Association Between Social Isolation and Smoking in Japan and England

Does Tobacco Smoking Increase Social Isolation? A Mendelian Randomization Study

In this study, we aimed to investigate the causal effect of smoking on social isolation among older adults in England. Data from older adults of European ancestry who participated in 1 or more waves of the English Longitudinal Study of Ageing, from wave 1 (2002/2003) to wave 9 (2018/2019), were analyzed (n = 43,687 observations from 7,008 individuals; mean age = 68.50 years). The effect of current smoking on social isolation (ranging from 0 to 5) was estimated by 2-stage least squares regression using a polygenic score (PGS) for smoking cessation as the instrument. A low PGS for smoking cessation predicted current smoking (per 1-standard-deviation lower PGS, coefficient = 0.023, 95% confidence interval (CI): 0.015, 0.030; F = 36.420). The second-stage regression showed that current smoking increased social isolation by 1.205 points (95% CI: 0.308, 2.101). The association was larger for persons with higher socioeconomic backgrounds: 2.501 (95% CI: -0.024, 5.026) and 0.696 (95% CI: -0.294, 1.686) for those with higher and lower educational levels, respectively. This study showed that current smoking instrumented by a PGS for smoking cessation was associated with social isolation. Assuming that the PGS served as a valid instrument in this study, the findings support an effect of smoking on social isolation.

Cultural engagement and prevalence of pain in socially isolated older people: a longitudinal modified treatment policy approach

Background

It remains uncertain whether cultural engagement positively influences the reduction of pain risk, particularly depending on the social isolation status. The aim of this study was to examine the impact of cultural engagement on the reduction of pain prevalence over a 6-year follow-up period among older people, particularly those experiencing different dimensions of social isolation.

Methods

This study was a prospective longitudinal study. We analysed the English Longitudinal Study of Ageing cohort, consisting of 6468 community-dwelling adults aged ≥50 years old who provided data in waves 6 (2012-2013), 7 (2014-2015), 8 (2016-2017), and 9 (2018-2019). Self-reported cultural engagement (going to museums, art galleries, exhibitions, the theatre, concerts, or the opera) measured in waves 6-8 was used as the exposure variable. Meanwhile self-reported moderate-to-severe pain in wave 9 was used as the outcome variable. Social isolation was considered in waves 6-8, and the possibility of effect modification was captured by assessing each component of the social isolation index: not married or cohabiting with a partner, fewer than monthly contact with children/other immediate family/friends, and not engaging in any organisations, religious groups, or committees.

Findings

The estimated pain prevalence was 29.2% (95% confidence interval, 28.1-30.3; reference) after adjusting for time-variant, time-invariant, and loss to follow-up factors. Cultural engagement led to a reduction in pain prevalence to 24.1% for all individuals, representing a decrease of 5.1% (95% confidence interval, 0.6-9.6; P-value, 0.03). In older people who were not married or cohabiting, cultural engagement resulted in a decrease in pain prevalence to 25.8%, a reduction of 3.4% (95% confidence interval, 0.4-6.4; P-value, 0.01). For those with less frequent contact with close family members, the pain prevalence decreased to 25.3%, a reduction of 3.9% (95% confidence interval, 0.2-7.6; P-value, 0.03). Meanwhile, other dimensions of social isolation did not show a significant reduction in pain prevalence.

Interpretation

Cultural engagement may help to reduce the risk of pain in socially isolated older adults. Those who were single or living alone and had less frequent contact with immediate family were particularly vulnerable. While cultural engagement might help certain socially isolated older people feel better, its effectiveness varies, highlighting the need for targeted interventions.

Funding

The Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number (22K17648, Ikeda).

General self-efficacy, not musculoskeletal health, was associated with social isolation and loneliness in older adults during the COVID-19 pandemic: findings from the Hertfordshire Cohort Study

BACKGROUND

Social isolation and loneliness are prevalent among older adults. This study investigated factors influencing worsening social isolation and loneliness in community-dwelling older adults during the COVID-19 pandemic, focusing on musculoskeletal conditions, falls, and fractures.

