Study objectives: To examine (1) the prevalence of home-monitored sleep-disordered breathing (SDB) and obstructive sleep apnea syndrome in a Japanese working population and (2) whether home monitoring with a type 3 portable monitor and actigraphy can produce reliable data to analyze SDB in usual lifestyles.
Methods: A cross-sectional survey using a self-administered questionnaire was conducted on a group of employees at a wholesale company in Osaka, Japan. Examinations by physicians and by sleep monitoring were also performed. Unattended home cardiorespiratory (type 3) sleep studies with actigraphy were conducted for 2 nights to diagnose SDB in 322 subjects. From the baseline questionnaires and sleep diaries, participants were assessed to follow their usual lifestyles during the study (e.g., time in bed, alcohol intake).
Results: Of 466 Japanese male employees, 396 responded to the questionnaire survey (85.0%). Results from 322 male employees aged 23 to 59 (43.8 +/- 8.4 years) were analyzed. Respiratory disturbance index (RDI), calculated from the type 3 portable monitors and actigraphy, was highly reliable with an intraclass correlation of 0.98 for interscorer reliability and with an intraclass correlation of 0.95 for night-to-night reliability. Prevalence of mild (5 < or = RDI < 15), moderate (15 < or = RDI < 30) and severe (RDI < or = 30) SDB in this population were 37.4%, 15.7%, and 6.6%, respectively. The prevalence of obstructive sleep apnea syndrome (RDI > or = 5 and Epworth Sleepiness Scale score > 10) was 17.6%.
Conclusions: The prevalence of moderate to severe SDB (RDI > or = 15) was 22.3% in this Japanese male working population aged 23 to 59, measured in participant's usual life settings. Unattended home monitoring with type 3 portable monitors and actigraphy was highly reliable and may be suitable for analyzing SDB in the usual lifestyle setting.