Associations of face-to-face and non-face-to-face social isolation with all-cause and cause-specific mortality: 13-year follow-up of the Guangzhou Biobank Cohort study

Evaluation of Changes in Social Isolation and Loneliness with Incident Cardiovascular Events and Mortality

BACKGROUND

It remains unknown how the patterns of change of social isolation and loneliness are associated with the onset of cardiovascular disease (CVD) and mortality. We aimed to investigate the longitudinal association of changes in social isolation and loneliness with incident CVD, all-cause mortality, CVD mortality and subsequent cardiac function.

METHODS

This prospective cohort study included 18,258 participants aged 38-73 years who participated in visit 0 (2006-2010) and visit 1 (2012-2013) using UK Biobank (mean age 57.1, standard deviation [SD] 7.4; 48.7% males). Social isolation or loneliness was categorized into four patterns: never, transient, incident, and persistent. Incident CVD, all-cause and CVD mortality were ascertained through linkage data. Cardiac function was assessed by cardiovascular magnetic resonance imaging in a subsample (N = 5188; visit 2, since 2014).

RESULTS

Over a median follow-up of 8.3 (interquartile range [IQR] 8.1-8.6) years, compared with never social isolation, persistent social isolation was associated with the higher risk of incident CVD (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.03-1.33), all-cause (1.42, 1.12-1.81) and CVD (1.53, 1.05-2.23) mortality. Likewise, persistent loneliness was strongly associated with the greater risk of incident CVD (1.13, 1.00-1.27), all-cause (1.28, 1.02-1.61) and CVD mortality (1.52, 1.06-2.18).

CONCLUSIONS

Persistent social isolation and loneliness posed a substantially higher risk for incident CVD, all-cause and CVD mortality, and cardiac dysfunction than other patterns. Persistent social isolation and loneliness, along with an increasing cumulative score, are associated with lower cardiac function.

Regular exercise reduces the risk of all-cause mortality in socially isolated older adults: the Otassha Study

Introduction

Social isolation is associated with increased mortality risk. On the other hand, some older adults prefer to be alone. Additionally, predictors of isolation are mostly unchanged across interventions. Therefore, knowledge of how to prevent negative health outcomes in isolation would be beneficial. One of the factors that reduces the risk of mortality is regular exercise. However, to date, no studies to our knowledge have examined whether regular exercise reduces mortality among socially isolated individuals. This study aimed to determine the effects of the combination of social isolation and regular exercise on mortality among community-dwelling older adults.

Methods

This prospective cohort study was part of the larger Otassha Study of community-dwelling older adults living in Itabashi Ward, Tokyo, Japan. In October 2012, 835 individuals (males = 350, females = 485; mean age 73.1 years) completed a comprehensive baseline health survey. Individuals were considered socially isolated if their frequency of interactions with others averaged less than once per week. Regular exercise was defined as exercise performed at least twice a week. The participants were assigned to one of the following four groups: (1) not isolated with regular exercise, (2) not isolated without regular exercise, (3) isolated with regular exercise, and (4) isolated without regular exercise. All-cause mortality information was obtained from the ward office database. Follow-ups were conducted until 1 November 2020. A Cox proportional regression analysis was performed.

Results

A final analysis was performed on a complete dataset of 735 participants (males = 303, females = 432; mean age 72.9 years). A total of 132 (18.0%), 426 (58.0%), 27 (3.7%), and 150 (20.4%) participants were assigned to groups 1, 2, 3, and 4, respectively. The mortality rates in groups 1, 2, 3, and 4 were 6.1%, 9.2%, 7.4%, and 19.3%, respectively. Compared with group 1, isolated individuals who did not perform regular exercise had a significantly higher mortality rate [adjusted hazard ratio (aHR), 2.48; 95% confidence interval (CI), 1.12-5.52]. However, no significant association was noted in isolated individuals who performed regular exercise (aHR, 1.25; 95% CI, 0.26-5.91).

Conclusion

Regular exercise was associated with a decrease in mortality risk, regardless of social isolation status. Thus, our results indicate that encouraging isolated older adults to exercise regularly may reduce their negative health outcomes.