METHODS

We studied 153 participants from the Hertfordshire Cohort Study. Baseline assessments (2019-20) included osteoporosis, clinical osteoarthritis, fractures after age 45 years, falls in previous year, and lifestyle factors. Self-efficacy was assessed using a shortened General Self-Efficacy Scale. Social isolation was assessed using the 6-item Lubben Social Network Scale. Follow-up (2020-21) assessments included social isolation and loneliness using the 6-item De Jong-Gierveld scale for emotional, social, and overall loneliness.

RESULTS

Baseline median age was 83.1 years. A history of smoking predicted worsening social isolation (p = 0.046). Being married (p = 0.026) and higher self-efficacy scores (p = 0.03) predicted reduced social isolation at follow-up. Greater alcohol consumption was associated with higher overall loneliness (p = 0.026). Being married was related to a 36% (95% CI: 3%, 58%) reduction in emotional loneliness (p = 0.037). No musculoskeletal condition was associated with social isolation or loneliness. However, we observed a 22% (14%, 30%; p < 0.001) reduction in emotional loneliness and a 12% (4%, 20%; p = 0.003) reduction in overall loneliness per unit increase in self-efficacy score.

CONCLUSIONS

No musculoskeletal condition was associated with increased social isolation or loneliness, but longitudinal studies in larger samples are required. Greater self-efficacy was associated with reduced social isolation and reduced loneliness. Interventions promoting self-efficacy in older adults may reduce isolation and loneliness in this age group.

Social Isolation and Worsening Health Behaviors Among Older Adults During the COVID-19 Pandemic

OBJECTIVES

We examine the relationship between social isolation, poor health behaviors, and the perceived worsening of older adults' health behaviors following the coronavirus outbreak. We assess the extent to which psychological pathways mediate the relationship between social isolation and worsening health behaviors.

METHODS

Drawing on data from the National Social Life Health and Aging Project Round 3 (2015) and its coronavirus immune disease 2019 (COVID-19) substudy (2020; N = 2,549), we use generalized linear models to explore how indicators of social isolation during the COVID-19 pandemic-infrequent in-person contact with friends and family in 2020 and decreased in-person contact with friends and family since COVID-19 started-are associated with (1) poor health behaviors (low physical activity, drinks per week, smoking, and poor sleep) in 2020 and (2) perceived worsening of health behaviors (reports of decreased physical activity, increased drinking and smoking, and feeling less rested) since the pandemic started.

RESULTS

Infrequent in-person contact was not associated with poor health behaviors. Decreases in in-person contact, on the other hand, were associated with worsening health behaviors. Older adults who reported decreases in in-person contact were more likely to perceive a decrease in physical activity, an increase in drinking, and feeling less rested. Emotional well-being, particularly loneliness compared to anxiety or depressive feelings, partially mediated the relationship between perceived worsening of health behaviors and a decrease in in-person contact with friends, and to a lesser extent, with family.

DISCUSSION

Our study suggests that in-person contact may play a distinct role in shaping older adults' well-being during the pandemic.

Social isolation, loneliness, and incident type 2 diabetes mellitus: results from two large prospective cohorts in Europe and East Asia and Mendelian randomization

Background

Social isolation and loneliness pose significant public health challenges globally. The objective of this study is to investigate the association between social isolation, loneliness, and the risk of type 2 diabetes mellitus (T2DM).

Methods

423,503 UK adults from the UK Biobank (UKB) and 13,800 Chinese adults from the China Health and Retirement Longitudinal Study (CHARLS) were analyzed. The exposures of interest were social isolation and loneliness. Social isolation was evaluated based on the number of household members, frequency of social activities, contact with others, and marriage status (CHARLS only). Loneliness was evaluated by the subjective feeling of loneliness and the willingness to confide in others (UKB only). The primary endpoint was incident T2DM. The two-sample Mendelian randomization (MR) analysis was based on the genome-wide association studies of UKB (n = 463,010) and the European Bioinformatics Institute (n = 655,666).

