Sleep apnea is highly correlated to being obese. Being obese is a top comorbidity seen in patients with bad Covid outcomes. I guess researching obvious correlations is how one makes money as a researcher.
You guess? Perhaps you should apply for a research grant to look into it...
Another correlation with sleep apnea is a-fib. This heart condition is also a comorbidty with covid. After years of living with a-fib they finally discovered that I had sleep apnea. (very severe) They found this when I went to the ER with respiratory failure. (%O2 down to 75%.)
I have been progressing back to some form of health since then using O2 at night and a ventilator. But all these symptoms are correlated and yes, I am also over weight. The hospital tested me for covid but I was negative.
My main point is that one of my doctors could have asked for a sleep study ten years earlier. This is something I would recommend to anyone who has to get up several times each night supposedly to pee. After getting the ventilator (sort of an advanced CPAP device) I only get up once per night.