Loneliness impact on healthcare utilization in primary care: A retrospective study

BACKGROUND

An increased number of patients seek help for loneliness in primary care.

OBJECTIVE

To analyze whether loneliness was associated with a higher utilization of healthcare facilities.

METHODS

Observational, retrospective study based on the review of routinely coded data in the digital medical record system in a random sample of patients aged 65 or older, stratified by population size of their residence area. A minimum sample size was estimated at 892 medical records. Loneliness was defined as the negative feeling that arises when there is a mismatch between the quantity and quality of a person's social relationships and those, they desire. Thirty-three primary care nurses (30 females and 3 males) were reviewing the data.

RESULTS

A total of 932 medical records of patients were reviewed (72% belonged to female patients). Of these, 657 individuals were living alone (71.9%). DeJong Scale average scores was 8.9 points (SD 3.1, 95CI 8.6-9.1). The average annual attendance to primary care ranged from 12.2 visits per year in the case of family practice, 10.7 nurse, 0.7 social workers. The average number of home visits was 3.2, and the urgent consultations attended at health centers were 1.5 per year. Higher feelings of loneliness were associated with extreme values in the frequency of healthcare resource usage. Compared to their peers of the same age, the additional healthcare resource consumption amounted to €802.18 per patient per year.

CONCLUSION

Loneliness is linked to higher healthcare resource usage in primary care, with individuals experiencing poorer physical and mental health utilizing these resources up to twice as much as their peers of the same age.

Social isolation, regardless of living alone, is associated with mortality: the Otassha study

Introduction

Social isolation has been recognized as a contributing factor to negative health outcomes. Although living alone is associated with health-related outcomes, existing findings are inconsistent. It is not the act of living alone that may predict poor health, but rather social isolation that can lead to increased mortality risk. This study investigated the combined associations of social isolation and living alone with mortality among community-dwelling older adults.

Methods

We included older adults from Itabashi ward, Tokyo, who participated in comprehensive health checkups. Participants were categorized into four groups based on their social isolation status and living alone. The primary outcome was all-cause mortality, analyzed using Cox proportional hazards models.

Results

Of the 1,106 participants (mean age 73, 42% male), 4.5% experienced both social isolation and living alone. This combination was associated with a worse prognosis regarding all-cause mortality (hazard ratio (HR): 2.08 [95% confidence interval (CI), 1.08-4. 00]). Those who were socially isolated but not living alone also showed a trend towards higher mortality risk (HR: 1.41 [95% CI, 0.90-2.20]). Contrastingly, those who were not socially isolated and lived alone did not show an increased mortality risk (HR: 0.81 [95% CI, 0.44-1.49]).

Discussion and conclusion

Living alone is not inherently associated with a poor prognosis in older adults; however, social isolation was associated with a higher mortality risk. Healthcare providers should focus on enhancing social interactions and support for older adults because of their effects on health rather than solely addressing living arrangements to prevent adverse health events.

Associations of daytime napping and nighttime sleep quality with depressive symptoms in older Chinese: the Guangzhou biobank cohort study

BACKGROUND

Poor sleep quality has been linked to depression in older adults, but results of the association between daytime napping and depression remains limited and conflicting. Moreover, whether the association of daytime napping with depression varies by nighttime sleep quality is unclear. Hence, we examined the associations of daytime napping and nighttime sleep quality with depressive symptoms in older Chinese.

METHODS

A total of 16,786 participants aged ≥50 from the Guangzhou Biobank Cohort Study second-round examination (2008-2012) were included in this cross-sectional study. Geriatric Depression Scale (GDS-15), Pittsburgh Sleep Quality Index (PSQI), napping and demographic data were collected by face-to-face interview using a computerized questionnaire. Logistic regression was used to calculate odds ratio (OR) of depressive symptoms for napping and sleep quality.

