Social Asymmetry and Risk of Morbidity and Mortality

Pei Qin; Eileen K Graham; Anthony D Ong; Andrew Steptoe

doi:10.1001/jamanetworkopen.2025.58214

. 2026 Feb 11;9(2):e2558214. doi: 10.1001/jamanetworkopen.2025.58214

Social Asymmetry and Risk of Morbidity and Mortality

Pei Qin ^1,^✉, Eileen K Graham ², Anthony D Ong ³, Andrew Steptoe ¹

PMCID: PMC12895283 PMID: 41671000

This cohort study evaluates the associations between social asymmetry and risk of incident morbidity and mortality in a national population cohort.

Key Points

Question

Is social asymmetry, referring to the discrepancy between subjective loneliness and objective social connections, associated with incident morbidity and mortality?

Findings

In this cohort study of 7845 participants with 13.6 years of follow up, higher social asymmetry was associated with increased risk of incident morbidity and mortality. Social vulnerability was associated with an increased risk of all-cause mortality, cardiovascular disease, heart failure, and chronic obstructive pulmonary disease when compared with social resilience.

Meaning

These findings suggest the importance of evaluating the discrepancy between loneliness and social isolation in studies of health outcomes and leveraging this novel measurement in future interventions.

Abstract

Importance

Social asymmetry refers to the discrepancy between subjective loneliness and objective social connections. Although both loneliness and isolation have been linked with risk of premature mortality and morbidity, the association between the 2 is poorly understood.

Objective

To explore the associations between social asymmetry and risk of incident morbidity and mortality in a national population cohort.

Design, Setting, and Participants

Prospective cohort study using data from wave 4 (2008-2009) of the English Longitudinal Study of Aging (ELSA) as baseline. Participants were aged 50 years and older living in England. Data were analyzed from April to August 2025.

Exposures

Social asymmetry was quantified as the residual score from regressing scaled loneliness on scaled social isolation.

Main Outcomes and Measures

Incident cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD), dementia, and all-cause mortality, through data linkage to hospital episode statistics and mortality registry data up to 2024.

Results

Of 7845 participants (mean [SD] age at baseline, 65.5 [9.5] years; 4283 [54.6%] women; 7694 [98.1%] White and 151 [1.9%] other race or ethnicity) with a mean (SD) follow-up period of 13.6 (4.2) years, 2775 deaths and 2415 CVD, 989 COPD, and 710 dementia cases were recorded. Higher social asymmetry (higher loneliness than estimated by isolation) was associated with increased risk of CVD (hazard ratio [HR], 1.06; 95% CI, 1.02-1.10) and all-cause mortality (HR, 1.04; 95% CI, 1.01-1.06). Compared with those in the socially resilient group, those in the socially vulnerable group had a higher risk of all-cause mortality (HR, 1.13; 95% CI, 1.04-1.22), CVD (HR, 1.16; 95% CI, 1.04-1.30), and COPD (HR, 1.21; 95% CI, 1.04-1.42). Compared with the concordant low lonely group (low loneliness, low isolation), participants in the concordant high lonely group (high loneliness, high isolation) had an increased risk for all health outcomes investigated, while those in the discordant susceptible category (high loneliness, low isolation) had an increased risk for CVD and mortality; the discordant robust group (low loneliness, high isolation) had no association for any outcomes except for dementia.

Conclusions and Relevance

In this cohort study, higher social asymmetry was associated with increased risk of incident morbidity and mortality, emphasizing the importance of evaluating both loneliness and isolation in studies of health outcomes. Future interventions could leverage this novel measurement to identify high-risk groups to target.