Findings

The UKB cohort study documented 15,072 T2DM cases during a mean follow-up of 13.5 years, and the CHARLS cohort study recorded 1,249 T2DM cases during a mean follow-up of 5.8 years. Social isolation and loneliness showed significant associations with an elevated risk of T2DM in both UKB (social isolation [most vs least]: HR 1.17, 95% CI 1.11-1.23; loneliness [yes vs no]: HR 1.21, 95% CI 1.13-1.30) and CHARLS cohorts (social isolation [yes vs no]: HR 1.22, 95% CI 1.06-1.40; loneliness [yes vs no]: HR 1.21, 95% CI 1.07-1.36). These associations remained significant after accounting for baseline glucose status and genetic susceptibility to T2DM. Two-sample MR analyses determined that feeling lonely (OR 1.04, 95% CI 1.02-1.06) and engaging in fewer leisure/social activities (OR 1.03, 95% CI 1.02-1.05) were associated with increased T2DM risk, whereas more contact with friends or family (OR 0.99, 95% CI 0.98-0.99) was associated with reduced T2DM risk.

Interpretation

Social isolation and loneliness are each associated with an elevated risk of T2DM, with MR analyses suggesting potential causal links. These associations remain significant after considering genetic susceptibility to T2DM. The findings highlight the importance of promoting initiatives to address social isolation and loneliness as part of T2DM prevention strategies.

Funding

CAMS Innovation Fund for Medical Sciences (No. 2021-I2M-1-008) and National Natural Science Foundation of China (No. 72103187).

Assessing the impacts of smoking cessation and resumption on back pain risk in later life

BACKGROUND

This study aimed to assess the impacts of smoking cessation and resumption over 4 years on the risk of back pain at the 6-year follow-up among older adults in England.

METHODS

We analysed 6467 men and women aged ≥50 years in the English Longitudinal Study of Aging. Self-reported smoking status, assessed in waves 4 (2008-2009) and 6 (2012-2013), was used as exposure for the study, whereas self-reported back pain of moderate or severe intensity, assessed in wave 7 (2014-2015), was used as the outcome. A targeted minimum loss-based estimator was used with longitudinal modified treatment policies to adjust for baseline and time-varying covariates.

RESULTS

Regarding the estimation of the effects of changes in smoking status on the risk of back pain, during the follow-up, individuals who resumed smoking within 4 years had a higher risk of back pain than those who avoided smoking for over 4 years, and the relative risk (RR) (95% confidence interval [CI]) was 1.536 (1.214-1.942). Regarding the estimation of effects of smoking cessation on the risk of back pain, smoking cessation over 4 years was associated with a significantly lower risk of back pain, as indicated by the originally observed data, and the RR (95% CI) was 0.955 (0.912-0.999).

CONCLUSIONS

Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain.

SIGNIFICANCE

Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain. Our study data suggest the importance of maintaining smoking cessation to reduce the risk of back pain in the older population.

Social isolation, loneliness, and their correlates in older Japanese adults

BACKGROUND

Loneliness and social isolation are elevated in older adults and associated with a range of detrimental outcomes. Despite this, there has been little research on these phenomena or on similarities and differences in their occurrence or combination in older Japanese adults. The current study aims to (i) determine what factors are associated with social isolation and loneliness among older adults in Japan; and (ii) describe the characteristics of individuals who are socially isolated but not lonely, as well as those who feel lonely but are not socially isolated.

METHODS

Data were analysed from 13 766 adults aged ≥65 years who participated in the 2019 wave of the Japan Gerontological Evaluation Study. Poisson regression analysis was used to examine associations.

