The relationship between insomnia symptoms and frailty in community-dwelling older persons: a path analysis

Background: The relationship between sleep and frailty in older age is complex. Most previous studies focused on sleep duration, while insomnia, a common sleep problem in older adults, has not been adequately examined and the factors implicated in its association with frailty were under-explored.

Methods: A community-based sample of 345 prefrail and frail older adults were recruited and completed the measures on insomnia symptoms (Pittsburgh Sleep Quality Index) and frailty status (FRAIL Scale). The relationship between insomnia symptoms and frailty, with potential mediators including physical performance (Short Physical Performance Battery), depression (Patient Health Questionnaire-9), and level of physical activity (Physical Activity Scale for the Elderly), were tested in path analysis adjusting for age, gender, body mass index and sleep medications.

Results: The prevalence of sleep-onset insomnia was higher in frail participants than their prefrail counterparts (48% vs. 34%, aOR = 1.73; 95% CI 1.09, 2.76; p = 0.02), but there was no significant difference in the prevalence of sleep-maintenance insomnia (61% vs. 54%). The association between sleep-onset insomnia and frailty was explained by reduced physical performance (standardized coefficient = 0.11; 95% BCa CI [0.002, 0.233]), but not depression and level of physical activity. Sleep-maintenance insomnia was not associated with frailty.

Conclusions: Insomnia symptoms are prevalent in frail and prefrail older adults. Sleep-onset insomnia is associated with poorer physical performance, which is further linked to a higher risk for frailty in older persons. The findings highlight the importance of timely assessing and managing insomnia among older adults at risk of frailty.