Introduction

Social isolation and loneliness have been studied extensively over several decades and are growing public health concerns among older people because of their negative impact on both mental and physical health outcomes.^1,2 Estimates of the prevalence of these problems vary with methods of measurement, but recent global estimates for social isolation and loneliness in older adults were 25%³ and 13%,⁴ respectively. The growing burden of aging and high prevalence of social isolation and loneliness emphasize the importance of a better understanding of the interrelationships between the 2 concepts in the context of health.^5,6

Social isolation is an objective feature of the social environment characterized by limited social contact and participation, whereas loneliness is a subjective experience of feeling alone or disconnected from others.⁷ Previous studies have shown there is a discrepancy between loneliness and isolation.^6,8 The discrepancy has been referred to as social asymmetry by McHugh et al,⁹ who proposed a clinically meaningful metric derived by considering the discrepancy between an individual’s subjective feelings of loneliness and objective measures of their social connectedness. The study found a mismatch between loneliness and isolation was associated with impaired cognitive performance.⁹ Ong et al¹⁰ proposed a revisualized score method to measure social asymmetry and found an association between greater social asymmetry and poorer physical health,¹¹ suggesting social asymmetry may also help distinguish between vulnerable and resilient individuals in terms of health risks, even at similar levels of social isolation.^11,12 This approach may therefore provide useful additional information on how social vulnerability and resilience might be linked with health.

Cardiovascular diseases (CVD), chronic obstructive pulmonary disease (COPD), and dementia are the leading causes of death globally.¹³ Loneliness and social isolation have been separately shown to increase risk of CVD,¹⁴ mortality,¹⁵ COPD,¹⁶ and dementia.¹⁷ A few studies have also investigated the combination of loneliness and social isolation with mortality,¹⁸ CVD,¹⁹ and dementia,²⁰ and findings have been inconsistent. To our knowledge, only 1 study²¹ has explored social asymmetry and mortality, and it reported a mixed set of findings depending on the specific outcome. The follow-up period was limited to 7 years. It therefore remains unclear whether social asymmetry is related to all-cause mortality and to incidence of CVD, COPD, and dementia over longer follow-up periods. The residual score method of computing social asymmetry and the grouping of social resilience and vulnerability has not, to our knowledge, been used in relation to mortality. However, we also created a 4 group classification developed by McHugh et al⁹ to categorize people as concordant or discordant with respect to the distributions of loneliness and social isolation. By linking the English Longitudinal Study of Aging (ELSA) with national Hospital Episode Statistics and mortality registry data, we tested the hypothesis that social asymmetry would be associated with greater future mortality risk and with greater incidence of CVD and CVD subtypes (coronary heart disease [CHD], stroke, and heart failure), COPD, and dementia. By contrast, we hypothesized that those with no or lower social asymmetry would have a lower risk.

Methods

Study Design and Sample

The study involved ELSA, a nationally representative panel study of men and women who were aged 50 years or older on recruitment, living in private households in England. The details of ELSA have been described in previous reports.²² In this study, we analyzed data at wave 4 (2008-2009) as our baseline because the number of participants with complete data on the exposures was larger than the earlier waves. This study was approved by Berkshire Research Ethics Committee and participants provided written informed consent. Our study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cohort studies.

Participants were excluded if they were lost to follow-up, did not consent the data linkage, were aged less than 50 years, or died before baseline. We also excluded participants with missing data on social asymmetry. For the analysis on morbidity, we further excluded those who had the corresponding disease at baseline evaluated by the self-reported questionnaire and health records (Figure 1).

Figure 1. — COPD indicates chronic obstructive pulmonary disease; CVD, cardiovascular disease.

Social Asymmetry

Social asymmetry scores were calculated using the residual score method described by Ong et al,¹⁰ regressing loneliness score (measured by the University of California, Los Angeles [UCLA] 3-item Loneliness Scale) onto social isolation scores (4-item scale involving contact with children, other relatives, and friends, as well as being a group member). The measurement of loneliness and social isolation are described in eMethods in Supplement 1. The residual score indicates the levels of loneliness that are not explained by social isolation. Social asymmetry scores were categorized into 2 groups: social vulnerability (residual score >0; feel lonelier than expected given their objective social isolation score) and social resilience (residual score ≤0; loneliness is lower than expected).

The score was further categorized into 4 groups that represent distinct patterns of social experience,⁹ namely concordant low lonely (social asymmetry scores falling within 1 SD of the mean and loneliness scores below the median; low loneliness and low isolation, aligned positive social experience), concordant high lonely (scores falling within 1 SD of the mean and loneliness scores above the median; high loneliness and high isolation; aligned negative social experience), discordant susceptible (scores more than 1 SD above the mean; high loneliness with low isolation), and discordant robust (scores falling at least 1 SD below the mean; low loneliness with high isolation). This classification allows examining how mismatches between subjective and objective social experiences are associated with health outcomes.

