Study objectives: To examine possible relationships between excessive sleepiness (Epworth Sleepiness Scale score >10), and age, sex, ethnicity, socioeconomic deprivation, usual sleep, and self-reported symptoms of obstructive sleep apnea.
Design: Mail-out survey to a stratified random sample of 10,000 people aged 30 to 60 years, selected from the electoral roll.
Setting: Nationwide survey of adults in New Zealand (71% response rate).
Participants: The sample design aimed for equal numbers of Măori and non-Măori participants, men and women, and participants in each age decade.
Interventions: N/A.
Measurements and results: Two-page questionnaire. Măori participants had higher mean Epworth Sleepiness Scale scores than non-Măori (7.5 versus 6.0) and were more likely to have an Epworth Sleepiness Scale score of more than 10. Logistic multiple regression modeling identified the following significant independent risk factors for having an Epworth Sleepiness Scale score >10: being Măori, male, older, reporting more or less than 7.5 to 8.0 hours usual sleep, never or rarely getting enough sleep, never or rarely waking refreshed, larger neck circumference, observed apneas, and not drinking alcohol (compared with moderate alcohol consumption).
Conclusions: The relationships between an Epworth Sleepiness Scale score >10 and sleep habits and risk factors for obstructive sleep apnea are as expected. The relationships between an ESS score > 10 and being Măori, a man, older, or more socioeconomically deprived could be related to a higher prevalence of sleep disorders in these groups. However, more research is needed to understand possible differences not only in pathophysiologic processes, but also in the wider societal trends and pressures that may impact differentially on sleep and sleepiness.