Persistent impact of housing loss on cognitive decline after the 2011 Great East Japan earthquake and tsunami: Evidence from a 6-year longitudinal study

Natural disaster-induced dementia and cognitive decline: A meta-analysis and systematic review

Recently, some studies have noted a negative cognitive impact on individuals in the aftermath of large-scale natural disasters; however, the causal relationship between disasters and cognitive/neurodegenerative effects remains widely unexplored. This review analyzes the impact of natural disasters on the development of cognitive decline (CD), all-cause dementia, and Alzheimer's disease (AD) in disaster-affected individuals. Studies reported from their inception to August 2023 were obtained via public online databases. All data presented in this review was derived from precalculated study results, data presented within/alongside articles, or statistics calculated using data obtained by contacting the articles' authors for ancillary information. Data from 28 studies, representing 4,606,561 individuals, 158,994 CD events, 179,694 dementia events, and 47,193 AD events was included for analysis. The pooled odds ratio (OR) and 95% confidence interval (CI) estimates showed that natural disasters significantly increased the risk of CD (OR: 1.25, CI: 1.20-1.30), all-cause dementia (OR: 1.07, CI: 1.05-1.08), and AD (OR: 1.07, CI: 1.05-1.10) in disaster victims as opposed to less- or non-impacted individuals. The greatest effects were noted following hurricanes, earthquakes with tsunamis, and heat waves. The findings from this meta-analysis indicate that natural disasters are significantly associated with the development of CD, all-cause dementia, and AD.

Effects of volcanic eruptions on the mental health of exposed populations: a systematic review

Introduction

Millions of people living in volcanic environments are at risk of experiencing volcanic eruptions, a natural disaster. This systematic review aimed to collect empirical evidence of the effects of volcanic eruptions on the mental health of the exposed populations.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted systematic searches on Scopus, PubMed, PsycINFO, Medline, and Web of Science (WoS) databases.

Results

A total of 17,044 articles were screened. Of these, 24 articles met the inclusion criteria and data were extracted. Twenty-one articles investigated psychological disorders, two articles studied emotions and their relationships with certain environmental factors, and one article explored cognitive functions in the exposed populations. These studies showed that highly exposed populations were more vulnerable to develop long-lasting psychological disorders than less exposed populations.

Conclusion

The negative influence of experiencing volcanic activity on mental health was confirmed. Clearly, there is a need for more research to improve the mental health of the populations highly exposed to volcanic eruptions. Recommendations for future research are also included.

Long-Term Trajectories of Cognitive Disability Among Older Adults Following a Major Disaster

Importance

Older adults are at high risk for cognitive impairments following natural disasters, but the persistence of such effects is not well understood.

Objective

To track older adults' postdisaster cognitive disability trajectories over a decade and examine associations of cognitive disability with disaster damage exposure.

Design, Setting, and Participants

This prospective cohort study used predisaster baseline surveys conducted in August 2010 and 4 follow-ups approximately every 3 years until November 10, 2022. Invitations were mailed at baseline to all citizens 65 years or older in Iwanuma City, Japan, a coastal municipality significantly impacted by the 2011 Great East Japan Earthquake and Tsunami. A total of 1988 respondents who were cognitively independent (ie, without cognitive disability) before the disaster completed the 4 postdisaster cognitive assessments.

Exposures

Experiences of residential damage, worsening financial conditions, loss of loved ones, and disruption in health care services. A composite score quantified these experiences, with higher scores indicating greater overall damage.

Main Outcomes and Measures

Cognitive disability level was assessed using a standardized in-home evaluation under a national long-term care insurance scheme. Trained investigators evaluated participants' activities of daily living, cognitive function, and presence of mental and/or behavioral disorders. Latent class growth analyses (LCGA) identified distinct cognitive disability trajectories. Primary outcomes consisted of inclusion in these trajectories.

