Takaaki Ikeda

Dr. Takaaki Ikeda

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 March 2021 in BMJ Open
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Journal Article
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TNTaiji Noguchi
Taiji Noguchi
MSMasashige Saito
Masashige Saito
JAJun Aida
Jun Aida
NNNoriko Cable, N
Noriko Cable, N
TTTaishi Tsuji
Taishi Tsuji
Katsunori KondoKatsunori Kondo
Katsunori Kondo
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.

21 January 2019 in International Journal for Equity in Health
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Journal Article
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TITakaaki Ikeda
Takaaki Ikeda
KSKemmyo Sugiyama
Kemmyo Sugiyama
JAJun Aida
Jun Aida
TTToru Tsuboya
Toru Tsuboya
NWNanae Watabiki
Nanae Watabiki
KOKen Osaka
Ken Osaka
Low back pain is an important public health issue across the world. However, it is unclear whether socioeconomic status (SES) is associated with low back pain. This study determines an association between SES and low back pain among older people. We used cross-sectional data derived from the year 2013 across 30 Japanese municipalities. The survey was conducted between October 2013 to December 2013. Functionally independent community-dwelling older adults aged 65 and above (n = 26,037) were eligible for the study. Multilevel Poisson regression analysis with a robust variance estimator was used to examine the association between SES and low back pain. Self-reported low back pain in the past year was used as a dependent variable. Educational attainment, past occupation, equivalized household income, wealth, and subjective economic situation represented SES and were separately analyzed as independent variables, adjusted for covariates including age and sex. The prevalence of low back pain was 63.4%. Overall, lower SES were more likely to suffer from low back pain compared with that for the highest. First, as for the educational attainment, the prevalence ratio (PR) (95% credible interval (CI)) for the lowest level was 1.07 (1.02–1.12). Second, as for the past occupation, the PR (95% CI) for the blue-collared workers compared with professionals was 1.06 (1.01–1.11). Third, as for the equalized household income, the PRs (95% CI) for lower middle and the lowest income levels were 1.08 (1.02–1.13) and 1.16 (1.10–1.23), respectively. Fourth, as for the wealth, the PRs (95% CI) for lower middle and the lowest wealth levels were 1.11 (1.04–1.19) and 1.18 (1.11–1.27), respectively. Fifth, as for the subjective economic situation, the PRs (95% CI) for lower middle and the lowest financial conditions were 1.18 (1.10–1.26) and 1.32 (1.22–1.44), respectively. Significant socioeconomic inequalities were observed in low back pain among older individuals in Japan. Policymakers and clinicians must understand the nature of these inequalities.

1 May 2021 in Social Science & Medicine
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Journal Article
Open access
SKShihoko Koyama
Shihoko Koyama
MSMasashige Saito
Masashige Saito
NNNoriko Cable, N
Noriko Cable, N
TITakaaki Ikeda
Takaaki Ikeda
TTTaishi Tsuji
Taishi Tsuji
JAJun Aida
Jun Aida
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.

21 December 2020 in Geriatrics & Gerontology International
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Journal Article
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MSMasashige Saito
Masashige Saito
JAJun Aida
Jun Aida
NNNoriko Cable, N
Noriko Cable, N
PZPaola Zaninotto
Paola Zaninotto
TITakaaki Ikeda
Takaaki Ikeda
KKKatsunori Kondo
Katsunori Kondo
Aim: Existing evidence links social isolation with poor health. To examine differences in the mortality risk by social isolation, and in socio‐economic correlates of social isolation, we analyzed large‐scale cohort studies in Japan and England.Methods: Participants were drawn from the Japan Gerontological Evaluation Study (JAGES) and the English Longitudinal Study of Ageing (ELSA). We analyzed the 10‐year mortality among 15 313 JAGES participants and 5124 ELSA respondents. Social isolation was measured by two scales, i.e., scoring the frequency of contact with close ties, and a composite measurement of social isolation risk. We calculated the population attributable fraction, and Cox regression models with multiple imputations were used to estimate hazard ratios (HRs) for mortality due to social isolation.Results: The proportion of those with contact frequency of less than once a month was 8.5% in JAGES and 1.3% in ELSA. Males, older people, those with poor self‐rated health, and unmarried people were significantly associated with social isolation in both countries. Both scales showed that social isolation among older adults had a remarkably higher risk for premature death (less frequent contact with others in JAGES: hazard ratio [HR] = 1.18, 95% confidence interval [CI]: 1.05–1.33, in ELSA: HR = 1.27, 95% CI: 0.85–1.89; and high isolation risk score in JAGES: HR = 1.30, 95% CI: 1.12–1.50, in ELSA: HR = 2.05, 95% CI: 1.52–2.73). The population attributable fraction showed less frequent contact with close ties was attributed to about 18 000 premature deaths annually in Japan, in contrast with about 1800 in England.Conclusions: Negative health impacts of social isolation were higher among older Japanese compared with those in England. Geriatr Gerontol Int 2021; 21: 209–214.

30 January 2021 in Applied Research in Quality of Life
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TITakaaki Ikeda
Takaaki Ikeda
AIAtaru Igarashi
Ataru Igarashi
SOSatomi Odani
Satomi Odani
MMMasayasu Murakami
Masayasu Murakami
Takahiro TabuchiTakahiro Tabuchi
Takahiro Tabuchi

1 January 2020 in Social Science & Medicine
Verified
Journal Article
Open access
KSKoryu Sato
Koryu Sato
TITakaaki Ikeda
Takaaki Ikeda
RWRyota watanabe
Ryota watanabe
NKNaoki Kondo
Naoki Kondo
IKIchiro Kawachi
Ichiro Kawachi
KKKatsunori Kondo
Katsunori Kondo
The World Health Organization (WHO) argues that governments can postpone declining capacity of older adults by providing sufficient support. Yet, to our knowledge, no study has focused on the role of local governments for realizing healthy ageing. This study examined the association between the intensity of community-based programs for frailty postponement by long-term care insurers (as municipalities) and the likelihood of frailty. We analyzed repeated cross-sectional data of three waves (2010-11, 2013, and 2016) from the Japan Gerontological Evaluation Study (JAGES). Participants included 375,400 older adults aged 65 years or older (M = 74.1) living in a total of 81 regions covered by insurers in Japan. Frailty was assessed by a governmental standardized index, the Kihon Check List (KCL; a basic function check list in Japanese). Estimations were obtained using a multilevel logistic model with random slopes. We found that every social activity per hundred older people organized by a long-term care insurer was significantly associated with an 11% reduction of the likelihood of frailty (Odds ratio = 0.89; 95% credible interval = 0.81, 0.99). Although the main effect of educational events was not significant, the point estimate was slightly larger for people with lower levels of education than for those with higher education. The results also suggested that insurer-organized social activities could be more beneficial in communities with few opportunities for civic participation. The variation in intensity of community-based programs by long-term care insurers may explain part of a disparity in the likelihood of frailty between municipalities.