Measurement of Health Outcomes

Mortality was ascertained by linking the consenting ELSA participants to the National Health Service’s Central Registry for vital status data. CVD, COPD, and dementia cases were ascertained by linkage to hospital episode statistics data (HES), admitted patient care data, and HES outpatient data (details in eMethods in Supplement 1), by using the International Classification of Diseases, Ninth (ICD-9) and Tenth (ICD-10) Revisions. For the occurrence of CVD, events were censored at first CVD event of CHD, stroke, or heart failure, whichever came first. The most recent date of mortality was November 2024 and morbidity was March 2024.

Covariates

The covariates were selected with directed acyclic graphs (DAG) by using the DAGitty online tool and based on previous research.²³ These included age, sex, self-reported race (dichotomized in the survey as White or other race or ethnicity because of the small number of participants identifying as Asian, Asian British, Black, Black British, multi-ethnic, or any other ethnic group), education, wealth, marital status, smoking, alcohol consumption, physical activity, body mass index (BMI), and multimorbidity (details in eMethods in Supplement 1).

Statistical Analyses

The baseline characteristics are presented, overall and by social asymmetry category, as mean and SD or number and percentage as appropriate. Analysis of variance, Mann-Whitney U, or χ² tests were used to test the differences across groups.

The analysis was performed using a complete case analysis. The primary analyses modeled social asymmetry as continuous variable and a binary categorical variable. Kaplan-Meier method was used to estimate the risk of fatal event and incident morbidity, and differences in curves were tested by log-rank test. Cox proportional hazard regression models were used to estimate the hazard ratios (HRs) and 95% CIs for the associations. Proportional hazard assumptions were tested using Schoenfeld residual tests. Variation inflation factors were calculated to test the presence of multicollinearity among the variables. Three models were used: model 1 adjusted for age, sex, marital status, race, education, and wealth; model 2 additionally adjusted for smoking status, alcohol consumption, physical activity, and BMI; and model 3 additionally adjusted for multimorbidity. Five sensitivity analyses and subgroup analysis by sex were performed (eMethods in Supplement 1).

All analyses were conducted using R, version 4.3.2 (R Project for Statistical Computing) from April to August 2025. Two-tailed P values less than .05 were considered to indicate statistical significance.

Results

Participant Baseline Characteristics

A total of 7845 participants were included in the study. Their mean (SD) age was 65.5 (9.5) years, 4283 (54.6%) were women, 7694 (98.1%) were White, and 151 (1.9%) belonged to another racial or ethnic group (Table). For social asymmetry, 3101 (39.5%) were classified as socially vulnerable and 4744 (60.5%) were socially resilient; 3580 (45.6%) were classified as concordant low lonely, 2440 (31.1%) as concordant high lonely, 1448 (18.5%) as discordant susceptible, and 377 (4.8%) as discordant robust. The included sample was more likely to be more educated, male, White, married or cohabited, wealthier; to have higher BMI and physical activity; and to have lower loneliness and social isolation scores, but effect size estimates (Cohen d and Cramér V) indicated small between-group differences between included and excluded participants (eTable 1 in Supplement 1). The comparisons of baseline characteristics among different categories are shown in the Table and eTable 2 in Supplement 1.

Table. Baseline Characteristics of Participants.