Results

The analytic sample consisted of 1988 participants who were cognitively independent at baseline, with a mean (SD) age of 72.4 (5.4) years, of whom 1159 (58.3%) were female. LCGA identified 3 cognitive disability trajectories: high and gradual deterioration (277 [13.9%]; high levels of cognitive disability with increasing impairment over time), low and progressive deterioration (541 [27.2%]; low levels of cognitive disability with accelerated decline in cognitive function over time), and low and stable (1170 [58.9%]; low levels of cognitive disability that remained stable). In multinomial regression analyses with the low and stable trajectory serving as the reference, housing damage (adjusted odds ratio [AOR], 2.52; 95% CI, 1.26-5.04), worsening financial conditions (AOR, 1.83; 95% CI, 1.15-2.90), and disruption in health care services (AOR, 1.76; 95% CI, 1.03-2.99) were associated with high and gradual deterioration. Worsening financial conditions (AOR, 1.38; 95% CI, 1.01-1.90) and higher composite damage scores (AOR, 1.16; 95% CI, 1.01-1.34) were associated with low and progressive deterioration. These associations no longer remained after adjusting for postdisaster depressive symptoms.

Conclusions and Relevance

In this cohort study of older adults who survived the 2011 Great East Japan Earthquake and Tsunami, disaster-related exposures were associated with worse long-term cognitive disability trajectories. These findings could inform tailored interventions to preserve cognitive function in older disaster survivors.

Associations between housing and psychological damage by earthquake and modifiable risk factors for dementia in general older adults: Tohoku Medical Megabank community-based cohort study

AIM

To evaluate the association between housing and psychological damage caused by the Great East Japan Earthquake (GEJE) and modifiable risk factors (MRFs) of dementia for general population of older adults.

METHODS

This cross-sectional study enrolled 29 039 community-dwelling older adults (mean age 69.1 ± 2.9 years, 55.5% women). We evaluated disaster-related damage (by complete or not complete housing damage) and psychological damage (by post-traumatic stress reaction [PTSR]) after the GEJE using a self-report questionnaire. MRFs encompassed the presence of depression, social isolation, physical inactivity, smoking, and diabetes. We examined the association between disaster-related damage and MRFs using ordinary least squares and modified Poisson regression models adjusted for sociodemographic and health status variables.

RESULTS

Complete housing damage and PTSR were identified in 2704 (10.0%) and 855 (3.2%) individuals, respectively. The number of MRFs was significantly larger for the individuals with complete housing damage (β = 0.23; 95% confidence interval [CI]: 0.19-0.27) and PTSR (β = 0.60; 95% CI: 0.53-0.67). Prevalence ratios (PRs) for depression and physical inactivity were higher in individuals with complete housing damage. The PRs for all domains of the MRFs were significantly higher in individuals with PTSR.

CONCLUSIONS

Housing and psychological damage caused by the GEJE were associated with an increased risk factor of dementia. To attenuate the risk of dementia, especially among older victims who have experienced housing and psychological damage after a disaster, multidimensional support across various aspects of MRFs is required. Geriatr Gerontol Int 2024; 24: 509-516.

Do Adverse Childhood Experiences Modify the Association Between Disaster-Related Trauma and Cognitive Disability?

Identifying subpopulations that are particularly vulnerable to long-term adverse health consequences of disaster-related trauma is needed. We examined whether adverse childhood experiences (ACEs) potentiate the association between disaster-related trauma and subsequent cognitive disability among older adult disaster survivors. Data were from a prospective cohort study of older adults who survived the 2011 Great East Japan Earthquake. The baseline survey pre-dated the disaster by 7 months. We included participants who completed follow-up surveys (2013 and 2016) and did not have a cognitive disability before the disaster (n = 602). Disaster-related traumas (i.e., home loss, loss of friends or pets) and ACEs were retrospectively assessed in 2013. Cognitive disability levels in 2016 were objectively assessed. After adjusting for pre-disaster characteristics using a machine learning-based estimation approach, home loss (0.19, 95% confidence interval (CI): 0.09, 0.28) was, on average, associated with greater cognitive disability. Among individuals with ACEs, home loss was associated with even higher cognitive disability levels (0.64, 95% CI: 0.24, 1.03). Losses of friends (0.18, 95% CI: 0.05, 0.32) and pets (0.13, 95% CI: 0.02, 0.25) were associated with higher cognitive disability levels only among those with ACEs. Our findings suggest that individuals with a history of ACEs may be particularly vulnerable to adverse health consequences related to disasters.

