In the October (yes, I am behind) edition of the Journal of Clinical Sleep Medicine, there is an article about how snoring correlates with the severity of obstructive sleep apnea (OSA). Snoring occurs in 25% of women and 45% of men, and is the most common symptom of OSA. Snoring is considered a "cosmetic" issue and is not associated with other illnesses like high blood pressure, cardiovascular disease, stroke, or metabolic syndrome, the way OSA is.
This study was the first one to use an objective measurement of snoring intensity in a large (>1600) group of patients to determine the relationship between OSA and snoring loudness. They measued snoring during a sleep study with a digital sound meter. In this study, there were more males than females. Men were older, heavier, and had larger neck circumferences than women.
The results showed that men had louder snoring than women (big surprise, huh?), and this was consistent across all sleep stages, body positions, and weight. Snoring was louder among those that were heavier, had larger neck sizes, and when sleeping on the back, regardless of gender. Snoring was more common in non-dream (NREM) than dream (REM) sleep. As expected, snoring got louder as the OSA got more severe. I've told patients about this observation in my clinical practice, and now there is objective proof.