"The Relationship between Social Support, Social Strain, and Sleep Quality among Older Adults"

Sleep quality is a critical component that impacts the well-being of older adults. According to the social-ecological model of sleep health, an individual’s sleep experience is intricately woven through influences at the individual level that are interwoven within social-level factors, all embedded within societal-level factors. This model sheds light on the idea that poor sleep quality may be attributed to social relationships, such as social support and social strain. However, longitudinal patterns of sleep quality in the older population and how they depend on social factors remain understudied. Therefore, the purpose of this dissertation work was to investigate the relationships between social factors and sleep quality in older adults over time.
This dissertation investigates the relationships between social relationships and sleep quality in older adults over time through three manuscripts. The first manuscript presents an integrative review of 21 studies on the relationship between social support and sleep quality in older adults from literature retrieved between January 2012 to November 2022. The review identified a positive association between social support and sleep quality in older adults. Furthermore, the review highlighted social support as a potential mediator between insomnia and hopelessness, as well as a possible moderator buffering the influence of rumination and negative emotions on sleep quality. However, most previous studies were cross-sectional, with limited inclusion of older adults with cognitive impairment, and the precise mechanism through which social support influences sleep quality remains incompletely elucidated.
Based on the gaps in the literature identified in first manuscript, manuscripts 2 and 3 present findings from a longitudinal study using data from The University of Michigan Health and Retirement Study (HRS) spanning from 2010 to 2018. The second manuscript identified distinct sleep quality trajectories and explored the influence of social support and social strain on sleep quality in older adults (≥ 65 years of age). The study used a group-based trajectory model to uncover three distinct sleep quality trajectories among older adults: high, moderate, and poor sleep quality. The result of multinomial logistic regression analysis revealed that higher social support was associated with a decreased likelihood of being classified in the poor sleep quality group compared to the high sleep quality group. Conversely, higher social strain scores increased the probability of membership in the poor sleep quality group. A panel data analysis using a fixed effects model was employed to investigate the relationship between sleep quality, social support, social strain, and sociodemographic factors. The results supported the role of social support in predicting sleep quality over time, but social strain was not a significant predictor.
The third manuscript examines the role of loneliness as a mediator in the relationships among social support, social strain, and sleep quality in older adults (≥ 51 years of age) and how cognitive status may moderate these associations. The study employed mediation and moderation analyses using a cross-lagged panel model. The findings revealed that loneliness mediated the impact of social support and social strain on sleep quality. The effect of social support on sleep quality via the mediator loneliness differed by the levels of cognitive status. Individuals with better cognitive function were found to experience an amplified impact of social support on sleep quality through reduced loneliness compared to those with lower cognitive function. However, the mediating effect of loneliness on the relationship between social strain and sleep quality remained independent of cognitive status.
Findings from this dissertation work underscore the importance of social support in promoting better sleep quality among older adults and highlight the complex interplay between and among social factors, loneliness, cognitive status, and sleep quality. Tailored interventions targeting social support and loneliness while considering cognitive differences are imperative for promoting a holistic approach to improving sleep quality in this aging population. Future research should focus on developing and testing the effectiveness of tailored interventions aimed at enhancing social support and reducing loneliness among older adults, with particular attention to addressing cognitive differences. Additionally, examining the long-term impact of such interventions on sleep quality and overall well-being would provide a better understanding of the complex interplay between social relationships, loneliness, cognitive status, and sleep quality. This would also offer valuable insights for developing comprehensive approaches to address sleep problems in older adults.