RESULTS

Among older Japanese adults, the attributes of higher age, male gender, lower socioeconomic status, being a welfare recipient, and having depressive symptoms were associated with social isolation, while lower socioeconomic status, unemployment, welfare receipt, and poor physical and mental health were associated with loneliness. In addition, better educated, and mentally and physically healthy people were less likely to feel lonely even when socially isolated, while people who were not working and who had mental or physical health problems were more likely to feel lonely even if they were not socially isolated.

DISCUSSION

Our results indicate that in order to reduce unwanted social isolation and loneliness among older Japanese adults, in the first instance the focus should be on those individuals who are socioeconomically disadvantaged and unhealthy.

Does remaining teeth and dental prosthesis associate with social isolation? A six-year longitudinal study from the Japan Gerontological Evaluation Study (JAGES)

OBJECTIVES

Social isolation was associated with increased mortality and numerous adverse health outcomes. However, the longitudinal association between oral health and social isolation has not been studied. In this longitudinal prospective cohort study, the association between the number of remaining teeth and dental prosthesis use with social isolation after 6-years follow-up was examined.

METHODS

Functionally independent adults aged 65 years or older, who were not socially isolated in 2010, were followed up until 2016 in the Japan Gerontological Evaluation Study. Data from 26 417 participants were analysed after random forest imputation to address missing data. Logistic regression models were used to calculate the odds ratio (OR) for incident social isolation in 2016 after adjusting for age, sex, educational attainment, income, activities of daily living, living area and having depressive symptoms.

RESULTS

The mean age of the participants at baseline was 72.3 (SD = 5.0). A total of 1,127 (4.3%) participants were socially isolated at follow-up. Of these, 338 (3.2%) had ≥20 teeth (with or without using dental prosthesis), 171 (3.9%) had 10-19 teeth and used dental prosthesis, 112 (4.2%) had 10-19 teeth and did not use the dental prosthesis, 338 (5.1%) had 0-9 teeth and used dental prosthesis, and 168 (7.6%) had 0-9 teeth and did not use the dental prosthesis. Fully adjusted logistic regression models showed that the OR of incident social isolation was higher for those with fewer teeth; OR = 1.13 (95%CI = 0.96-1.33) for those with 10-19 teeth and OR = 1.36 (95%CI = 1.17-1.58) for those with 0-9 teeth, compared to those with ≥20 teeth. The OR of incident social isolation was lower for those who used a dental prosthesis [OR = 0.90, 95%CI = 0.80-1.02)] compared to those who did not use a dental prosthesis. The interaction between the number of teeth and dental prosthesis use demonstrated that the latter mitigated the incidence of social isolation for participants with tooth loss. Compared to those with ≥20 teeth (with or without prosthesis use), participants with 0-9 teeth that did not use a dental prosthesis were 79% [OR = 1.79, 95%CI = 1.49-2.19] more likely to be socially isolated, whereas participants with 0-9 teeth that used a dental prosthesis were only 23% [OR = 1.23, 95%CI = 1.05-1.45] more likely to be socially isolated.

CONCLUSION

Tooth loss was the main predictor for social isolation at follow-up, while no dental prostheses use was an additional risk factor. Dental prosthesis use may reduce the risk of social isolation especially in those with severe tooth loss.

Loneliness, Social Isolation, and Living Alone Associations With Mortality Risk in Individuals Living With Cardiovascular Disease: A Systematic Review, Meta-Analysis, and Meta-Regression

OBJECTIVE

This study aimed to conduct a systematic review and meta-analysis of associations between loneliness, social isolation, and living alone and risk of mortality among individuals with established cardiovascular disease.

METHODS

Five electronic databases were searched (MEDLINE [Ovid], PsycINFO, EMBASE, PubMed, and SCOPUS) from inception to November 25, 2021. In all, 35 studies were included in a narrative synthesis and, where appropriate, a meta-analytic evaluation using a random-effects model.

