A 10-year trend of insomnia prevalence in the adult Norwegian population

Abstract

Objective: We aimed to investigate the 10-year trend in the prevalence of insomnia symptoms, insomnia cases, and use of hypnotic agents in the adult Norwegian population.

Methods: Data from two representative surveys assessing identical insomnia symptoms in the adult population of Norway, one conducted in 1999-2000 (N=2001) and one conducted in 2009-2010 (N=2000), were compared.

Results: Controlling for basic demographic variables, significant increases were found over the 10-year study period in the prevalence of sleep-onset insomnia from 13.1% to 15.2%, dissatisfaction with sleep from 8.2% to 13.6%, daytime impairment from 14.8% to 18.8%, Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) insomnia cases from 11.9% to 15.5%, and hypnotic agent use from 6.9% to 11.1%. No secular trend was found for maintenance insomnia or for early morning awakening insomnia. Across the two surveys, women reported a higher prevalence of insomnia than men. Age was positively associated with the prevalence of nocturnal sleep problems and use of hypnotic agents but was inversely associated with daytime impairment. Individuals with low socioeconomic status (SES) reported a higher prevalence of several insomnia symptoms.

Conclusions: Insomnia seems to be on the rise in the general adult population, which gives reason for concern. Prevention of insomnia and cost-effective interventions should receive higher priority in the future.

Keywords: Epidemiology; Insomnia; Prevalence; Secular; Sleep; Trend.