Poor Sleep Quality and the Prevalence of Intrinsic Capacity Impairments Among Community-Dwelling Older Adults: A Cross-Sectional Study

Introduction: Sleep quality has been associated with cognitive, psychological, and physical outcomes in older adults; however, its relationship with intrinsic capacity (IC) as a multidimensional construct remains insufficiently understood. Objective: Our objective was to investigate the association between sleep quality and overall IC and its individual domains in community-dwelling older adults. Methods: This cross-sectional study included 477 physically independent community-dwelling adults. Sleep quality was assessed using the Brazilian Portuguese version of the Pittsburgh Sleep Quality Index. The five IC domains were assessed using the Montreal Cognitive Assessment, 15-item Geriatric Depression Scale, Short Physical Performance Battery, Snellen chart and Whispered Voice Test, and Mini Nutritional Assessment. Domain scores were combined into an overall IC score ranging from 0 to 10. Overall IC and each domain were classified as preserved or impaired. Associations were examined using Poisson regression. Results: The largest association was observed for psychological impairment (PR = 1.97; 95% CI: 1.23–3.84), followed by locomotor impairment (PR = 1.32; 95% CI: 1.02–1.77). Smaller estimates were observed for overall IC (PR = 1.16; 95% CI: 0.99–1.36) and sensory impairment (PR = 1.14; 95% CI: 0.99–1.32), with confidence intervals including the null value. Little evidence of association was found for cognitive or vitality impairment. Conclusions: Poor sleep quality was associated with a higher prevalence of psychological and locomotor impairment. However, overlapping confidence intervals and the absence of formal comparisons between outcomes preclude concluding that the associations differ across IC domains.