Does social capital affect the incidence of functional disability in older Japanese? A prospective population-based cohort study
- Jun Aida1,2,
- Katsunori Kondo3,
- Ichiro Kawachi4,
- S V Subramanian4,
- Yukinobu Ichida3,
- Hiroshi Hirai3,5,
- Naoki Kondo6,
- Ken Osaka1,
- Aubrey Sheiham2,
- Georgios Tsakos2,
- Richard G Watt2
- 1Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan
- 2Department of Epidemiology and Public Health, University College London, London, UK
- 3Center for Well-being and Society, Nihon Fukushi University, Nagoya, Japan
- 4Department of Society, Human Development and Health, Harvard School of Public Health, Boston, Massachusetts, USA
- 5Department of Civil Environmental Engineering, Iwate University, Iwate, Japan
- 6Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo-shi, Japan
- Correspondence to Dr Jun Aida, Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan;
Contributors JA had the idea for the study, participated in its design, performed the statistical analysis and drafted the manuscript as a principal author. KK helped develop the idea of the study, participated in acquiring the data and with design and edited the manuscript. IK participated in design of study and edited the manuscript. SVS participated in design of study, helped statistical analyses and critically revising the manuscript. YI and HH participated in acquiring the data, helped statistical analyses and critically revising the manuscript. NK participated in designing study and critically revising the manuscript. KO helped with the data analysis and critically revised the manuscript. AS, GT and RGW participated in design of study and helped to write and revise the manuscript. All authors read and approved the final manuscript.
- Accepted 30 May 2012
- Published Online First 3 July 2012
Background Recent increases in numbers of older people have been accompanied by increases in those with functional disability. No study has examined the association between community social capital and the onset of functional disability.
Methods The association between community social capital and the onset of functional disability was examined using data from the Aichi Gerontological Evaluation Study, a prospective cohort established in 2003 in Japan. Perceptions of community social capital (indicators of social cohesion such as trust of others and extent of social participation) in 6953 men and 7636 women aged 65 years or older were surveyed. Multilevel survival analysis using the discrete-time hazard model was applied.
Results During 4-year follow-up, onset of functional disability occurred in 759 men and 1146 women. Women living in communities with higher mistrust had 1.68 (95% CI 1.14 to 2.49) times higher OR of onset of disability, even after adjusting for covariates. Mediators did not substantially change this association. Lack of social participation seemed to affect the health of women, though the effect was marginal (OR for covariates adjusted model =1.12 (95% CI 0.96 to 1.31)). There were no significant ORs among men.
Conclusions Lower community social capital was associated with higher incidence of onset of functional disability among older women but not among men. Community-based interventions to promote social capital may be useful for preventing functional disability of older Japanese women.
- Social epidemiology
- dental health
- public health
- social inequalities
- multilevel modelling
Funding This study was partially supported by a grant of Strategic Research Foundation Grant-aided Project for Private Universities from Ministry of Education, Culture, Sports, Science and Technology, Japan, 2009–2013, and Grant-in-Aid for Scientific Research (B) (22390400) and (C) (22592327) from the Japan Society for the Promotion of Science. The sponsors of the study had no role in the study design, data collection, data analysis, data interpretation or writing of the paper.
Competing interests None.
Ethics approval The ethics approval was provided by the ethics committee on Research of Human Subjects at Nihon Fukushi University.
Provenance and peer review Not commissioned; externally peer reviewed.