RESULTS

Living alone was associated with increased risk of all-cause mortality ( k = 15, n = 80,243, hazard ratio [HR] = 1.48, 95% confidence interval [CI] = 1.20-1.83, I2 = 83%), and meta-regressions found that the effects were stronger in studies from Europe and with longer follow-up. However, there was evidence of publication bias. Social isolation was associated with increased risk of all-cause mortality, measured both as a dichotomous variable ( k = 3, n = 2648, HR = 1.46, 95% CI = 1.08-2.04, I2 = 31%) and as a continuous variable ( k = 5, n = 2388, HR = 1.11, 95% CI = 1.02-1.24, I2 = 51%). Meta-analysis was not feasible for loneliness as exposure, but narrative synthesis of four studies suggested a tentative association between loneliness and increased risk of all-cause mortality.

CONCLUSIONS

Supporting public health concerns, our review finds that loneliness, social isolation, and living alone are associated with premature mortality among individuals with established cardiovascular disease. However, evidence of publication bias and large methodological differences across studies point to the need for more rigorous research.

Trajectories of Preventive Health Care Utilization Among Older Koreans: The Role of Social Relationships

Background

Receiving timely health screening is associated with important public health benefits among older adults. By focusing on the role of social relationships, the present study was aimed at examining longitudinal trajectories of health screening use among older adults in Korea, whose universal health care system provides free-of-charge health screening.

Methods

A nationally representative sample of 3,575 individuals aged 65 or older from wave one of the Korean Longitudinal Study of Aging (2006) was followed for 10 years (up to Wave 6, 2016). Mixed-effect logit models were used to investigate how an older adult’s social relationship characteristics (i.e., household composition, financial support from family, social group participation, and the frequency of contact with friends or relatives) were associated with their trajectories of participation in the national health screening program.

Results

Despite the low financial burden, only 49.7% of older adults in Korea reported receiving the recommended health screening at the baseline. Although the probability of receiving recommended health screening increased over the 10-year study period, the trajectories were significantly different by an older adult’s social relationship characteristics. All four social relationship characteristics were significantly associated with receiving health screening. However, those with more frequent social contacts and those who participated in social groups showed steeper increases in the probability of receiving health screening (i.e., significant interaction with time).

Conclusions

This study highlights the importance of social relationships and intervention approaches that accommodate socially isolated older adults to facilitate their timely receipt of recommended preventive care.

Cognitive decline and poor social relationship in older adults during COVID-19 pandemic: can information and communications technology (ICT) use helps?

Background

To answer whether older adults' cognitive function benefits from ICT use, we (1) examined the relationship between ICT use and cognitive decline during the COVID-19 pandemic and (2) explored the potential role of ICT use in mitigating the relationship between loneliness, social isolation, and cognitive decline among community-dwelling older adults.

Methods

From February to March 2021, a mail survey was distributed to 1,400 older adults aged 70–89 years old. Responded participants were 1,003 (71.6% response rate). Subjective cognitive decline (SCD) was the independent variable. ICT use was assessed based on ICT use history and current ICT use activities. Loneliness was based on the Japanese version of the Three-Item Loneliness Scale. Social isolation was a total score of six items. Covariate-adjusted logistic regressions were performed and stratified by age groups (70–79 and ≥ 80 years).

Results

During the COVID-19 epidemic, the proportion of people aged ≥ 80 years who reported cognitive decline was twice that of 70s. Non-ICT use was independently associated with a higher risk of cognitive decline in participants aged ≥ 80 years. Furthermore, the significant associations between cognitive decline and interaction items (non-ICT use by loneliness or social isolation) were observed in the ≥ 80 age group. No association was found in the 70–79 age group.

Conclusions

Non-ICT users with high loneliness or social isolation scores were more likely to experience cognitive decline for adults age ≥ 80 years. For older adults who were vulnerable to poor social relationships, ICT use is potentially an efficient intervention. Further longitudinal investigations are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03061-z.