Do disasters exacerbate socioeconomic inequalities in health among older people?

Disasters can exacerbate socioeconomic health disparities because of differential exposure (e.g., socioeconomically disadvantaged groups are more likely to be exposed to disaster-related trauma) and differential vulnerability (disadvantaged groups are more likely to suffer health consequences of exposure to trauma). We sought to test whether health disparities among older adults widened in the area which was directly affected by the 2011 Great East Japan Earthquake & Tsunami compared to areas which largely escaped tsunami damage. We used data from a cohort of community-dwelling older adults who were directly affected by the 2011 disaster (the Iwanuma Study) and municipalities that were not directly affected (the JAGES parent cohort excluding Iwanuma city). The Iwanuma Study gathered pre-disaster information from participants in 2010 (seven months before the disaster) as well as post-disaster information in 2013, 2016 and 2019 (2.5, 5.5 and 8.5 years after the disaster). Our outcomes were depressive symptoms (GDS) and instrumental activities of daily living (IADL). We examined the pre- versus post-disaster trends in socioeconomic health disparities using the slope index and relative index of inequality. We then conducted a difference-in-difference analysis comparing the pre/post disaster change in health disparities in the "exposed" city (Iwanuma) compared to "control" cities. We found clear pre-disaster socioeconomic inequalities in both GDS and IADL in both the exposed and control cities. However, the magnitude of these inequalities did not change after the disaster on either the absolute or relative scales. The 2011 disaster in northeastern Japan did not exacerbate pre-existing patterns of health inequalities in the older population.

Association between sense of coherence and health and well-being among older survivors of a natural disaster: a prospective outcome-wide study

We examined whether pre-disaster Sense of Coherence (SOC) mitigated the impact of housing damage on health and well-being of older survivors after the 2011 Japan Earthquake and Tsunami. A panel survey was conducted in a city located 80 km west of the epicenter seven months before and three years after the disaster (3594 respondents). Among respondents with lighter property damage, higher SOC was inversely associated with mental distress (coefficient - 0.29, 95% CI (confidence interval) - 0.39, - 0.19, p < .01), unhappiness (coefficient - 0.33, 95% CI - 0.43, - 0.23, p < .01), low expectation of mutual help (coefficient - 0.17, 95% CI - 0.27, - 0.07, p < .01), and weak community attachment (coefficient - 0.20, 95% CI - 0.30, - 0.11, p < .01). Conversely, among those who experienced housing loss, higher SOC was no longer protectively associated with health and well-being. Loss of generalized resistance resources due to serious damage led to difficulties in stress coping.

Uncovering Heterogeneous Associations Between Disaster-Related Trauma and Subsequent Functional Limitations: A Machine-Learning Approach

This study examined heterogeneity in the association between disaster-related home loss and functional limitations of older adults, and identified characteristics of vulnerable subpopulations. Data were from a prospective cohort study of Japanese older survivors of the 2011 Japan Earthquake. Complete home loss was objectively assessed. Outcomes in 2013 (n = 3,350) and 2016 (n = 2,664) included certified physical disability levels, self-reported activities of daily living, and instrumental activities of daily living. We estimated population average associations between home loss and functional limitations via targeted maximum likelihood estimation with SuperLearning and its heterogeneity via the generalized random forest algorithm. We adjusted for 55 characteristics of survivors from the baseline survey conducted 7 months before the disaster. While home loss was consistently associated with increased functional limitations on average, there was evidence of effect heterogeneity for all outcomes. Comparing the most and least vulnerable groups, the most vulnerable group tended to be older, not married, living alone, and not working, with preexisting health problems before the disaster. Individuals who were less educated but had higher income also appeared vulnerable for some outcomes. Our inductive approach for effect heterogeneity using machine learning algorithm uncovered large and complex heterogeneity in postdisaster functional limitations among Japanese older survivors.

