The Effect of Age in the Association between Frailty and Poor Sleep Quality: A Population-Based Study in Community-Dwellers (The Atahualpa Project)

Purpose: To assess the effect of age in the association between poor sleep quality and frailty status. Design and Setting: Population-based, cross-sectional study conducted in Atahualpa, a rural village located in coastal Ecuador. Methods: Out of 351 Atahualpa residents aged ≥60 years, 311 (89%) were interviewed with the Pittsburgh Sleep Quality Index (PSQI) and the Edmonton Frail Scale (EFS). The independent association between PSQI and EFS scores was evaluated by the use of a generalized linear model adjusted for relevant confounders. A contour plot with Shepard interpolation was constructed to assess the effect of age in this association. Results: Mean score in the PSQI was 5 ± 2 points, with 34% individuals classified as poor sleepers. Mean score in the EFS was 5 ± 3 points, with 46% individuals classified as robust, 23% as prefrail, and 31% as frail. In the fully adjusted model, higher scores in the PSQI were significantly associated with higher scores in the EFS (β 0.23; 95% CI 0.11-0.35; P < .0001). Several clusters depicted the strong effect of age in the association between PSQI and EFS scores. Older individuals were more likely to have high scores in the EFS and the PSQI, and younger individuals had low EFS scores and were good sleepers. Clusters of younger individuals who were poor sleepers and had high EFS scores accounted for the independent association between PSQI and EFS scores. Conclusions: This study shows the strong effect of age in the association between poor sleep quality and frailty status.