Abstract
Introduction
Frailty, a multidimensional construct of decreased reserve is an important predictor of functional independence and quality of life in older adults. There is a growing body of evidence highlighting reduced sleep efficiency and sleep duration predicts frailty in older adults. However, the sex differences in these relationships have been understudied.
Methods
253 participants (163) ranging in age from 50-92 years (mean= 67.59 years, S.D.= 9.22 years), underwent frailty assessment and completed the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Statistical moderation was assessed using nonparametric bootstrapping. All models statistically controlled for age, education and depression status.
Results
Higher scores on the PSQI predicted higher levels of fatigue (β=1.87, 95% CI= 0.48-3.27) and higher grip strength with the left hand (β= 0.81, 95% CI= 0.85-1.53). These relationships were significantly moderated by sex (β=-0.77, p=0.05 & β=-0.52, p=0.01). Specifically, high scores on the PSQI predicted more fatigue stronger grip strength in men (β=1.11, 95% CI=0.41-1.81) and weaker grip strength in women (β=-0.25, 95% CI=-0.51--0.02). There was no association between scores on the ESS and any of the frailty measures.
Conclusion
The relationships between PSQI scores and measures of fatigue and grip strength were statistically moderated by sex. These differences are not explained by sex differences in overall sleep quality or baseline frailty. This is consistent with the literature emphasizing sex differences in the effects of risk/lifestyle factors. It is possible that the relationship between sleep quality and frailty is altered by additional hormonal factors and warrant further investigation.
Support (if any)
This research was supported by the Evelyn F. McKnight Brain Research Foundation
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