Habitual snoring in an outpatient population in Japan

In order to investigate the occurrence and history of sleep problems in Jap an, the 11-Centre Collaborative Study on Sleep Problems (COSP) project was carried out. Complaints of snoring are examined, and its prevalence, risk f actors and screening reliability are discussed. The subjects who participat ed in the study were 6445 new outpatients from a general hospital. They wer e asked to answer a sleep questionnaire that consisted of 34 items with sev en demographic items; each item was composed of four grades of frequency. I n order to offset possible seasonal variations in sleep habits, data were c ollected across four seasons. Sleep patterns, insomnia, hypersomnia, paraso mnia and circadian rhythm sleep disorders were covered. Habitual snoring wa s seen in 16.0% of males and 6.5% of females. Male predominance was noted. From these data: the relationship between habitual snoring and sleep compla ints was statistically analyzed. Habitual snorers (HS) were observed to wak e up more frequently during sleep (17.8% of males. 21.5% of females) than w ere non-habitual snorers (NHS; 6.6% of males, 9.7% of females). Mid-sleep a wakening of HS was also more frequent than it was for NHS; however, there w ere no differences in difficulty in falling asleep and early morning awaken ing. Body mass index, cigarette smoking and alcohol consumption were also c orrelated with habitual snoring.