Risk factors for daytime sleepiness in a population-based sample

The study analyzed factors associated with excessive daytime sleepiness (EDS) in the middle-aged general population. The SCAPIS (Swedish CArdioPulmonary bioImage Study) cohort (n=27,976; F:M 1:1; mean age 57.5±4.3SD yrs) assessed sleep related factors (duration and subjective quality) along with anthropometric, lifestyle, socioeconomic factors as well as somatic disease and phycological distress. EDS was assessed by the Epworth Sleepiness Scale (ESS) score. Logistic regression modelling was used to identify predictors of EDS defined as ESS score >10 in the population. The population attributable fraction (PAF) for EDS risk factors was calculated to estimate the proportional reduction of EDS in the study population if exposure to these risk factors were reduced to an ideal level. Sleep duration was related to EDS with increasing ORs for decreasing hours of sleep (7h: OR 1.2, 95%CI 1.02-1.3 to ≤4h: 1.9; 1.4-2.5; reference 8h). Insomnia (1.3; 1.2-1.43), poor sleep quality (1.2; 1.04-1.4), snoring (1.5; 1.4-1.6) and nocturnal reflux (1.5; 1.21-1.8), were identified as independent risk factors for EDS. Psychological distress such as sadness/depression (1.2; 1.1-1.3), stress (some stress: 1.4; 1.1-1.7 to constant stress 5yrs: 1.7; 1.3-2.2) and perceived control (lowest quartile: 1.7; 1.6-2.0) were also identified as independent predictors of EDS. Strongest PAF´s for the risk of EDS included psychological factors and shortened sleep time. Daytime sleepiness is multifactorial showing relationship with short sleep, impaired sleep quality and psychological distress. Increasing sleep duration and improving psychological distress levels on the societal level are likely the most important measures to improve daytime sleepiness.