Published papers

In the context of global population ageing and concentration in cities, the population aged 80 and over (80+) is growing rapidly. Japan has the fastest ageing population and longest healthy average life expectancy, while health decline becomes pronounced and care needs increase in the 85+ age group post the ‘average life expectancy’. The healthy ageing of older urban community dwellers is a pressing issue in world initiatives for sustainable urbanisation. However, for the 85+ age group, less is known about how promoting/inhibiting factors and their pathways influence healthy ageing, and related longitudinal studies remain insufficient. Using data from a longitudinal cohort study conducted from 2008–2009 to 2014–2015 among independent dwellers aged 85+ in central Tokyo (men = 203, women = 232), this study analysed the impact pathways of environmental, social, and behavioural factors on health and survival to explore promoters and potential risks on healthy ageing by gender, with multi-group structural equation modelling (SEM) and Bayesian SEM. For both genders, there was a positive chained pathway starting from friends as facilitators through positive interactions between 'social participation’ and 'active behaviour' to 'ageing-related health'. Additionally, their personal networks were small, suggesting that men with family-centred networks and women with non-family-centred networks require different approaches and supports. Implications of the results are discussed, and an organised social watch and support system, which becomes more important in the ‘new normal’ for urban dwellers aged 85+, is recommended.

Gerotranscendence is associated with the physical and psychological well-being of older adults. However, findings regarding the changes in gerotranscendence based on age are inconsistent. Therefore older adults in Japan. A total of 3,011 older adults were included in this study. The total Japanese Gerotranscendence Scale Revised scores were measured in one to four surveys every 3–4 years. A linear mixed-effects, this study aimed to examine age-related changes in gerotranscendence at four time points over a 9-year period in community-dwelling model analysis was used to test the following hypotheses: 1. gerotranscendence increases with age; 2. the magnitude of increase in gerotranscendence differs by gender and age group and these effects remain significant even after adjusting for control variables. Results from the mixed-effects model showed that controlling for the number of years of education, absence of cohabitants, self-rated health, instrumental activities of daily living, and psychological well-being, average gerotranscendence increased over time. At baseline, women and older age groups reported significantly higher levels of gerotranscendence. The magnitude of the temporal change in gerotranscendence was shown to be age-related. In other words, the increase in gerotranscendence plateaued at higher old ages. Gerotranscendence is a valuable psychological function that increase during old age—associated with a decline in physical and cognitive functioning.

Objective: To clarify the relationship between life satisfaction and the psychological characteristics of the oldest-old, and explore the factors for achieving mental health and longevity. Design: This cross-sectional study conducted questionnaire surveys and face-to-face interviews as part of a larger prospective cohort study. Setting: Arakawa Ward, a district in Tokyo, Japan. Participants: A total of 247 oldest-old individuals from two age groups, 85+ (aged 85–87 years) and 95+ (aged 95 years or older). Measurements: Life satisfaction was assessed using the Satisfaction with Life Scale (SWLS), developmental stages of the elderly (Erikson's 8th and 9th stages, i.e., ego integrity, and gerotranscendence), and the Big Five personality traits (extraversion, agreeableness, openness, conscientiousness, and neuroticism) using the NEO-Five Factor Inventory. Multiple regression analyses were performed to examine the relationship between the SWLS scores and each assessment, controlling for age, sex, education, activities of daily living, depressive symptoms, and cognitive function. Results: The SWLS scores of 85+ were positively correlated with scores of ego integrity, extraversion, and conscientiousness. Contrastingly, the SWLS scores of 95+ were positively correlated with gerotranscendence scores. Conclusions: Psychological characteristics associated with the level of life satisfaction among community-dwelling oldest-old individuals were identified, but a causal relationship between these factors and life satisfaction was not established. Ego integrity, extraversion, conscientiousness, and gerotranscendence may be associated with enhanced life satisfaction and mental health in the oldest-old. Further, the factors associated with life satisfaction in the 85+ and 95+ age groups varied, suggesting that life satisfaction among the oldest-old has different foundations in different age groups.

