Association between sleep quality, sleep duration, and physical frailty among adults aged 50 years and older in India.

Background: Considering the significant growth in India's aging population, it is imperative to identify factors associated with frailty among older Indians. This study examined the association between sleep quality, sleep duration, and physical frailty among older adults in India. Moreover, we examined whether the associations between sleep quality, sleep duration, and physical frailty varied by gender.

Methods: In this secondary analysis, we used data from the 2015 wave 2 of the Study on Global Aging and Adult Health (WHO-SAGE) in India, comprising a sample of 6,512 older adults aged 50 years and above. Pre-frailty and frailty were assessed using the modified version of the frailty phenotype developed by Fried and colleagues. Sleep was assessed by self-reported quality and duration. Multinomial and multivariable logistic regression models were used to examine the associations between sleep quality, sleep duration, and physical frailty (including its components), as well as to explore the moderating effect of gender.

Results: 66.8% of older Indians were pre-frail, while 25.2% were frail. Relative to those with good sleep quality, older adults with poor sleep quality had significantly higher odds of frailty [AOR: 2.79; CI: 1.37-5.66]. Compared to those receiving the recommended age-appropriate 7-8 h of sleep, older adults sleeping ≥ 9 h reported a significantly lower likelihood of both pre-frailty [AOR: 0.73; CI: 0.57-0.93] and frailty [AOR: 0.68; CI: 0.51-0.91]. Analysis of specific components of frailty showed that older adults with long sleep had lower odds of exhaustion [AOR: 0.86; CI: 0.73-1.00] compared to those with age-appropriate sleep duration. Moreover, frailty was more pronounced in older men with poor sleep quality and short sleep duration (< 7 h/night) than in older women with similar sleep patterns. Poor sleep quality was not linked to any of the frailty components in older women; however, in older men, it was associated with exhaustion [AOR: 4.28; CI: 2.28-8.06], weak grip strength [AOR: 2.31; CI: 1.46-3.67], and low physical activity [AOR: 2.81; CI: 1.10-7.21].

Conclusion: The findings indicate potential associations between sleep quality, sleep quantity, and physical frailty among older Indians. Poor sleep quality was associated with frailty, yet long sleep duration was associated with a lower prevalence of frailty, independent of sleep quality. Moreover, the prevalence of frailty associated with poor sleep quality and shorter sleep duration was more pronounced among older Indian men than women, underscoring the need for targeted interventions to address sleep-related concerns in this demographic.