All-cause mortality and three aspects of social relationships: an eight-year follow-up of older adults from one entire Korean village

Sex-specific modulating role of social support in the associations between oxidative stress, inflammation, and telomere length in older adults

Telomere length, a biomarker of human aging, is related to adverse health outcomes. Growing evidence indicates that oxidative stress and inflammation contributes to telomere shortening, whereas social support may protect from telomere shortening. Despite sex differences in telomere length and social support, little is known about whether there are sex differences in the relationship between oxidative stress/inflammation and telomere length, and sex-specific moderating roles of social support in older adults. Using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2002, this study assessed whether the associations between oxidative stress/inflammation and telomere length vary with sex and explored social support as a moderator in these associations among 2289 older adults. Oxidative stress was measured based on serum Gamma-glutamyl transferase (GGT), and inflammation was measured based on C-reactive protein (CRP). After adjusting for the covariates, GGT was significantly associated with telomere length in females only (β =  - 0.037, 95% CI =  - 0.070, - 0.005), while CRP was associated with telomere length in males only (β =  - 0.019, 95% CI =  - 0.035, - 0.002). Moreover, high social support mitigated the negative association between GGT and telomere length, which was more evident in females. Furthermore, social support moderated the association between CRP and telomere length in males aged 70 and above. Our findings indicated that biological mechanisms related to telomere length may vary with sex, while social support plays a sex-specific moderating role.

A Prospective Sociocentric Study of 2 Entire Traditional Korean Villages: The Korean Social Life, Health, and Aging Project (KSHAP)

The Korean Social Life, Health, and Aging Project (KSHAP) was a multidisciplinary prospective study conducted in South Korea that measured various health biomarkers from blood, hair, and brain magnetic resonance imaging, and we examined their associations with sociocentric (global) social network data of older adults in 2 entire villages (or cohorts). Cohort K included participants aged 60 years or older, and cohort L included participants aged 65 years or older. We performed a baseline survey involving 814 of the 860 individuals (94.7% response rate) in cohort K in 2012 and 947 of the 1,043 individuals (90.8% response rate) in cohort L in 2017. We gathered longitudinal data for 5 waves in cohort K from 2011 to 2019 and 2 waves in cohort L from 2017 to 2022. Here, we describe for the first time the follow-up design of the KSHAP, the changes in social networks, and various biomarkers over a number of years. The data for cohort K are publicly available via the Korean Social Science Data Archive as well as the project website, and the data for cohort L will be shared soon.

A meta-analysis of the association between loneliness and all-cause mortality in older adults

Despite the well-established association between loneliness and all-cause mortality in older adults, it remains unknown whether this association holds for older adults of different sex and whether it is influenced by different samples and study characteristics. Thus, this meta-analysis aims to examine moderators of the association between loneliness and all-cause mortality in older adults. To this end, relevant literature was retrieved from the PubMed, Embase, PsycINFO, Web of Science, Chinese National Knowledge Infrastructure, Weipu, and Wanfang databases (inception to May 2023) and was processed in the Comprehensive Meta-Analysis 3.3 software. Moreover, subgroup analysis was performed to explore the sources of heterogeneity and further explore potential moderators. Funnel plots, Begg's test, and Egger's linear regression test were used to examine the publication bias, and sensitivity analysis was used to test the robustness of the results. Thirty-six studies involving 128,927 older adults were included in this meta-analysis. In general, loneliness was related to an increase in all-cause mortality in older adults (HR = 1.09, 95% CI = 1.06-1.12, I2 = 63.31%, p < 0.001). The overall effect size for older men was 1.18 (95% CI = 1.04-1.33, p = 0.010). The association between loneliness and all-cause mortality was found to be significantly influenced by the source country of the data, follow-up length, and covariates for chronic disease as moderators. In conclusion, loneliness among older adults deserves more attention, and services are needed to improve their mental health.

A systematic review and meta-analysis of 90 cohort studies of social isolation, loneliness and mortality

The associations between social isolation, loneliness and the risk of mortality from all causes, cardiovascular disease (CVD) and cancer are controversial. We systematically reviewed prospective studies on the association between social isolation, loneliness and mortality outcomes in adults aged 18 years or older, as well as studies on these relationships in individuals with CVD or cancer, and conducted a meta-analysis. The study protocol was registered with PROSPERO (reg. no. CRD42022299959). A total of 90 prospective cohort studies including 2,205,199 individuals were included. Here we show that, in the general population, both social isolation and loneliness were significantly associated with an increased risk of all-cause mortality (pooled effect size for social isolation, 1.32; 95% confidence interval (CI), 1.26 to 1.39; P < 0.001; pooled effect size for loneliness, 1.14; 95% CI, 1.08 to 1.20; P < 0.001) and cancer mortality (pooled effect size for social isolation, 1.24; 95% CI, 1.19 to 1.28; P < 0.001; pooled effect size for loneliness, 1.09; 95% CI, 1.01 to 1.17; P = 0.030). Social isolation also increased the risk of CVD mortality (1.34; 95% CI, 1.25 to 1.44; P < 0.001). There was an increased risk of all-cause mortality in socially isolated individuals with CVD (1.28; 95% CI, 1.10 to 1.48; P = 0.001) or breast cancer (1.51; 95% CI, 1.34 to 1.70; P < 0.001), and individuals with breast cancer had a higher cancer-specific mortality owing to social isolation (1.33; 95% CI, 1.02 to 1.75; P = 0.038). Greater focus on social isolation and loneliness may help improve people's well-being and mortality risk.