Characteristic	Patients, No (%)			P value
	Overall (N = 7845)	Social asymmetry^a
	Overall (N = 7845)	Resilience (n = 4744)	Vulnerability (n = 3101)
Age, mean (SD), y	65.49 (9.50)	65.25 (9.17)	65.86 (9.97)	.01
Sex
Female	4283 (54.6)	2422 (51.1)	1861 (60.0)	<.001
Male	3562 (45.4)	2322 (48.9)	1240 (40.0)	<.001
Education group
No education	1935 (24.7)	1084 (22.9)	851 (27.5)	<.001
GCE/O-levels/NVQ 2	2530 (32.3)	1520 (32.1)	1010 (32.6)
NVQ 3/GCE/A-levels	654 (8.4)	389 (8.2)	265 (8.6)
Higher qualification/NVQ 4/NVQ 5/degree	2705 (34.6)	1736 (36.7)	969 (31.3)
Wealth quintile
1 (Lowest)	1537 (20.0)	790 (17.0)	747 (24.6)	<.001
2	1536 (20.0)	856 (18.4)	680 (22.4)
3	1536 (20.0)	947 (20.4)	589 (19.4)
4	1536 (20.0)	1008 (21.7)	528 (17.4)
5 (Highest)	1536 (20.0)	1043 (22.5)	493 (16.2)
Race
White	7694 (98.1)	4679 (98.6)	3015 (97.3)	<.001
Other^b	151 (1.9)	65 (1.4)	86 (2.7)	<.001
Marital status: married/cohabited	5465 (69.7)	3699 (78.0)	1766 (56.9)	<.001
Smoking status
Never	3127 (39.9)	1895 (40.0)	1232 (39.8)	<.001
Ever	3702 (47.3)	2291 (48.4)	1411 (45.6)
Current	1000 (12.8)	546 (11.5)	454 (14.7)
Alcohol: ≥5 d/wk	1834 (23.5)	1172 (24.8)	662 (21.5)	.001
PA
Low	2672 (34.1)	1464 (30.9)	1208 (39.0)	<.001
Moderate	3529 (45.0)	2189 (46.1)	1340 (43.2)
High	1644 (21.0)	1091 (23.0)	553 (17.8)
Multimorbidity	2895 (36.9)	1602 (33.8)	1293 (41.7)	<.001
BMI, mean (SD)^c	27.14 (7.55)	27.19 (6.85)	27.06 (8.51)	.49
UCLA loneliness score, mean (SD)	4.18 (1.53)	3.17 (0.37)	5.72 (1.33)	<.001
Social isolation score, mean (SD)	1.02 (1.08)	1.06 (1.06)	0.97 (1.12)	.001

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Abbreviations: BMI, body mass index; GCE, general certificate of education; NVQ, national vocational qualification; PA, physical activity; UCLA, University of California, Los Angeles.

^{^a}

Social resilience is defined as a residual score of 0 or lower. Social vulnerability is defined as a residual score lower than 0.

^{^b}

Other includes Asian, Asian British, Black, Black British, multi-ethnic, or any other ethnic group.

^{^c}

Calculated as weight in kilograms divided by height in meters squared.

Social Asymmetry and Mortality

Over a mean (SD) follow-up period of 13.6 (4.2) years, 2775 death cases were ascertained. Higher social asymmetry was associated with increased risk of all-cause mortality (HR, 1.04; 95% CI, 1.01-1.06) in the full adjustment model. Compared with those in the social resilience group, those in the social vulnerability group had a higher risk of all-cause mortality (HR, 1.13; 95% CI, 1.04-1.22) (Figure 2). The Kaplan-Meier curve showed increased mortality in the social vulnerability group (eFigure in Supplement 1) (χ²₁ = 34.4; P < .001). Compared with concordant low lonely, participants in the concordant high lonely (HR, 1.15; 95% CI, 1.05-1.25) and discordant susceptible (HR, 1.14; 95% CI, 1.03-1.28) categories showed an increased mortality risk. The finding was not significant for the discordant robust group (HR, 1.10; 95% CI, 0.91-1.32) in fully adjusted models (Figure 3).

Figure 2. — Social resilience was defined as residual score of 0 or lower and social vulnerability was defined as residual score greater than 0. Model 1 adjusted for age, sex, wealth, education, and marital status and ethnicity; model 2 additionally adjusted for smoking status, alcohol use, physical activity, and body mass index; model 3 additionally adjusted for long-term conditions. CHD indicates coronary heart disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; HR, hazard ratio.

Figure 3. — Model 1 adjusted for age, sex, wealth, education, marital status, and ethnicity; model 2 additionally adjusted for smoking status, alcohol use, physical activity, and body mass index; model 3 additionally adjusted for long-term conditions. Concordant low lonely is defined as social asymmetry scores falling within 1 SD of the mean and loneliness scores below the median indicating low loneliness, low isolation, and aligned positive social experience; concordant high lonely, scores falling within 1 SD of the mean and loneliness scores above the median indicating high loneliness, high isolation, and aligned negative social experience; discordant susceptible, scores more than 1 SD above the mean indicating high loneliness with low isolation; and discordant robust, scores falling at least 1 SD below the mean indicating low loneliness with high isolation. CHD indicates coronary heart disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; HR, hazard ratio.

