Open Access Research article

Relationship between tooth loss and mortality in 80-year-old Japanese community-dwelling subjects

Toshihiro Ansai1*, Yutaka Takata2, Inho Soh1, Shuji Awano1, Akihiro Yoshida1, Kazuo Sonoki2, Tomoko Hamasaki3, Takehiro Torisu2, Akira Sogame4, Naoko Shimada5 and Tadamichi Takehara1

Author Affiliations

1 Division of Community Oral Health Science, Department of Health Promotion, Kyushu Dental College, Kitakyushu, Japan

2 Division of General Internal Medicine, Department of Health Promotion, Kyushu Dental College, Kitakyushu, Japan

3 Division of Nutrition, Department of Home Economics, Kyushu Women's University, Kitakyushu, Japan

4 Kurate Office for Health, Human Services and Environmental Issues, Nogata, Japan

5 Kitakyushu Public Health and Welfare Bureau, Kyushu Dental College, Kitakyushu, Japan

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BMC Public Health 2010, 10:386  doi:10.1186/1471-2458-10-386

Published: 1 July 2010



Findings from several studies suggest associations between tooth loss and health outcomes, including malnutrition, poor quality of life, and mortality, in older individuals. However, limited information is available regarding whether those associations remain true in very elderly subjects after adequately considering confounding factors such as sex and smoking status. Herein, we determined whether the number of teeth in 80-year-old subjects is an independent predictor of mortality.


We initially contacted 1282 80-year-old community-dwelling individuals born in 1917, of whom 697 responded and participated in a baseline study, with follow-up examinations conducted 4 and 5.5 years later. Data from interviews and medical and oral examinations were obtained, and oral health was determined according to the number of teeth remaining in the oral cavity.


A total of 108 and 157 subjects died in 4 years and 5.5 years, respectively, after the baseline study. Tooth loss was significantly associated with mortality at age 85.5, but not at age 84, after adjusting for potential confounders. When the analysis was stratified by sex, we found a stronger association in females in follow-up examinations conducted at both 4- and 5.5 years. On the other hand, the effect of tooth loss on mortality was not significantly different between smokers and non-smokers.


Tooth loss is a significant predictor of mortality independent of health factors, socio-economic status, and lifestyle in octogenarians, with a stronger association in females.