Relationship of smoking with current and future social isolation and loneliness: 12-year follow-up of older adults in England

BACKGROUND

Smoking is often colloquially considered "social". However, the actual relationship of smoking with current and future social isolation and loneliness is unclear. We therefore examined these relationships over a 12-year follow-up.

METHODS

In this cohort study, we used a nationally representative sample of community dwelling adults aged 50 years and over from the English Longitudinal Study of Ageing (N=8780) (45% male, mean(SD) age 67(10) years. We examined associations of self-reported smoking status at baseline assessment, with social isolation (low social contact, social disengagement, domestic isolation), and loneliness (3-item UCLA loneliness scale), measured at baseline, and follow-up at 4, 8 and 12 years, using ordinary least squares regression models.

FINDINGS

At baseline, smokers were more likely to be lonely (coef.=0·111, 95% CI 0·025 - 0·196) and socially isolated than non-smokers, having less frequent social interactions with family and friends (coef.= 0·297, 95%CI 0·148 - 0·446), less frequent engagement with community and cultural activities (coef.= 0·534, 95%CI 0·421 - 0·654), and being more likely to live alone (Odds Ratio =1·400, 95%CI 1·209 - 1·618). Smoking at baseline was associated with larger reductions in social contact (coef.=0·205, 95%CI 0·053 - 0·356, to 0·297, 95%CI 0·140 - 0·455), increases in social disengagement (coef.=0·168, 95%CI 0·066 - 0·270, to coef.=0·197, 95%CI 0·087 - 0·307), and increases in loneliness (coef.=0·105, 95%CI 0·003 - 0·207), at 4-year follow-up) over time. No association was found between smoking and changes in cohabitation status. Findings were independent of all identified confounders, including age, sex, social class and the presence of physical and mental health diagnoses.

INTERPRETATION

Smoking is associated with the development of increasing social isolation and loneliness in older adults, suggesting smoking is detrimental to aspects of psychosocial health. The idea that smoking might be prosocial appears a misconception.

FUNDING

UK Economic and Social Research Council & Imperial College London.

Increase in Social Isolation during the COVID-19 Pandemic and Its Association with Mental Health: Findings from the JACSIS 2020 Study

The coronavirus disease 2019 (COVID-19) pandemic is assumed to have caused an increase in the number of socially isolated people. However, the prevalence of social isolation during the pandemic has not been well studied, particularly among Asian populations. This study investigated changes in the prevalence of social isolation caused by the COVID-19 pandemic and examined its association with mental health among the general Japanese population. Data were obtained from a large-scale, web-based nationwide survey conducted from August to September 2020 (n = 28,000; aged 15–79 years). Social isolation was defined as less frequent contact with people other than co-residing family members. We assessed the participants’ frequency of contact in January (before the pandemic) and August 2020 (during the pandemic). Mental health outcomes included psychological distress, suicidal ideation, loneliness, and fear of COVID-19. We analyzed the data of 25,482 respondents. The weighted prevalence (95% confidence interval) of social isolation was 21.2% (20.7–21.7%) and 27.9% (27.3–28.4%) before and during the pandemic, respectively. The prevalence of social isolation increased by 6.7 (6.3–7.0) percentage points during the pandemic. Older people and men had the greatest increase in the prevalence of social isolation. People who became socially isolated during the pandemic had greater loneliness and fear of COVID-19 than those who were consistently not socially isolated since before the pandemic. This study suggested that social isolation had increased during the COVID-19 pandemic in Japan. Our findings highlight the importance of developing immediate measures against social isolation to maintain good mental health.

