Insomnia with objective short sleep duration, objective long sleep duration, and mortality in older persons

To investigate the association of sleep phenotypes, including insomnia with objective short sleep duration (ISSD) and objective long sleep duration (LS), with mortality in older persons.

In 2844 men (average age 76.4±5.5; follow-up=12.1 years) and 2967 women (average age 83.5±3.7; follow-up=5.7 years), Cox proportional hazards models examined the association of ISSD (insomnia [difficulty initiating or maintaining sleep and/or sleep medication use ≥3/week] and concurrent actigraphy-estimated sleep duration <6 hours) and LS (actigraphy-estimated sleep duration >8 hours) with mortality. Other phenotypes (insomnia with normal sleep duration [INSD; insomnia and sleep duration 6 to 8hours]; asymptomatic short sleep [AS; no insomnia and sleep duration <6 hours]) were also examined. Participants with normal sleep (NS; no insomnia and sleep duration 6 to 8hours) served as the reference. Models were adjusted for demographics and comorbidities.

In demographic-adjusted models and across cohorts, ISSD was associated with an increased hazard of mortality compared with NS (HR 1.25 [1.09, 1.43] for men; 1.38 [1.12, 1.70] for women). This association was not significant in either cohort after adjusting for comorbidity. In unadjusted models, LS was associated with increased mortality in men and women when compared with NS. In women only, LS was associated with higher mortality after adjustment for demographics and comorbidity compared with NS (HR 1.31 [1.08, 1.60]). Persons with INSD or AS did not have increased mortality risk compared with NS.

ISSD and LS are at-risk phenotypes in older persons. Associations with mortality may be mediated by chronic diseases. Future work should examine whether sleep improvements decrease mortality in older persons.