The global crisis of loneliness: a call for contextualised, mechanistic research

A decade ago, urgent calls were made to address the harms of social isolation and loneliness experienced by older adults living with a chronic illness or in a care home.1Victor CR Loneliness in care homes: a neglected area of research?.Aging Health. 2012; 8: 637-646Crossref Scopus (67) Google Scholar The urgency of this call was repeated recently by the WHO launch of a commission to address loneliness as a pressing health threat.2WHOWHO launches commission to foster social connection.https://www.who.int/news/item/15-11-2023-who-launches-commission-to-foster-social-connectionDate: November, 2023Date accessed: February 1, 2024Google Scholar Our collective struggle to effectively tackle this problem, which is paradoxically both long-standing and urgent, continues as we do not have clear guidance about which interventions are effective to combat loneliness and social isolation in a diverse population of adults who are ageing with chronic illness.3Freedman A Nicolle J Social isolation and loneliness: the new geriatric giants: approach for primary care.Can Fam Physician. 2020; 66: 176-182PubMed Google Scholar This growing field has historically been challenged by conceptual confusion in defining loneliness, isolation, and other concepts. Conceptual clarity is critical if we are to design effective interventions that tackle modifiable factors influencing the distinct (but related) problems of social isolation and loneliness experienced within diverse groups and contexts.4O'Rourke HM Collins L Sidani S Interventions to address social connectedness and loneliness for older adults: a scoping review.BMC Geriatr. 2018; 18: 214Crossref PubMed Scopus (187) Google Scholar In The Lancet Healthy Longevity, Lara Pivodic and colleagues5Pivodic L Van den Block L Pivodic F Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal study.Lancet Healthy Longev. 2024; (published online March 12.)https://doi.org/10.1016/S2666-7568(24)00011-4Google Scholar drew on Holt-Lunstad's work to clearly distinguish between structure, function, and quality components of social connection.6Holt-Lunstad J Why social relationships are important for physical health: a systems approach to understanding and modifying risk and protection.Annu Rev Psychol. 2018; 69: 437-458Crossref PubMed Scopus (367) Google Scholar They conducted a longitudinal study across 19 countries to explore (with bivariate analyses) the changes in older peoples' social connection during participants' last years of life, and evaluated (with mixed effects logistic regression) whether six social connection measures predicted end-of-life outcomes (as reported by proxy respondents). The sample of 3662 participants was derived from the multinational Survey of Health, Ageing and Retirement in Europe (SHARE), an ongoing longitudinal study of ageing that uses probability sampling within the EU. Their findings revealed that structural measures of social connection (such as social network size, contact frequency, and geographical proximity to network members) remained stable over time. In contrast, functional aspects of social networks changed, with higher levels of social support and loneliness observed over time. In the context of end of life, additional kinds of personal support are needed, which might be an explanation for the observed increases in social support. The reasons as to why loneliness increased over time, despite stable structural network characteristics and higher levels of social support, require further exploration. Although the changes in scores on the three-item UCLA Loneliness Scale were small and were only statistically significant in exploratory bivariate analyses, the proportion of individuals that reported often feeling left out, feeling isolated, or lacking companionship increased by 4% to 8%, signaling a potentially important change. More work is needed to determine what constitutes a clinically meaningful change on the three-item loneliness scale,7Hughes ME Waite LJ Hawkley LC Cacioppo JT A short scale for measuring loneliness in large surveys: results from two population-based studies.Res Aging. 2004; 26: 655-672Crossref PubMed Scopus (2480) Google Scholar and to understand the distinct mechanisms underlying the increases in loneliness at the end of life. Higher levels of loneliness at wave 6 of SHARE were predictive of more anxiety or sadness, trouble breathing, and having pain or taking pain medication in the last month of life, which raises questions about the causal relationship of social connection and end-of-life health outcomes. Is loneliness actually exacerbating negative outcomes at the end-of-life? Or, are these associations perhaps reciprocal or reinforcing one another through more complex pathways? A key strength of the study by Pivodic and colleagues5Pivodic L Van den Block L Pivodic F Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal study.Lancet Healthy Longev. 2024; (published online March 12.)https://doi.org/10.1016/S2666-7568(24)00011-4Google Scholar was the focus on an underexplored group: people within the last year of life. Yet, a limitation of this study is the exclusion or underrepresentation of groups who might be at highest risk of loneliness in the last year of life, including people living in care homes with cognitive impairment and those without a proxy respondent. People with cognitive impairment have also been excluded from most intervention studies addressing loneliness among older adults4O'Rourke HM Collins L Sidani S Interventions to address social connectedness and loneliness for older adults: a scoping review.BMC Geriatr. 2018; 18: 214Crossref PubMed Scopus (187) Google Scholar and care home residents.8Quan NG Lohman MC Resciniti NV Friedman DB A systematic review of interventions for loneliness among older adults living in long-term care facilities.Aging Ment Health. 2020; 24: 1945-1955Crossref PubMed Scopus (0) Google Scholar Such exclusions can perpetuate inequities in health care and a lack of understanding of the distinct causes and consequences of loneliness for those at highest risk, such as those who lack a surrogate decision-maker.9Chamberlain SA Duggleby W Fast J Teaster PB Estabrooks CA Incapacitated and alone: prevalence of unbefriended residents in Alberta long-term care homes.SAGE Open. 2019; 9 (2158244019885127).Crossref Scopus (5) Google Scholar We know that the aspects of social connection, such as social isolation, social support, and loneliness, are both distinct and inter-related, but what are the ways in which these aspects are related within and between diverse groups, and how might these relationships change over time? The authors call for epidemiological studies (with more time points), and qualitative and ethnographic research to understand the mechanisms underlying the observed associations between social connection and health outcomes.5Pivodic L Van den Block L Pivodic F Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal study.Lancet Healthy Longev. 2024; (published online March 12.)https://doi.org/10.1016/S2666-7568(24)00011-4Google Scholar To add to this list, multi-method and mixed-method evaluations of the effects and processes of complex interventions targeting loneliness10Skivington K Matthews L Simpson SA et al.A new framework for developing and evaluating complex interventions: update of Medical Research Council guidance.BMJ. 2021; 374n2061PubMed Google Scholar are also urgently needed to build the evidence base required to address the longstanding issue of loneliness and social isolation and to advance understanding of the proposed mechanisms by which interventions designed for diverse subgroups can (or cannot) address loneliness. Overall, future research must focus on the mechanisms by which loneliness is perpetuated and by which it can be ameliorated within diverse contexts and groups. This type of research will be most impactful if it is conceptually clear and builds on or adapts existing theories and frameworks, as illustrated by the authors in this study.5Pivodic L Van den Block L Pivodic F Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal study.Lancet Healthy Longev. 2024; (published online March 12.)https://doi.org/10.1016/S2666-7568(24)00011-4Google Scholar I report receiving a grant from Canadian Institutes of Health Research unrelated to the current work. Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal studySocial connection undergoes multifaceted changes towards older people's end of life, countering prevalent ideas of generally declining social trajectories. Loneliness in the final months of life might be a risk factor for end-of-life symptoms. Further research is needed to substantiate a causal relationship and to identify underpinning mechanisms, which could inform screening and prevention measures. Full-Text PDF Open Access