Social Asymmetry and CVD

Of 6795 participants, 2415 developed CVD, and 1747 developed ischemic heart disease, 549 stroke, and 1026 heart failure over a mean 13.6-year follow-up. Higher social asymmetry was associated with increased risk of incident CVD (model 3: HR, 1.06; 95% CI, 1.02-1.10). The social vulnerability group showed a higher risk of CVD (HR, 1.16; 95% CI, 1.04-1.30) (Figure 2). Kaplan-Meier curves with a log-rank test showed a significant association (eFigure in Supplement 1) (χ²₁ = 15.9; P < .001). Participants in the concordant high lonely (HR, 1.20; 95% CI, 1.06-1.36) and discordant susceptible (HR, 1.27; 95% CI, 1.09-1.47) categories had an increased CVD risk, while the discordant robust group did not (Figure 3).

Social Asymmetry and COPD

Of 7552 participants with a mean (SD) 12.86 (4.23) years of follow-up, 989 (14.6%) developed COPD. Higher social asymmetry was associated with increased risk of COPD in models 1 and 2. However, after additionally adjusting for multimorbidity, there was no association (HR, 1.06; 95% CI, 0.99-1.10). Nevertheless, the socially vulnerable group showed a higher risk of COPD (HR, 1.21; 95% CI, 1.04-1.42) (Figure 2), and Kaplan-Meier curves showed a significant association (eFigure in Supplement 1) (χ²₁ = 19.5; P < .001). Only the concordant high lonely group (HR, 1.20; 95% CI, 1.00-1.44) had an increased COPD risk compared with the concordant low lonely reference group (Figure 3).

Social Asymmetry and Dementia

Of 7791 participants, 989 (12.7%) developed dementia during a mean (SD) of 13.03 (4.07) years of follow-up. Higher social asymmetry was associated with increased risk of dementia in model 1 and model 2. However, after further adjustment for multimorbidity, no association was found (HR, 1.05; 95% CI, 0.99-1.11). Social vulnerability showed no association in the full adjustment model (HR, 1.13; 95% CI, 0.96-1.32) (Figure 2). Compared with the concordant low lonely group, participants in the concordant high lonely (HR, 1.24; 95% CI, 1.03-1.49) and discordant robust group (HR, 1.31; 95% CI, 1.04-1.66) experienced an increased dementia risk. No association was observed in the discordant susceptible group in model 3.

Sensitivity Analysis

Inverse probability weighting analysis showed consistent findings for all outcomes except for no association of dementia in the concordant high lonely or discordant robust group (eTable 3 in Supplement 1). When excluding incident events within 1 year of follow-up, the association between social asymmetry and mortality became nonsignificant, but participants in the concordant high lonely group had an increased risk; social vulnerability remained significant for CVD (eTable 3 in Supplement 1). No effect modification between isolation and loneliness was found on any outcomes (eTable 4 in Supplement 1). Using a cutoff of 1 to define the social asymmetry group showed consistent findings for CVD and COPD (eTable 5 in Supplement 1). The E-values showed moderately robust to potential unmeasured confounding (eTables 6-7 in Supplement 1). Subgroup analysis by sex showed a significant association between concordant high lonely and discordant susceptible and all-cause mortality among men but not among women. Women but not men with social vulnerability had higher risk of CVD (eTable 8 in Supplement 1).

Discussion

Using ELSA, a representative cohort study of older adults with about 13-years of follow-up, we found higher social asymmetry (the discrepancy between loneliness and social isolation) was associated with increased risk of all-cause mortality, CVD, COPD, and dementia but not CVD subtypes. Social vulnerability, defined as negative social asymmetry scores, implying that individuals were lonelier than expected given their isolation status, was associated with an increased risk of all-cause mortality, CVD, heart failure, and COPD, when compared with social resilience. When further using a 4 category method, compared with the concordant low lonely group, participants in the concordant high lonely group had an increased risk for all health outcomes, while those in the discordant susceptible category had an increased risk for all-cause mortality and CVD. The discordant robust group showed no associations for all health outcomes except for dementia, where their risk was significantly elevated.