Uneven Growth in Social Capital Organizations After Disasters by Pre-Disaster Conditions in the United States 2000-2014

INTRODUCTION

Community-level social capital organizations are critical pre-existing resources that can be leveraged in a disaster.

AIM

The study aimed to test the hypothesis that communities with larger pre-disaster stocks of social capital organizations would maintain pre-disaster levels or experience growth.

METHODOLOGY

An annual panel dataset of counties in the contiguous United States from 2000 to 2014 totaling 46620 county-years, including longitudinal data on disasters and social capital institutions was used to evaluate the effect of disaster on growth of social capital.

RESULTS

When a county experienced more months of disasters, social capital organizations increased a year later. These findings varied based on the baseline level of social capital organizations. For counties experiencing minor disaster impacts, growth in social capital organizations tends to occur in counties with more social capital organizations in 2000; this effect is a countervailing finding to that of major disasters, and effect sizes are larger.

CONCLUSION

Given the growing frequency of smaller-scale disasters and the considerable number of communities that experienced these disasters, the findings suggest that small scale events create the most common and potentially broadest impact opportunity for intervention to lessen disparities in organizational growth.

The role of neighborhood social capital on health and health inequality in rural and urban China

Given the "community lost" vs. "community saved" debate on how neighborhood solidarity changes with urbanization, we compared the rural-urban difference in the association of individuals' neighborhood social capital with health and the interaction effect between neighborhood social capital and income-poverty on health in China, where huge rural-urban disparities existed. Participants were 5014 Chinese adults (≥ 18 years) (rural: 2034; urban: 2980) from the 2012 cross-sectional Chinese General Social Survey. Health outcome was a factor score constructed by three items. Neighborhood social capital was divided into structural (neighborhood network size, frequency of socializing with neighbors, voting in neighborhood committee election, and participation in neighborhood voluntary activities) and cognitive (perceived neighborhood social cohesion) dimensions. Multivariable linear regression models showed positive associations between perceived neighborhood social cohesion and health in rural (β = 0.08, 95% CI: 0.03,0.14) and urban (β = 0.09, 95% CI: 0.05,0.12) areas. Only in rural but not urban areas was a neighborhood network of 10 or more persons (ref.: none) associated with better health (β = 0.25, 95% CI: 0.05,0.46). Interaction analysis showed that only in rural but not urban areas, with the increase of neighborhood network size, the health gap between the income-poor and the non-income-poor decreased generally. Our study suggested that cohesive neighborhoods benefit both rural and urban residents' health. Health interventions to improve neighborhood social cohesion should be designed to cope with the challenge of urbanization. Policymakers should avoid damaging neighborhood social capital when implementing other public policies, especially in rural areas where neighborhood network seems to matter more for health.

The effect of the 2018 Japan Floods on cognitive decline among long-term care insurance users in Japan: a retrospective cohort study

BACKGROUND

The July 2018 Japan Floods caused enormous damage to western Japan. Such disasters can especially impact elderly persons. Research has shown that natural disasters exacerbated a decline in cognitive function, but to date, there have been no studies examining the effects of this disaster on the elderly. The object of this study was to reveal the effect of this disaster in terms of cognitive decline among the elderly.

METHODS

Study participants were certified users of the long-term care insurance (LTCI) system in Hiroshima, Okayama, and Ehime prefectures from May 2018 to June 2018. The observation period was from July 2018 to December 2018. Our primary outcome was cognitive decline after the disaster using a dementia symptomatology assessment. In addition to a crude model, a multivariate Cox proportional hazards model was used to assess the cognitive decline of victims, adjusting for age classification, gender, the level of dementia scale before the disaster occurred, residential environment, whether a participant used facilities shut down after the disaster, and population density. After we confirmed that the interaction term between victims and residential environment was statistically significant, we stratified them for the analysis.