Examining the associations between oral health and social isolation: A cross-national comparative study between Japan and England

In Western countries, the most important part of the face in communication is the mouth, whereas it is the eyes in Asian countries; thus oral health could be more important in social interactions in Western countries. Our aim was to examine differences in the association between oral health status and social isolation among older people by comparing Japan and England. We used cross-sectional information obtained from adults aged 65+ in two ongoing prospective cohort studies: The Japan Gerontological Evaluation Study (JAGES, N = 120,195) and the English Longitudinal Study of Ageing (ELSA, N = 3,958). The dependent variable, social isolation score (SIS) was calculated from five factors (marital status, social support from children, social support from family, social support from friends, and social participation). The independent variables were self-reported number of remaining teeth (0, 1-9, 10-19, ≥20) and denture use (≥20 teeth, 10-19 teeth with denture, 10-19 teeth without denture, 0-9 teeth with denture, 0-9 teeth without denture), while the covariates in the model were: sex, age, educational attainment, self-rated health, number of comorbidities, household annual equivalized income, mental health status, daily living activities, and smoking status. We examined associations between oral health status and SIS by applying an ordered logit model by country. Compared to England, more Japanese participants were socially isolated (1.4% vs. 5.8%), but fewer were edentulous (13.1% vs. 7.7%). In both countries, poorer oral health further increased the odds of being socially isolated. Pooled analysis of the ordered logit model with an interaction term showed that the association of number of remaining teeth with SIS was stronger in edentulous participants and in England (odds ratio = 1.50, 95% Confidence interval:1.26-1.80). In both countries, oral health was associated with social isolation; this association could be stronger in England than in Japan.

Association between social isolation and depression onset among older adults: a cross-national longitudinal study in England and Japan

OBJECTIVE

Social isolation is a risk factor for depression in older age. However, little is known regarding whether its impact varies depending on country-specific cultural contexts regarding social relationships. The present study examined the association of social isolation with depression onset among older adults in England, which has taken advanced measures against social isolation, and Japan, a super-aged society with a rapidly increasing number of socially isolated people.

DESIGN

Prospective longitudinal study.

SETTING

We used data from two ongoing studies: the English Longitudinal Study of Ageing (ELSA) and the Japan Gerontological Evaluation Study (JAGES).

PARTICIPANTS

Older adults aged ≥65 years without depression at baseline were followed up regarding depression onset for 2 years (2010/2011-2012/2013) for the ELSA and 2.5 years (2010/2011-2013) for the JAGES.

PRIMARY OUTCOME MEASURE

Depression was assessed with eight items from the Centre for Epidemiologic Studies Depression Scale for the ELSA and Geriatric Depression Scale for the JAGES. Multivariable logistic regression analysis was performed to evaluate social isolation using multiple parameters (marital status; interaction with children, relatives and friends; and social participation).

RESULTS

The data of 3331 respondents from the ELSA and 33 127 from the JAGES were analysed. Multivariable logistic regression analysis demonstrated that social isolation was significantly associated with depression onset in both countries. In the ELSA, poor interaction with children was marginally associated with depression onset, while in the JAGES, poor interaction with children and no social participation significantly affected depression onset.

CONCLUSIONS

Despite variations in cultural background, social isolation was associated with depression onset in both England and Japan. Addressing social isolation to safeguard older adults' mental health must be globally prioritised.

Social isolation enhances cued-reinstatement of sucrose and nicotine seeking, but this is reversed by a return to social housing

Physical or perceived (i.e. loneliness) social isolation is increasing in Western cultures. Unfortunately, social isolation is associated with a range of negative physical and mental health outcomes, including increased incidence of obesity and smoking. Here we monitored the impact of social isolation on a range of physical measures, and then tested whether social isolation in adult rats changes how reward-related stimuli motivate sucrose- or nicotine-seeking. Socially isolated rats showed elevated baseline CORT, gained significantly less weight across the study, were more active in response to a novel or familiar environment. Isolated rats also acquired nose-poking for a food pellet more rapidly, and showed increased susceptibility to cue-, but not reward-induced reinstatement. Notably, these effects are partially mitigated by a return to group housing, suggesting that they are not necessarily permanent, and that a return to a social setting can quickly reverse any deficits or changes associated with social isolation. This study advances our understanding of altered reward-processing in socially isolated individuals and reiterates the importance of socialisation in the treatment of disorders such as overeating and addiction.