Clinical and polysomnographic determinants of snoring.

Snoring is considered one of the hallmarks of sleep-disordered breathing, but its determinants remain obscure in both obstructive sleep apnoea (apnoeic) and non-apnoeic snorers. We aimed to document positional dependency of snoring along with its association with clinical and polysomnographic variables. Seventy-seven apnoeic and 27 non-apnoeic snorers who complained for every-night loud snoring and slept in supine and lateral positions in all sleep stages during overnight polysomnography were included. Snoring (i.e. sound intensity > 40 dB) was quantified by measuring the mean and maximum sound intensity, and snoring frequency. In apnoeic and non-apnoeic snorers, mean snoring intensity and snoring frequency were higher in supine than in lateral positions irrespective of sleep stage, and were also usually higher in N3 in comparison to rapid eye movement and/or N2 sleep stage in any given position. Positional change in snoring intensity as expressed by the ratio of mean intensity in the supine to lateral positions was independently and positively correlated with body mass index, tonsils size and age in the total of patients. Snoring is more prominent in the supine position and in N3 sleep stage in apnoeic and non-apnoeic snorers. Snoring positional dependence is determined by body mass index, tonsils size and age.