Although a large body of studies have examined social isolation and loneliness separately,^5,14,16,17 very few studies have combined the 2 constructs together to understand their health outcomes, such as mortality^18,24,25 and CVD,²⁶ and most studies have shown conflicting results. To our knowledge, this study is the first to investigate the association of social asymmetry and CVD, COPD, and dementia, and we found increased risk associated with higher social asymmetry and social susceptibility. Ong and colleagues¹⁰ proposed using the residual score to measure social asymmetry and found a significant association between social asymmetry scores using residual scores and physical health,¹¹ which is consistent with our findings showing negative association between social asymmetry and health. Higher social asymmetry means higher loneliness than predicted by isolation, and specifically, individuals with social vulnerability include those who feel lonely despite having high social connections (subjective loneliness or perceived social isolation) that are further linked to physical and mental health consequences.²⁷

The present study also found increased risk of mortality in in individuals who fell into concordant high lonely and discordant susceptible groups. A study based on the Irish Longitudinal Study on Aging found an increased risk of mortality among the concordant high lonely group and the discordant susceptible and robust group, compared with the concordant low lonely group.²¹ The findings were consistent with ours, except for the nonsignificant findings for the discordant robust group. The differences may be due to the different methods of social asymmetry. The residual score method may offer advantages for measuring social asymmetry by better capturing the discrepancy between loneliness and social isolation, and more effectively identifying individuals who are socially vulnerable or resilient. This study is the first we know of to report the association between different groups of social asymmetry and CVD, COPD, and dementia. The Women’s Health Initiative Extension Study II²⁶ found that women with both high social isolation and high loneliness scores had an approximately 13.0% to 27.0% higher risk of CVD than did women with low social isolation and low loneliness scores. The findings may explain the significant increased risk in the concordant high lonely group in our study. No association with CVD, mortality, and COPD in the discordant robust group may indicate that people who are isolated but not lonely are not at high risk. Steptoe et al²³ found that social isolation but not loneliness was associated with all-cause mortality, while a later analysis²⁸ reported that loneliness but not social isolation was linked with increased risk of CVD. Subsequently it was found that compared with people who were not isolated or lonely, persistent isolation and the combination of isolation and fluctuating loneliness over several years was related to all-cause mortality over a mean of 14 years.²⁹ Mortality and the incidence of CVD and COPD in the discordant robust group was not different from that of the concordant robust group. The discordant robust group included individuals who were not lonely despite having limited objective social connections. Solitude is not necessarily a negative experience, since being alone can allow people freedom to engage in their preferred activities without social constraints. Experience sampling studies have found that savoring being alone is associated with lower depression and loneliness.^30,31 However, it is notable that we found an increased risk of dementia in the discordant robust group compared with concordant low lonely group. This could be partly explained by the possibility that social isolation is more relevant to dementia risk than loneliness. A longitudinal study³² including 7761 participants showed social isolation but not loneliness was associated with cognitive decline, and the relationship of social isolation with cognitive decline was independent of loneliness. A UK Biobank study¹⁷ also showed the association between social isolation and dementia is independent of loneliness. Individuals with limited social connections may lack cognitive and social stimulation resulting from contact with others that may be protective for brain aging.³³ But caution should be taken in interpreting this association because of the unstable findings in the sensitivity analyses and small sample size of cases. More studies with larger sample size are needed.

Our findings add new evidence of the association between this new concept—social asymmetry—and a series of chronic disease and mortality from all causes and suggest that this metric may be useful to distinguish the effects of loneliness and social isolation on health-related outcomes. Our study found no interaction between social isolation and loneliness with mortality and morbidity, which was consistent with previous studies based on ELSA²³ and Health and Retirement Study and the Korean Longitudinal Study of Aging.³⁴ The findings further suggest that social isolation and loneliness are associated but distinct constructs, and combining these 2 measures to generate social asymmetry may provide additional value to understand the health effects. When using a stricter cutoff of 1, only some associations remained significant, further indicating the method of using 0 as cutoff may be better to identify individuals with substantial social asymmetry. Future replication work measuring social asymmetry using multiple operational definitions across additional datasets will add robustness and further confidence in these findings.

