Excessive daytime sleepiness among Japanese public transportation drivers engaged in shiftwork.

OBJECTIVE

To explore the actual condition of sleep disorders underlying subjective excessive daytime sleepiness (EDS) among train and bus drivers engaged in shiftwork.

METHODS

This study targeted 3109 public transportation drivers. Clinical diagnoses were made based on 147 drivers who claimed to have subjective EDS, and 285 drivers who were judged to have obstructive sleep apnea syndrome (OSAS), based on the screening process.

RESULTS

Among these subjects, the prevalence of OSAS was 3.7% and that of shiftwork disorder (SWD) was 1.5%. SWD was common among drivers who had EDS (32.7% of drivers with EDS), and their EDS severity was higher than that of OSAS drivers. The drivers with SWD were mostly young and neither obese nor hypertensive.

CONCLUSIONS

Encouraging awareness of SWD and OSAS could be necessary to prevent sleepiness-related accidents.