平均余命の伸長が著しいなか，高齢期の心理的発達をとらえる理論的枠組みが求められている．本研究は，その発達過程を探索するため，心理的発達を遂げている超高齢者を対象に，彼らが日常生活で体験していることを記述することを目的とした．超高齢者8人を対象に面接調査を実施し，解釈的現象学の視点から質的分析を行った．超高齢者の語りのうち，生命，生活，人生という生（life）の諸側面に対する意味や価値に焦点を当て，意味ある単位に分類した結果，「つながっていること」「変わっていくことに気づくこと」「変わらないことを見いだすこと」「自分だけにできることをみつけること」の4つのテーマを抽出した．この結果から，超高齢者の生の体験は，客観的な事実から成る状況に身をおきつつ，二元的思考を脱する実存的な体験としてとらえることができるであろう．今後，かかる超高齢者における生の実存的側面をとらえるために，超越の視点が必要であると考えられる．

To investigate various risk factors of cognitive decline in the very old, we studied 494 subjects over 85 years old without diagnosis of dementia at baseline from the Tokyo Oldest Old Survey on Total Health, an ongoing, community-based cohort in Japan. Cognitive function was assessed at baseline and at 3-year follow-up using Mini-Mental State Examination (MMSE). Plasma samples were assayed for levels of cytomegalovirus (CMV) immunoglobulin G (IgG) antibodies, tumor necrosis factor-alpha, interleukin-6, and blood chemistry. Carotid artery plaques were measured using an ultrasonography. In the cross-sectional analyses using Tobit regression, individuals with high carotid artery plaque score (≥5.0) had MMSE scores that were 1.08 points lower compared to those with no plaque (95 % confidence interval (CI) −1.95 to −0.20; p = 0.016), adjusted for age, sex, and education. Individuals with CMV IgG titers in the highest quartile had MMSE scores that were 1.47 points lower compared to individuals in the lowest quartile (95 % CI −2.44 to −0.50; p = 0.003). CMV and carotid atherosclerosis showed evidence of an interaction, where the association between CMV and MMSE was present only in subjects with carotid artery plaque. In the longitudinal analyses using linear regression, carotid atherosclerosis, smoking, low grip strength, and poor activities of daily living (ADL) status were associated with faster cognitive decline, adjusted for age, sex, education, and baseline cognitive function. Our findings suggest that carotid atherosclerosis is consistently associated with low cognitive function in the very old and modifies the association between latent CMV infection and cognition.

Aim: Few cohort studies targeting the oldest-old individuals have been carried out. The subiculum in the hippocampus is thought to be related to memory function, and atrophy of this structure might result in the conversion from amnestic mild cognitive impairment to Alzheimer's disease. Thus, we sought to examine the relationship between subiculum volumes and memory function in individuals aged ≥95 years, using a novel cognitive examination called the Addenbrooke's Cognitive Examination III (ACE-III) and an advanced magnetic resonance imaging analytical method, Multiple Automatically Generated Templates Brain Segmentation Algorithm (MAGeTbrain), to measure hippocampal subfield volumes. Methods: A part of the cohort data of the Arakawa 95+ study for the oldest-old aged ≥95 years was used. A total of 10 individuals completed all of the examinations. The MAGeT brain was applied to estimate the subfield volumes of the hippocampus. Correlation analyses and multiple regression analyses were carried out to examine a relationship among ACE-III memory scores and the subfield volumes in the hippocampus, including the subiculum. Results: There was a significant relationship between ACE-III memory scores and subdivision volumes. Regression analyses showed that subiculum volumes were associated with ACE-III memory scores in the oldest-old individuals (β = 0.721, P = 0.019; F = 8.67, adjusted R = 0.46). Conclusions: The subiculum might play a pivotal role in memory function in the oldest-old individuals aged ≥95 years. The present finding warrants further research including larger sample sizes. Geriatr Gerontol Int 2019; 19: 347–351. 1, 8 2

Aim: The aim of this study was to examine sociopsychological characteristics of the oldest old in Japan. We conducted a baseline survey of a community-based cohort of persons aged 95 or older. Methods: Participants were aged 95+ years and resided in Arakawa Ward in Tokyo on 1 January 2016. We mailed a questionnaire to these individuals to assess their physical, mental, and social status. Subsequently, if respondents agreed, we conducted in-home interviews and examined their physical and cognitive function. Also, we mailed non-respondents a simplified version of full questionnaire. Additionally, we examined the basic registered data of the study population and the status of their Long-term Care Insurance. Data at baseline and 1-year follow-up were compared. Results: With regard to Long-term Care Insurance, 423 residents aged 95+ years (78.0%) were on long-term care level, 35 (6.5%) were on support level, and 84 (15.5%) did not require support. At the 1-year follow-up, 275 (50.7%) had the same care level, 107 (19.7%) required a greater level of care, and 131 had died (annual death rate: 24.2%). Compared to the simplified questionnaire group (n = 128) and the full questionnaire-only group (n = 14), a higher proportion of respondents who had completed the full questionnaire and had in-home interviews (n = 26) were men, lived only with a spouse, had higher activities of daily living, and reported more positive feelings and well-being. Conclusions: In the late nonagenarian population, the annual death rate was high, and care needs increased rapidly. However, some persons maintained the same care level or even showed improvement and successful ageing.