Sleep and sickness absence: A nationally representative register-based follow-up study

Abstract

Study Objectives: We aimed to examine various sleep measures as determinants of sickness absence while considering confounders. Design: Nationally representative Health 2000 Survey linked with sickness absence data from the Finnish Social Insurance Institution. Setting: Finland. Participants: Working-aged women (n = 1,875) and men (n = 1,885). Interventions: N/A. Measurements and Results: Insomnia-related symptoms, early morning awakenings, being more tired during daytime than other people of same age, use of sleeping pills, excessive daytime sleepiness, probable sleep apnea (4 items about snoring/apnea), and reporting that sleep duration varies between different seasons were examined as determinants of sickness absence over a 7.2 year follow-up. Poisson and gamma regression models were fitted. After adjusting age, all examined sleep disturbances except excessive daytime sleepiness were associated with sickness absence among men (RRs 1.3-2.5). Among women, after adjusting for age, insomnia-related symptoms, early morning awakenings, being more tired than others, and use of sleeping pills were associated with sickness absence (RRs 1.4-1.8). After further adjustments for education, working conditions, health behaviors, and objectively measured mental and somatic health, the associations somewhat attenuated but mainly remained. The optimal sleep duration with the lowest risk of sickness absence was 7.6 hours for women and 7.8 hours for men. Although persistence of other health problems could affect the estimates, direct costs due to sickness absence could decrease by up to 28% if sleep disturbances could be fully addressed. Conclusions: This study highlights the need for prevention of sleep disturbances and promotion of optimal sleep length to prevent sickness absence.