RESULTS

The total number of participants was 264,614. Victims accounted for 1.10% of the total participants (n = 2,908). For the Cox proportional hazards model, the hazard ratio of the victims was 1.18 (95% confidential interval (CI): 1.05-1.32) in the crude model and 1.12 (95% CI: 1.00-1.26) in the adjusted model. After being stratified by residential environment, the hazard ratio of home victims was 1.20 (95% CI: 1.06-1.36) and the hazard ratio of facility victims was 0.89 (95% CI: 0.67-1.17).

CONCLUSIONS

This study showed that elderly living at home during the 2018 Japan Floods were at risk for cognitive decline. Medical providers, care providers, and local governments should establish a system to check on the cognitive function of elderly victims and provide necessary care support.

Heterogeneity in cognitive disability after a major disaster: A natural experiment study

Cognitive disability following traumatic experiences of disaster has been documented; however, little is known about heterogeneity in the association across individuals. In this natural experiment study of approximately 3000 Japanese older adults in an area directly affected by the 2011 Great East Japan Earthquake, the baseline survey was established 7 months before the 2011 earthquake. To inductively identify heterogeneity in postdisaster cognitive disability by predisaster characteristics, we applied a machine learning–based causal inference approach—generalized random forest. We identified strong evidence for heterogeneity in the association between home loss and cognitive disability objectively assessed 2.5 and 5.5 years after the 2011 earthquake. The subgroups with the strongest disaster-dementia associations tended to be from low socioeconomic backgrounds and have predisaster health problems. The study demonstrated that some subpopulations are particularly prone to experience cognitive disability after disasters, which could be overlooked in studies assessing population average associations only.

Persistent mental health impacts of disaster. Five-year follow-up after the 2011 great east Japan earthquake and tsunami: Iwanuma Study

Few studies have tracked the long-term mental health outcomes following major disaster. We sought to document the trajectories of depressive symptoms and post-traumatic stress symptoms (PTSS) in the aftermath of the 2011 Great East Japan earthquake and tsunami. A cohort of community-dwelling older adults were followed for 5.5 years after the disaster at 3 waves (2010, 2013 and 2016). Depressive symptoms were measured by the Geriatric Depression Scale Short Form, while PTSS was assessed by the Screening Questionnaire for Disaster Mental Health. We examined the trajectories of mental illness symptoms based on the probabilities of persistence, recovery, and delayed onset. Among people without pre-disaster depressive symptoms, 13.6% had developed depressive symptoms 2.5 years after the disaster. Of these, half of those had recovered and half had persisted at the 5.5 year follow-up. 11.1% of survivors reported post-traumatic stress symptoms in 2013; of these, 58% recovered by 2016, while 4.8% experienced delayed onset. Job loss was associated with persistent PTSS (OR 2.03; 95%CI 1.01-4.12) while a drop in subjective economic status predicted delayed onset of PTSS (OR 2.13; 1.34-3.39). However, disaster-related experiences were unrelated to the trajectory of depressive symptoms at 5.5 years. The probabilities of remission (58%) and delayed onset (5%) of PTSS are consistent with prior disaster research. The experience of job loss and drop in subjective economic status appeared to exert a lingering influence on the persistence or delayed onset of PTSS. Depressive symptoms after the disaster had remitted in roughly half of the survivors after 5.5 years.

Six-year follow-up study of residential displacement and health outcomes following the 2011 Japan Earthquake and Tsunami

Studies examining the long-term health consequences of residential displacement following large-scale disasters remain sparse. Following the 2011 Japan Earthquake and Tsunami, victims who lost their homes were resettled by two primary means: 1) group relocation to public housing or 2) individual relocation, in which victims moved into public housing by lottery or arranged for their own accommodation. Little is known about how the specific method of residential relocation affects survivors' health. We examined the association between residential relocation and long-term changes in mental and physical well-being. Our baseline assessment predated the disaster by 7 mo. Two follow-up surveys were conducted ∼2.5 y and 5.5 y after the disaster to ascertain the long-term association between housing arrangement and health status. Group relocation was associated with increased body mass index and depressive symptoms at 2.5-y follow-up but was no longer significantly associated with these outcomes at 5.5-y follow-up. Individual relocation at each follow-up survey was associated with lower instrumental activities of daily living as well as higher risk of cognitive impairment. Our findings underscore the potential complexity of long-term outcomes associated with residential displacement, indicating both positive and negative impacts on mental versus physical dimensions of health.

