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Dentistry and oral medicine
Research
Dental status and incident falls among older Japanese: a prospective cohort study
  1. Tatsuo Yamamoto1,
  2. Katsunori Kondo2,
  3. Jimpei Misawa2,
  4. Hiroshi Hirai3,
  5. Miyo Nakade4,
  6. Jun Aida5,
  7. Naoki Kondo6,
  8. Ichiro Kawachi7,
  9. Yukio Hirata1
  1. 1Division of Sociological Approach in Dentistry, Department of Dental Sociology, Kanagawa Dental College, Yokosuka-shi, Kanagawa, Japan
  2. 2Center for Well-being and Society, Nihon Fukushi University, Nagoya-shi, Aichi, Japan
  3. 3Department of Civil and Environmental Engineering, Faculty of Engineering, Iwate University, Morioka-shi, Iwate, Japan
  4. 4Department of Nutrition, Faculty of Health and Nutrition, Tokaigakuen University, Nagoya-shi, Aichi, Japan
  5. 5Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai-shi, Miyagi, Japan
  6. 6Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo-shi, Yamanashi, Japan
  7. 7Department of Society, Human Development and Health, Harvard School of Public Health, Boston, Massachusetts, USA
  1. Correspondence to Dr Yukio Hirata; hiratay{at}kdcnet.ac.jp

Abstract

Objective To examine if self-reported number of teeth, denture use and chewing ability are associated with incident falls.

Design Longitudinal cohort study (the Aichi Gerontological Evaluation Study).

Setting 5 Japanese municipalities.

Participants 1763 community-dwelling individuals aged 65 years and older without experience of falls within the previous year at baseline.

Main outcome measures Self-reported history of multiple falls during the past year at the follow-up survey about 3 years later. Baseline data on the number of teeth present and/or denture use and chewing ability were collected using self-administered questionnaires. Logistic regression analyses controlled for sex, age, functional disability during follow-up period, depression, self-rated health and educational attainment.

Results 86 (4.9%) subjects reported falls at the follow-up survey. Logistic regression models fully adjusted for all covariates showed that subjects having 19 or fewer teeth but not using dentures had a significantly increased risk for incident falls (OR 2.50, 95% CI 1.21 to 5.17, p=0.013) compared with those having 20 or more teeth. Among subjects with 19 or fewer teeth, their risk of falls was not significantly elevated so long as they wore dentures (OR 1.36, 95% CI 0.76 to 2.45, p=0.299). No significant association was observed between chewing ability and incident falls in the fully adjusted model.

Conclusions Having 19 or fewer teeth but not using dentures was associated with higher risk for the incident falls in older Japanese even after adjustment for multiple covariates. Dental care to prevent tooth loss and denture treatment for older people might prevent falls, although the authors cannot exclude the possibility that the association is due to residual confounding.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.

https://doi.org/10.1136/bmjopen-2012-001262

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    Footnotes

    • To cite: Yamamoto T, Kondo K, Misawa J, et al. Dental status and incident falls among older Japanese: a prospective cohort study. BMJ Open 2012;2:e001262. doi:10.1136/bmjopen-2012-001262

    • Contributors TY and YH had the idea for the study, participated in its design, performed the statistical analysis and drafted the manuscript, and YH is the guarantor. KK is coordinator of Aichi Gerontological Evaluation Study Project, helped develop the idea of the study, participated in acquiring the data and with design and edited the manuscript. JM participated in design of study and edited the manuscript. HH and MN participated in acquiring the data and with design and critically revised the manuscript. JA, NK and IK participated in the design of the study, deciding on statistical methods used, helped in interpreting the results and revising the manuscript.

    • Funding This study was supported in part by a grant of the Strategic Research Foundation Grant-aided Project for Private Universities from Ministry of Education, Culture, Sport, Science and Technology, Japan (MEXT), 2009–2013, and Health Labour Sciences Research Grant, Comprehensive Research on Aging and Health (H22-Choju-Shitei-008) from the Japanese Ministry of Health, Labour and Welfare.

    • Competing interests None.

    • Ethical approval The Aichi Gerontological Evaluation Study protocol including the present study was reviewed and approved by the Ethics Committee on Research of Human Subjects at Nihon Fukushi University.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data sharing statement No additional data available.