Insomnia Symptoms, Sleep Duration and Risk of Falls in Older Adult Women: Findings from the Study of Women’s Health Across the Nation

Background As the leading cause of injury and injury-related death for older adults in the United States, falls can be consequential for function and mortality but are preventable. Sleep may be a modifiable risk factor for falls. Methods Data from 1,795 female participants of the multi-ethnic and community-based cohort Study of Women’s Health Across the Nation (SWAN) were analyzed to examine whether frequent insomnia symptoms and shorter sleep duration are associated with an increased risk of falls or a greater number of falls. Sleep variables were measured at Visit 12 (2010-2011, analytic baseline). Insomnia symptoms were assessed through self-reported frequency of restless sleep, trouble falling asleep, and waking early and being unable to fall asleep again. Sleep duration was self-reported hours of sleep, dichotomized as fewer than <6 hours/night and ≥6 hours/night. At Visit 15 (2015-2016, analytic follow-up), participants reported the number of falls in the year prior. Log-binomial and multinomial logistic regression models were adjusted for demographic and socioeconomic factors and health conditions. Results Women who reported frequent (5+ times/week) trouble falling asleep and frequent waking in the middle of the night at baseline had a 30% increased risk (aRR = 1.30, 95% CI = 1.04, 1.62) and 24% increased risk (aRR = 1.24, 95% CI = 1.03, 1.49), respectively, of having fallen in the year prior at follow-up. Frequent trouble falling asleep and short sleep duration (<6 hours) were both associated with higher odds of falling three or more times vs. once or never prior to follow-up (aOR = 2.42, 95% CI = 1.26, 4.63; aOR = 1.77, 95% CI = 1.08, 2.93), respectively. Conclusions Multiple indicators of poor sleep, including trouble falling asleep, frequent waking, and short sleep duration, were associated with an increased risk of falling and odds of higher fall burden in older adult women. Promoting adequate, high-quality sleep may be an essential component in fall prevention.