ABSTRACT
In the last decade, numerous studies and articles have shown that loneliness and social isolation in late life are public health concerns and are related to frailty and other health-related factors. Loneliness is considered to be a subjective negative feeling of the discrepancy between the desired and actual level and quality of social interactions. Social isolation can be more objective and usually quantified with the number and frequency of social contacts. UCLA Loneliness Scale, the de Jong Gierveld Loneliness Scale, and a single-item measure have been commonly used to measure loneliness. Social isolation has been evaluated using various measures, including living alone, being unmarried, residing in rural area, having a small network, less-frequent contact with, or combinations of these factors.
In addition to reviewing the prevailing literature for this chapter, two series of systematic review and meta-analysis were conducted in 2022 exploring currently available evidence on how social isolation and/or loneliness are associated with physical frailty. According to these studies, the risk of being frail is approximately doubled in those who are socially isolated (pooled odds ratio = 1.88) or feeling lonely (pooled odds ratio = 2.05) compared with their counterparts. Furthermore, a higher degree of loneliness significantly predicts subsequently worsening frailty (pooled odds ratio = 1.41). Although mechanisms underlying the association between social isolation/loneliness and frailty are not known, inflammation, unhealthy lifestyles and behaviors, and health-related comorbidities have been suspected to contribute to increased risk of frailty.
