Sleep apnea is caused when the airway is blocked because of flesh in the neck bears down on the airway. This stops air flow. UARS is upper airway resistance syndrome. This is the restriction of the sinuses and nasal passages. More likely this is indirectly related to celiac in the inflamation response earlier mentioned. Sleep apnea is most likely a condition of being overweight (much of the sleep apnea population is overweight but not all). It is possible to get in a feedback loop. Sleep apnea makes one tired. Lack of sleep results in lack of activity. Lack of activity results in weight gain. Weigh gain results in a worsening sleep apnea condition. This cycle repeats itself.
It can happen the same way with gluten. Gluten triggers a inflamation response. Airways are restricted. Sleep is interrupted. Activity is down, weight increases. Gluten and gliadin can increase appetite. Weight increases and sleeps apnea starts. Cycle repeats. Add in joint pain from inflamation and increased wieght and more activity is lost.
Treatment for both is the use of a cpap machine. It is a device that creates positive air pressure in you airways while you sleep. The positive air pressure splints open airways so breathing is not restricted.
I have the UARS variety. I am pretty lean but my nasal sinuses are restricted. 3 years of use has dramatically changed my life. Going gluten free has helped with my sinuses too, but I will always need to use the cpap device since my sinus anatomy is restricted. Gluten free obviously changed many other aspects of my life besides sleep issues.
Incidentally, an issue that I was having with my cpap lead to the discovery of celiac. I was swallowing air at night. I had a checkup with an endoscopy. Celiac was discovered.