RESULTS

The prevalence of depressive symptoms (GDS score > 5) and poor global sleep quality (PSQI score ≥ 6) was 5.3 and 31.9%, respectively. Compared to non-nappers, nappers showed significantly higher odds of depressive symptoms, with OR (95% confidence interval (CI)) being 1.28 (1.11-1.49). The odds of depressive symptoms for daytime napping varied by nighttime sleep quality (P for interaction = 0.04). In good-quality sleepers, compared to non-nappers, nappers had significantly higher odds of depressive symptoms, with OR (95% CI) being 1.57 (1.23-2.01), whereas no association was found in poor-quality sleepers (OR = 1.13, 0.94-1.36).

CONCLUSION

Napping was associated with higher odds of depressive symptoms in older people, and the association was stronger in good-quality sleepers.

Persistence of social isolation and mortality: 10-year follow-up of the Guangzhou Biobank Cohort study

Although social isolation has been associated with higher mortality risk, the associations of persistence of social isolation with mortality are unclear. We investigated the prospective associations of intermittent and persistent social isolation with all-cause and cause-specific mortality, considering the social contact types (face-to-face and non-face-to-face). 30,518 participants were recruited in 2003-2008 initially and 18,104 participants with re-assessed social isolation information in 2008-2012 were followed up to Dec 2019 in Guangzhou Biobank Cohort Study (GBCS). During an average of 9.7 years of follow-up, 2,119 deaths occurred. The isolation at baseline survey, isolation at second survey and persistent isolation were positively associated with all-cause mortality in the minimal adjusted model (adjusted hazard ratio (AHR) =1.24, 95% CI 1.12-1.38, 1.11, 1.00-1.23 and 1.23, 1.05-1.43, respectively). Totally 47.2% of the risk was explained by health status, SEP, and biological, behavioural and psychological factors. Persistent isolation from face-to-face with co-inhabitants, versus no isolation, was associated with higher risks of all-cause (HR=1.40, 1.09-1.81) and CVD (subdistribution hazard ratio (SHR)=1.92, 1.31-2.81) mortality in fully adjusted model. Our study showed that intermittent and persistent isolation were generally associated with higher risks of mortality, and the risks were even higher in those with persistent face-to-face isolation with co-inhabitants.

Genetic loci, rs17817449 and rs6567160, known for obesity and the risk of stroke events among middle-aged and older Chinese people

BACKGROUND

Fat Mass and Obesity-Associated (FTO) and the Melanocortin-4 Receptor (MC4R) genes are strongly associated with obesity, an established risk factor for stroke. We aimed to assess the associations between rs17817449 at the FTO and rs6567160 at the MC4R and the risk of stroke events in middle-aged and older Chinese people.

MATERIALS AND METHODS

Study data were obtained from the Guangzhou Biobank Cohort Study; a total of 148 participants with a self-reported history of stroke and an equal volume of age- and sex-matched participants were selected as the cases and the controls in a case-control study; a total of 13,967 participants at the first follow-up and all participants with fatal stroke (up to April 2021) were included in a retrospective cohort study. Conditional logistic regression and the Cox proportional hazards regression analyses were used to assess the associations of the two genetic loci with the risk of stroke events.

RESULTS

After adjusting for age, sex, education, job, smoking, alcohol consumption, body mass index, physical activity, hypertension, diabetes, and dyslipidemia, rs17817449 and rs6567160 shared minor alleles G and C, respectively, in the case-control analyses. The genotypes GG+GT of rs17817449 at the FTO were significantly associated with a decreased risk of fatal stroke occurrence, with fatal all strokes having an adjusted hazard ratio (aHR) of 0.71 (95% confidence intervals (CI) 0.52-0.97, P = 0.04) and fatal ischemic stroke having an aHR of 0.64 (95% CI 0.41-1.00, P = 0.05), when the genotype TT was taken as a reference and a series of multiplicities were adjusted; the risk of fatal all strokes was lowered by dyslipidemia (aHR = 0.63, 95% CI 0.39-1.00, P = 0.05) and non-diabetes (aHR = 0.68, 95% CI 0.46-0.99, P = 0.049) in the retrospective cohort analyses. Significances were observed neither in the associations between rs6567160 and the risk of stroke events nor in an interaction between rs17817449 and rs6567160 in the two-stage analyses.