Social relationship satisfaction and accumulation of chronic conditions and multimorbidity: a national cohort of Australian women

Background

Social relationships are associated with mortality and chronic conditions. However, little is known about the effects of social relationship satisfaction on multiple chronic conditions (multimorbidity).

Aims

To examine whether social relationship satisfaction is associated with the accumulation of multimorbidity.

Methods

Data from 7 694 Australian women who were free from 11 chronic conditions at 45-50 years of age in 1996 were analysed. Five types of social relationship satisfaction (partner, family members, friends, work and social activities) were measured approximately every 3 years and scored from 0 (very dissatisfied) to 3 (very satisfied). Scores from each relationship type were summed to provide an overall satisfaction score (range: ≤5-15). The outcome of interest was the accumulation of multimorbidity in 11 chronic conditions.

Results

Over a 20-year period, 4 484 (58.3%) women reported multimorbidities. Overall, the level of social relationship satisfaction had a dose-response relationship with the accumulation of multimorbidities. Compared with women reporting the highest satisfaction (score 15), women with the lowest satisfaction (score ≤5) had the highest odds of accumulating multimorbidity (odds ratio (OR)= 2.35, 95% confidence interval (CI): 1.94 to 2.83) in the adjusted model. Similar results were observed for each social relationship type. Other risk factors, such as socioeconomic, behavioural and menopausal status, together explained 22.72% of the association.

Conclusions

Social relationship satisfaction is associated with the accumulation of multimorbidity, and the relationship is only partly explained by socioeconomic, behavioural and reproductive factors. Social connections (eg, satisfaction with social relationships) should be considered a public health priority in chronic disease prevention and intervention.

The Effect of Cognitive Impairment on the Association Between Social Network Properties and Mortality Among Older Korean Adults

OBJECTIVES

This study investigated the effect of cognitive impairment on the association between social network properties and mortality among older Korean adults.

METHODS

This study used data from the Korean Social Life, Health, and Aging Project. It obtained 814 older adults' complete network maps across an entire village in 2011-2012. Participants' deaths until December 31, 2020 were confirmed by cause-of-death statistics. A Cox proportional hazards model was used to assess the risks of poor social network properties (low degree centrality, perceived loneliness, social non-participation, group-level segregation, and lack of support) on mortality according to cognitive impairment.

RESULTS

In total, 675 participants (5510.4 person-years) were analyzed, excluding those with missing data and those whose deaths could not be verified. Along with cognitive impairment, all social network properties except loneliness were independently associated with mortality. When stratified by cognitive function, some variables indicating poor social relations had higher risks among older adults with cognitive impairment, with adjusted hazard ratios (HRs) of 2.12 (95% confidence interval [CI], 1.34 to 3.35) for social nonparticipation, 1.58 (95% CI, 0.94 to 2.65) for group-level segregation, and 3.44 (95% CI, 1.55 to 7.60) for lack of support. On the contrary, these effects were not observed among those with normal cognition, with adjusted HRs of 0.73 (95% CI, 0.31 to 1.71), 0.96 (95% CI, 0.42 to 2.21), and 0.95 (95% CI, 0.23 to 3.96), respectively.

CONCLUSIONS

The effect of social network properties was more critical among the elderly with cognitive impairment. Older adults with poor cognitive function are particularly encouraged to participate in social activities to reduce the risk of mortality.

Loneliness, social network size and mortality in older adults: a meta-analysis

Loneliness and social network size have been found to be predictors of mortality in older adults. The objective of this study was to investigate whether loneliness and small social network size are associated with an increased mortality risk and to review the evidence for either network size, or loneliness that constitutes the higher mortality risk. A systematic literature search was performed in PubMed, EMBASE and PsychInfo in January/February 2018 and March/April 2021. Studies that mentioned outcome data were included in the meta-analysis and coded using the Newcastle-Ottawa Quality Assessment Scale for Cohort Studies. The meta-analysis showed that both loneliness and small social network size are associated with mortality risk in older adults (Hazard Ratio 1.10 (95% Confidence Interval 1.06-1.14) for loneliness and 0.96 (95% Confidence Interval 0.93-0.99) for larger network size). Sensitivity analyses according to the Newcastle-Ottawa Quality Assessment Scale yielded varying results. Heterogeneity was large. In conclusion, both loneliness and small social network size in older adults are associated with increased mortality, although the effect size is small. Targeting subjective and objective aspects of older adults' social contacts should be on the agenda of preventive as well as personalized medicine. In order to be able to compare the association between loneliness and network size and mortality, more studies are needed that include both these risk factors.