Long-term effects of housing damage on survivors' health in rural China: Evidence from a survey 10 Years after the 2008 Wenchuan earthquake

BACKGROUND

Disaster experiences have long-term health effects. However, less is known about the pathways of the association between disaster experiences and people's long-term health. We aimed to examine the long-term (10-year) effect of housing damage in the 2008 Wenchuan earthquake on survivors' health and to explore the pathways of the long-term effect.

METHODS

We used data from a survey conducted in 2018 in rural areas affected by the 2008 Wenchuan earthquake. The survey collected information on housing damage caused by the earthquake from survivors aged 18 years old or above. Our primary outcome was dichotomous self-rated health in 2018. We considered decreased living standards and debt burden as mediators. To examine the long-term effect of housing damage on health, we performed multivariable binary logistic regression models. We also performed mediation analyses using the "KHB-method".

RESULTS

Compared with no/slight damage, serious damage (odds ratio (OR): 1.50, 95% confidence interval (CI): 1.11,2.04) and collapse (OR: 1.57, 95% CI: 1.13,2.18) were associated with a higher risk of poor health. Decreased living standards and debt burden mediated 8.49% and 4.79%, respectively, of the association between serious damage and poor health and 10.64% and 6.10%, respectively, of the association between collapse and poor health.

CONCLUSION

Housing damage in a natural disaster is a long-term risk for survivors' health. Long-term policies and interventions are necessary to protect and promote the health of survivors who experience housing damage. In addition to house reconstruction assistance, policies and interventions can be designed to promote living standards and financial situations to protect survivors' health.

Long-term Trends in Mental Health Disorders After the 2011 Great East Japan Earthquake and Tsunami

IMPORTANCE

Posttraumatic stress symptoms (PTSS) and depressive symptoms are common among survivors of a major disaster, yet few longitudinal studies have documented their long-term persistence at the community level.

OBJECTIVE

To examine the trajectories of PTSS and depressive symptoms for as long as 5.5 years after the 2011 Great East Japan earthquake and tsunami.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from 2781 participants in 3 waves of the Iwanuma Study (2010, 2013, and 2016), a cohort of community-dwelling older adults (≥65 years in August 2010) in Iwanuma, Japan, who were directly affected by the 2011 disaster. The baseline assessment of mental health predated the disaster by 7 months, and survivors were followed up for 5.5 years after the disaster. Data analysis was performed from October 2019 to February 2020.

EXPOSURES

The March 11, 2011, Great East Japan earthquake and tsunami.

MAIN OUTCOMES AND MEASURES

PTSS were measured by 9 questions on the Screening Questionnaire for Disaster Mental Health, while depressive symptoms were measured by 15 items on the Geriatric Depression Scale short form.

RESULTS

The analytic samples for trajectories of PTSS and depressive symptoms included 2275 and 1735 respondents, respectively. In the study population at baseline, there were slightly more women (1262 of 2275 [55.5%] and 882 of 1735 [50.8%]), and most participants were aged 65 to 74 years (1533 [67.4%] and 1224 [70.5%]) and married (1664 [76.2%] and 1319 [77.7%]). Overall, there was a 13.6% (95% CI, 11.7%-15.6%) incidence of depression among individuals who did not have depression before the disaster, while a further 11.1% (95% CI, 9.8%-12.4%) reported PTSS after the disaster. By 5.5 years of follow-up, approximately half of the survivors with new depressive symptoms in 2013 (85 of 168 [50.6%]) and PTSS (147 of 253 [58.1%]) had recovered. The prevalence of depression in the community remained remarkably stable (between 504 participants [29.0%] and 506 participants [29.2%]) comparing predisaster and postdisaster data.

CONCLUSIONS AND RELEVANCE

In this study, mental illness symptoms persisted for more than 5 years among half of disaster survivors, but the community-wide prevalence of depression remained stable, suggesting that the community itself was resilient.