The causal relationship between sleep disturbances and the risk of frailty: a two-sample Mendelian randomization study

Abstract

Objective: Adequate sleep is closely related to people's health. However, with increasing age, the quality of sleep worsens. At the same time, among elderly individuals, frailty is also a disturbing factor, which makes elderly individuals more vulnerable to negative factors. To explore the relationship between the two, we conducted this study. Methods: In this paper, independent genetic variations related to insomnia, sleep duration and daytime sleepiness were selected as IVs, and related genetic tools were used to search published genome-wide association studies for a two-sample Mendelian randomization (TSMR) analysis. The inverse-variance weighted (IVW) method was used as the main Mendelian randomization analysis method. Cochran's Q test was used to test heterogeneity, MR‒Egger was used to test horizontal pleiotropy, and the MR-PRESSO test was used to remove outliers. Results: According to our research, insomnia (OR = 1.10, 95% CI 1.03–1.17, P = 2.59e−97), long sleep duration (OR = 0.66, 95% CI 0.37–1.17, P = 0.02), short sleep duration (OR = 1.30, 95% CI 1.22–1.38, P = 2.23e−17) and daytime sleepiness (OR = 1.49, 95% CI 1.25–1.77, P = 0.96e−4) had a bidirectional causal relationship with frailty. Conclusions: Our research showed that there is a causal relationship between sleep disturbances and frailty. This result was obtained by a TSMR analysis, which involves the use of genetic variation as an IV to determine causal relationships between exposure and outcome. Future TSMR studies should include a larger sample for analysis.