The Association between Number of Remaining Teeth and Maintenance of Successful Aging in Japanese Older People: A 9-Year Longitudinal Study

The Association between Number of Remaining Teeth and Maintenance of Successful Aging in Japanese Older People: A 9-Year Longitudinal Study

FUMIYA TANJI,^1,2 TAKAMASA KOMIYAMA,³ TAKASHI OHI,³ YOSHINORI HATTORI,³ MAKOTO WATANABE,⁴ YUKAI LU¹ and ICHIRO TSUJI¹

¹Division of Epidemiology, Department of Health Informatics and Public Health, Tohoku University School of Public Health, Graduate School of Medicine, Sendai, Miyagi, Japan
²Faculty of Nursing, Japanese Red Cross Akita College of Nursing, Akita, Akita, Japan
³Division of Aging and Geriatric Dentistry, Department Oral Function and Morphology, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
⁴Institute of Living and Environmental Sciences, Miyagi Gakuin Women's University, Sendai, Miyagi, Japan

With population aging, an increasing attention has been paid to quality of life rather than mere longevity. Now, it is urgently needed to clarify predictors of well-being in later life, i.e., “successful aging (SA).” The aim of this study is to investigate whether the number of remaining teeth impacts on maintenance of SA among Japanese older people. The present study was conducted in Tsurugaya district, a suburban area of Sendai, in northern Japan, and included older people aged ge; 70 years who had met the criteria for SA at a 2003 baseline survey. At the baseline survey, dentists obtained data for the number of remaining teeth. We obtained information about Long-term Care Insurance certification, including the dates of incident functional disability and death between 2003 and 2012. Data pertaining to health-related quality of life (HRQOL) were collected at the 2003 baseline survey and the 2012 follow-up survey. Maintenance of SA was defined in terms of survival, disability-free status and high HRQOL in both 2003 and 2012. Among 450 participants, 108 (24.0%) were considered to have maintained a state of SA. When participants were classified into three groups according to previous studies, in comparison with participants who retained 0-9 teeth, the multivariate prevalence ratios (95% confidence intervals) were 1.39 (0.81-2.36) for those who retained 10-19 teeth and 1.58 (1.002-2.50) for those who retained ge; 20 teeth (p trend = 0.046). The present results suggest that retaining ge; 20 teeth is associated with maintenance of SA among Japanese older people.

Keywords —— Japan; longitudinal study; older people; successful aging; teeth

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Tohoku J. Exp. Med., 2020 252, 245-252.

Correspondence: Ichiro Tsuji, Prof., Ph.D., Division of Epidemiology, Department of Health Informatics and Public Health, Tohoku University School of Public Health, Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.

e-mail: tsuji1@med.tohoku.ac.jp