Objectives: To assess the prevalence of sleep-disordered breathing (SDB) and its associated symptoms in a group of commercial bus drivers in Hong Kong.
Methods: Two hundred and sixteen of 410 bus drivers from three different shifts were interviewed with the Sleep & Health Questionnaire (SHQ) and the Epworth sleepiness scale (ESS) at a Hong Kong bus depot. Seventeen subjects from each shift were then randomly selected for at-home sleep study using the Mesam IV device (Madaus Medizin-Elektronik, Freiburg, Germany).
Results: There were 207 men and nine women (mean age 42.4 +/- 7.5 years; body mass index (BMI) 25.4 +/- 4.5 kg/m2; ESS 5.3 +/- 4.2). From the SHQ it was discovered that: (i) daytime sleepiness was reported by 87 subjects (40%), (ii) snoring > or = 3 times per week was reported by 80 subjects (37%), (iii) witnessed apnoea was reported by 17 subjects (7.9%) and (iv) 29 subjects (13.4%) reported having fallen asleep during driving. Among the 51 subjects who underwent the at-home sleep study: (i) 31 subjects (61%) had respiratory disturbance index (RDI) > or = 5 per hour of sleep, (ii) 21 subjects (41%) had RDI > or = 10 per hour of sleep, (iii) 12 subjects (24%) had RDI > or = 15 per hour of sleep and (iv) 35 subjects (68.6%) snored objectively > or = 10% of the night. Ten subjects (20%) had RDI > or = 5 and sleepiness at work, while five subjects (9.8%) had RDI > or = 5 and ESS > 10. No significant differences were noted in the SHQ responses, ESS, objective snoring or RDI among the three groups. Multiple regression analysis showed that BMI and witnessed apnoea were the only positive independent predictors of RDI.
Conclusions: This study showed a high prevalence of objective snoring and SDB in a group of commercial bus drivers. Neither self-reported sleepiness nor the ESS could identify subjects with SDB.