used MRI and statistical analysis to measure changes before and after the weight loss interventions. They noted that several upper airway measurements changed with weight loss in addition to tongue fat, including the shape of the retropalatal airway and pterygoid volume and the lateral walls. However, other upper airway dimensions did not change.
Weight loss may affect upper airway components differently, which may be genetically determined, the authors conclude.
Reduced tongue fat should also improve muscle function, which could prevent collapse during sleep, they write.
Whatever the mechanism, the findings demonstrate that targeting tongue fat may help improve performance on the apnea-hypopnea index for people with OSA.
Different diets may have different effects on reductions in tongue fat, the authors say, though they acknowledge that has not been tested.
Wang and Keenan's team also hypothesized that cold therapies could also potentially reduce tongue fat.
"For example, cryolipolysis is a non-invasive cooling technique that lyses
adipocytes and is effective and safe for reducing abdominal and submental fat," they explain, adding that perhaps a similar technique could cut tongue fat.
Findings May Explain Why Surgery Success Is Limited
The study may also help explain why the upper airway surgery coblation has not been more effective, the authors say.
"Coblation does not discriminate between muscle and fat, but instead uses radiofrequency and water to generate a plasma that vaporizes all soft tissue types," they explain.
If just fat tissue was removed, they reason, coblation could be more effective, a theory they say warrants further study.
The study was supported by the National Institutes of Health. Coauthor David Sarwer, PhD, reports consulting relationships with BARONova, Merz, and NovoNordisk. The remaining authors have disclosed no relevant financial relationships.
Am J Resp Crit Care Med. Published online January 10, 2020. Abstract
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Cite this: Less Tongue Fat From Weight Loss May Help Sleep Apnea - Medscape - Jan 16, 2020.