Weight loss improves sleep apnoea by reducing tongue fat

Obese patients with obstructive sleep apnoea (OSA) have improved symptoms from weight loss due to a reduction in tongue fat.

In “Effect of Weight Loss on Upper Airway Anatomy and the Apnea Hypopnea Index: The Importance of Tongue Fat,” Richard J. Schwab, MD, and co-authors used MRI to measure the effect of weight loss on the pharyngeal structures surrounding the upper airway, and found that weight loss reduces tongue fat in people with OSA.

OSA causes patients to stop breathing repeatedly for short periods while sleeping. Obesity is the primary risk factor for OSA, and previous studies have demonstrated that weight loss can lead to fewer episodes of not breathing.

In a previous study, Dr. Shcwab showed that tongue fat was increased in obese patients with sleep apnoea compared to obese people without sleep apnoea. The new study was conducted to “determine if weight loss would decrease tongue fat and improve sleep apnoea”.

67 participants were included in the study, all of whom were obese and had mild to severe OSA. Over 6 months, participants lost almost 10% of their body weight on average, through diet or weight loss surgery. The Apnoea/Hypopnea Index (AHI) measures how often a patient’s breathing stops completely or partially while sleeping – overall, the participants’ AHI scores improved by 30.7%.

The results of the study revealed that reductions in tongue fat resulted in the greatest improvements in OSA. Around 30% of the improvement was attributable to the reduction in tongue fat. The more weight a patient lost, the more tongue fat was reduced, and therefore the greater the improvement in OSA.

The study also found that weight loss resulted in reduced pterygoid (one of the jaw muscles that controls chewing) and pharyngeal lateral wall [muscles on the sides of the airway] volumes. Both of these resulted in improved OSA, but not to the same extent as reduced tongue fat.

The authors believe that the results may present a new therapeutic target for OSA, and suggest that future studies could investigate whether certain low-fat diets are better than others in reducing tongue fat, and whether cold therapies used to reduce stomach fat might be applied to reducing tongue size.

“Our study is the first to show that weight loss decreases tongue fat in patients with sleep apnea, which explains an important mechanism for the improvements in sleep apnea with reductions in weight,” Dr. Schwab said. “Our findings suggest a potential unique therapeutic target for patients with obesity and sleep apnea, i.e., reductions in tongue fat.”

https://www.newswise.com/articles/weight-loss-improves-sleep-apnea-primarily-by-reducing-tongue-fat?sc=mwhr&xy=10000928