Causal Associations Between Sleep Traits and Low Grip Strength: A Bidirectional Mendelian Randomization Study

Area of Science:

• Gerontology
• Sleep Medicine
• Genetics

Background:

• Sleep disorders and low grip strength are common in the elderly, causing significant socioeconomic impact.
• Previous studies suggest an association, but a clear causal relationship is lacking.

Purpose of the Study:

• To determine the causal association between various sleep traits and low grip strength using a Mendelian randomization approach.
• Investigated sleep duration, insomnia, daytime napping, sleep-wake disorders, and chronotype.

Main Methods:

• Utilized genetic variants from UK Biobank and FinnGen genome-wide association studies (GWAS).
• Employed Mendelian randomization techniques including inverse variance weighting (IVW), weighted median (WM), and MR-Egger.
• Conducted sensitivity analyses to ensure robustness of findings.

Main Results:

• Sleep duration showed a causal negative association with low grip strength (OR = 0.618).
• Sleep-wake disorders were causally associated with increased low grip strength (OR = 1.018).
• Increased daytime napping was causally linked to higher risk of low grip strength (OR = 1.018).

Conclusions:

• Established causal relationships between sleep duration, sleep-wake disorders, and low grip strength.
• Findings support early clinical interventions to enhance elderly quality of life.