Cross-Sectional Study of Obstructive Sleep Apnea Syndrome in Japanese Public Transportation Drivers: Its Prevalence and Association With Pathological Objective Daytime Sleepiness.

Objective: This study investigates obstructive sleep apnea syndrome (OSAS) prevalence among Japanese occupational drivers and factors associated with a pathological level of objective daytime sleepiness.

Methods: Portable monitoring device (PMD) screening was applied to 2389 Japanese male public transportation traffic drivers. Nocturnal polysomnography (n-PSG) and multiple sleep latency tests (MSLT) were administered to subjects with apnea-hypopnea index (AHI) at least 15 on PMD.

Results: In all, 235 subjects were diagnosed as having OSAS (9.8%). AHI on n-PSG at least 40 and Epworth Sleepiness Scale score at least 11 were extracted as factors associated with mean sleep latency on MSLT less than 5 minutes.

Conclusion: Prevalence of OSAS in male Japanese public transportation traffic drivers was 9.8% or greater. Individuals aware of excessive daytime sleepiness and with severe OSAS were inferred as exhibiting a pathological level of objective daytime sleepiness.