Sleep patterns and insomnia in a large population-based study of middle-aged and older adults: The Tromsø study 2015-2016.

Epidemiological studies assessing adult sleep duration have yielded inconsistent findings and there are still large variations in estimation of insomnia prevalence according to the most recent diagnostic criteria. Our objective was to describe sleep patterns in a large population of middle-aged and older adults, by employing accurate measures of both sleep duration and insomnia. Data stem from the Tromsø Study (2015-2016), an ongoing population-based study in northern Norway comprising citizens aged 40 years and older (n = 21,083, attendance = 64.7%). Sleep parameters were reported separately for weekdays and weekends and included bedtime, rise time, sleep latency and total sleep time. Insomnia was defined according to recent diagnostic criteria (International Classification of Sleep Disorders; ICSD-3). The results show that 20% (95% confidence interval,19.4-20.6) fulfilled the inclusion criteria for insomnia. The prevalence was especially high among women (25%), for whom the prevalence also increased with age. For men, the prevalence was around 15% across all age groups. In all, 42% of the women reported sleeping <7 hr (mean sleep duration of 7:07 hr), whereas the corresponding proportion among males was 52% (mean sleep duration of 6:55 hr). We conclude that the proportion of middle-aged and older adults not getting the recommended amount of sleep is worryingly high, as is also the observed prevalence of insomnia. This warrants attention as a public health problem in this population.