The Relationship Of Social Isolation And Sleep In Older Adults

With the lack of social roles,the shrinking of social networks,and the decline in physical functions,older adults experience more social isolation than other age groups.Cumulative researches have shown that social isolation is an important factor threatening the physical and mental health in older adults.Particularly in the postCOVID-19 pandemic era,the problem of social isolation among older adults has become increasingly prominent,posing challenges to the physical and mental health of this group and to the global public health system.Sleep as an important indicator of physical and mental health is also threatened by social isolation.Social isolation leads to disruptions of social cues that maintain the stable sleep-wake rhythm patterns,resulting in an increasing decline in sleep quality in older adults.Correspondingly,better sleep quality also contributes to better social relationships in older adults.Previous studies have mainly examined the cross-sectional association between subjective social isolation and subjective sleep,while have rarely included objective dimension.Meanwhile,the potential mechanisms underlying the association are still lacking.Based on the above,from both subjective and objective perspectives,this study examined the relationship between social isolation and sleep and the underlying mechanisms cross-sectionally and longitudinally in the sample of clinical and community-based older adults.Study 1 recruited clinically insomnia older adults and normal older adults,and compared the differences in subjective and objective social isolation and loneliness between the two groups.The results showed that the insomnia older adults had higher levels of objective social isolation compared to the normal group,while the differences in subjective social isolation and loneliness were not significant.The results of this study suggested that the differences in social isolation between clinically insomnia and normal older adults were specific to the measure,as evidenced by the decreasing size of social networks in sleep-disordered older adults who do not subjectively perceive social isolation.Study 2 further explored the relationship between subjective and objective social isolation and subjective and objective sleep in community-dwelling older adults.The results revealed that subjective social isolation in older adults was negatively associated to subjective sleep outcomes(PSQI total scores,sleep latency,sleep duration,and daytime dysfunction),but not with objective sleep indicators.In contrast,objective social isolation was negatively associated with objective sleep indicators(number of awakenings),but not with subjective sleep.Further mediation analysis revealed that loneliness mediated the relationship between subjective social isolation and subjective sleep(PSQI total scores).Study 3 examined the longitudinal mediating role of loneliness in the reciprocal association between social isolation and sleep from the subjective perspective based on the National Social Life,Health,and Aging Project(NSHAP),a longitudinal database.The results of the cross-lagged mediation model indicated that loneliness mediated longitudinally both in the direction from social isolation to sleep and in the direction from sleep to social isolation.After controlling for age,sex,education,race,alcohol,smoking,frequency of physical activity,and use of anxiolytics,sedatives,and hypnotics,the longitudinal mediating effect of loneliness still persisted.The results suggested that the link between subjective social isolation and subjective sleep may not be direct,but indirect through emotional factors such as loneliness.Also,the results of Study 3provide evidence from the subjective perspective to support the bidirectional model between social relationships and sleep.In summary,this study explored the relationship between social isolation and sleep in older adults and the underlying psychological mechanisms from both subjective and objective perspective.The findings showed that subjective social isolation was significantly associated with subjective sleep,and objective social isolation was significantly associated with objective sleep indicators.Also,loneliness mediated the reciprocal relationship between social isolation and sleep at the subjective level.These findings emphasized the importance of subjective perceptions in older adults,and suggested that relevant groups such as family members and social workers should prevent older adults from falling into a self-reinforcing cycle of social withdrawal that leads to social isolation,loneliness,and poor sleep.Future researches should characterize the macrostructure and microstructure of sleep using polysomnography,explore the association between objective sleep indicators and social isolation at the level of sleep electroencephalography(EEG),and elucidate the neurophysiological mechanisms underlying the relationship between social isolation and sleep in older adults.