Strengths and Limitations

The strengths of this study include using a large-scale representative sample of older people in the UK, considering a series of potential confounders where depression was not adjusted because it was likely to be on the causal pathway from loneliness and/or social isolation and health outcomes,³⁵ having a long follow-up period, and ascertaining the health outcomes by linking the survey data to death records and in hospital and outpatient records. Future interventions could leverage this novel measurement to identify the distinct patterns of social experience and prioritize targeted psychological and social support for high-risk groups, particularly those experiencing social vulnerability, thereby informing policies to reduce social asymmetry and promote healthy aging.

This study also had limitations. First, although we have performed a series of sensitivity analyses, the findings for mortality and dementia were not consistent to the main analysis. Therefore, the findings should be interpreted with caution, and more studies are still needed to explore and validate the association between social asymmetry and health. Second, residual confounding cannot be ruled out, although we have adjusted for a variety of confounders. Third, our measures of loneliness and isolation, while validated, capture limited dimensions of these complex constructs. The UCLA scale focuses primarily on emotional aspects of loneliness, while our isolation measure combines structural and functional elements in ways that may obscure important distinctions. Fourth, the method to measure social asymmetry may not reflect true asymmetry because the association between social isolation and loneliness is probably not linear, and only using a 4-item scale may not fully distinguish the asymmetry. Moreover, the residual score and category approaches only indicate the extent of the social asymmetry but cannot identify universal cutoffs. Future studies are needed to develop robust methods of measuring social asymmetry and to identify and validate the meaningful cutoffs that are relevant for psychological and physical health. Categorization of social asymmetry based on population-specific standard deviations may have limited generalizability, although ELSA is designed to be representative of the English older population. Fifth, the present study did not take the dynamic change of loneliness and isolation into consideration because the main aim was to explore the association between baseline social asymmetry and health outcomes at follow-up. With more studies to validate the association between social asymmetry and health, future research is warranted to explore its dynamic effects.²⁹ Finally, prior loneliness or isolation patterns may also influence the sample inclusion. Individuals who had experienced loneliness or isolation in earlier waves but subsequently dropped out, or those whose patterns fluctuated before wave 4, may have been systematically excluded. However, due to the refreshment of wave 4 and limited sample size if considering the influence of waves 1 through 3, the present study did not consider the influence of this selection bias.

Conclusions

In this cohort study of people aged 50 years and over living in England, higher social asymmetry was associated with increased risk of incident morbidity and mortality, and social vulnerability was associated with increased risk of incident morbidity and mortality compared with social resilience. Our findings suggest it is important to evaluate both loneliness and isolation in studies of health outcomes and more efforts are needed to enhance social connections among older individuals, which could help to reduce the relevant disease burden.

Supplement 1.

eMethods.

eTable 1. Comparison of Baseline Characteristics Between Included and Excluded Participants

eTable 2. Baseline Characteristics of Participants by Different Categories of Social Asymmetry

eTable 3. Sensitivity Analyses for the Association of Social Asymmetry With Mortality and Morbidity

eTable 4. Sensitivity Analyses of Effect Modification Between Social Isolation and Loneliness on Mortality and Morbidity

eTable 5. Sensitivity Analyses of the Association of Social Asymmetry Group With Mortality and Morbidity When Using a Cutoff of 1 to Define Groups

eTable 6. Association of Social Asymmetry Score and Mortality and Morbidity, Taking Unmeasured Confounding Into Account

eTable 7. Association of Social Asymmetry Categories and Mortality and Morbidity Taking Unmeasured Confounding Into Account

eTable 8. Subgroup Analysis of Social Asymmetry and Mortality and Morbidity by Sex

eFigure. Kaplan-Meier Estimates of Cumutalative Indicence of Morbidity and Mortality by Baseline Social Asymmetry Group

jamanetwopen-e2558214-s001.pdf^{(635.1KB, pdf)}

Supplement 2.

Data Sharing Statement

jamanetwopen-e2558214-s002.pdf^{(19.6KB, pdf)}

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