Association Between Subjective Sleep Quality and Future Risk of Falls in Older People: Results From LOHAS

Background: Inadequate sleep is correlated with morbidity and mortality among older adults. However, the longitudinal relationship between subjective sleep quality and risk of falls in the elderly population remains to be clarified. Methods: Study participants were from Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS) sites (1,071 community-dwelling people >= 65 years of age, mean: 71 years). Subjective sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI). Occurrence of falls (defined as experiencing at least one fall) during the subsequent year was ascertained by a self-reported questionnaire. Results: Mean global PSQI score was 4.3 (SD 3.2), with 28.9% of participants rating their sleep quality as poor (PSQI > 5). A total of 210 participants (19.6%) fell at least once in the year following sleep examination. Multivariable analysis revealed that participants reporting worse subjective sleep quality had significantly higher odds of experiencing falls during the 1-year follow-up period (adjusted odds ratio [AOR] = 1.50 for each three-point increase in global PSQI score; 95% confidence interval [CI] = 1.20, 1.89). Participants in the highest global PSQI score (PSQI > 5) quartile had significantly increased odds of experiencing falls compared to those in the lowest global score quartile (PSQI < 2; AOR = 2.14; 95% CI = 1.09, 4.22). This association was similarly significant in subgroup analyses for older men and women, nonusers of sleep medication, and those without a history of falls at baseline. Conclusion: Subjective poor sleep quality, as measured by the PSQI, is longitudinally associated with greater risk of experiencing falls in community-dwelling older adults.