CONCLUSION

The G allele of rs17817449 at the FTO, not rs6567160 at the MC4R, was associated with a decreased risk of fatal stroke occurrence; its functional role in stroke should be explored in relatively healthy middle-aged to older Chinese people.

Chronotype and cognitive function: Observational study and bidirectional Mendelian randomization

BACKGROUND

Association has been found between chronotype and cognitive function in conventional observational studies but whether this association is causal and if so, its direction, is uncertain. There are also concerns among people with later chronotype that their habits may be detrimental to cognitive function.

METHODS

We analyzed the association between chronotype (measured as sleep midpoint) and cognitive function (measured by Mini-Mental Status Examination (MMSE) and Delayed Word Recall Test (DWRT)) using multivariable linear regression on 14,582 participants in the Guangzhou biobank cohort study (GBCS) from 2008 to 2012. Using bidirectional Mendelian randomization, we used 207 single nucleotide polymorphisms (SNPs) associated with chronotype from the combination of UK Biobank and 23andMe (n = 697,828), and 127 SNPs associated with cognitive function from the combination of UK Biobank and COGENT consortium (n = 257,841).

FINDINGS

Observationally in GBCS, later chronotype was associated with better cognitive function (MMSE scores: β = 0.14 per hour; 95% confidence interval (CI), 0.09-0.19; DWRT scores: β = 0.07 per hour; 95% CI, 0.04-0.11). Bidirectional MR showed genetic predisposition to early, versus later, chronotype was not associated with cognitive function using inverse-variance weighted (β = -0.02; 95% CI, -0.05 to 0.01). However, better cognitive function was associated with decreased odds of early chronotype (UK Biobank: odds ratio = 0.88 per standardized score; 95% CI, 0.83-0.93; 23andMe: 0.87 per standardized score; 95% CI, 0.80-0.95).

INTERPRETATION

It is a reassuring finding for adults with later chronotype who may be concerned if such a habit has a negative impact on cognitive function.

FUNDING

The National Natural Science Foundation of China; Natural Science Foundation of Guangdong; The University of Hong Kong Foundation for Educational Development and Research; The Health Medical Research Fund in Hong Kong; The University of Birmingham, UK.

Hearing loss and depressive symptoms in older Chinese: whether social isolation plays a role

Background

Existing evidence links hearing loss to depressive symptoms, with the extent of association and underlying mechanisms remaining inconclusive. We conducted a cross-sectional study to examine the association of hearing loss with depressive symptoms and explored whether social isolation mediated the association.

Methods

Eight thousand nine hundred sixty-two participants from Guangzhou Biobank Cohort Study were included. Data on self-reported hearing status, the 15-item Geriatric Depression Scale (GDS-15), social isolation and potential confounders were collected by face-to-face interview.

Results

The mean (standard deviation) age of participants was 60.2 (7.8) years. The prevalence of poor and fair hearing was 6.8% and 60.8%, respectively. After adjusting for age, sex, household income, education, occupation, smoking, alcohol use, self-rated health, comorbidities, compared with participants who had normal hearing, those with poor hearing (β = 0.74, 95% confidence interval (CI) 0.54, 0.94) and fair hearing (β = 0.59, 95% CI 0.48, 0.69) had higher scores of GDS-15. After similar adjustment, those with poor hearing (odds ratio (OR) = 2.13, 95% CI 1.65, 2.74) or fair hearing (OR = 1.68, 95% CI 1.43, 1.99) also showed higher odds of depressive symptoms. The association of poor and fair hearing with depressive symptoms attenuated slightly but not substantially after additionally adjusting for social isolation. In the mediation analysis, the adjusted proportion of the association mediated through social isolation was 9% (95% CI: 6%, 22%).

Conclusion

Poor hearing was associated with a higher risk of depressive symptoms, which was only partly mediated by social isolation. Further investigation of the underlying mechanisms is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03311-0.