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, 13 (4), e0195813

Tooth Loss and Pneumonia Mortality: A Cohort Study of Japanese Dentists


Tooth Loss and Pneumonia Mortality: A Cohort Study of Japanese Dentists

Shino Suma et al. PLoS One.


Although associations between oral health and pneumonia have been reported in previous studies, particularly in the institutionalized elderly, few prospective studies have investigated the association between oral condition and pneumonia among community-dwelling people and whether the findings among inpatients or patients in nursing homes are applicable to the general population is still unclear. The oral bacteria propagated in the periodontal regions may drop into the lung and increase the risk of pneumonia. We, therefore, investigated the association of tooth loss with mortality from pneumonia in a cohort study of Japanese dentists. Members of the Japan Dental Association (JDA) participated in the LEMONADE (Longitudinal Evaluation of Multi-phasic, Odontological and Nutritional Associations in Dentists) Study. From 2001 to 2006, they completed a baseline questionnaire on lifestyle and health factors including the number of teeth lost (excluding third molars). We followed 19,775 participants (mean age ± standard deviation, 51.4 ± 11.7 years; 1,573 women [8.0%] and 18,202 men [92.0%]) for mortality from pneumonia (ICD-10, J12-J18). Mortality data were collected via the fraternal insurance program of the JDA. The hazard ratios (HRs) were estimated with adjustment for sex, age, body mass index, smoking status, physical activity and diabetes history. During the median follow-up period of 9.5 years, we documented 68 deaths from pneumonia. Participants who were edentulous at baseline were at significantly increased risk of mortality from pneumonia. The multivariable-adjusted HRs were 2.07 (95% confidence interval [CI], 1.09-3.95) for the edentulous and 1.60 (95% CI, 0.83-3.10) for loss of 15-27 teeth relative to loss of 0-14 teeth (trend p = 0.026). The HR per one tooth loss was also significant; 1.031 (95% CI, 1.004-1.060). In conclusion, a large number of teeth lost may indicate an increased risk of mortality from pneumonia in community-dwelling populations.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

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Grant support

This work was supported by Grants-in-Aid from the 8020 (20 teeth until 80 years old) Promotion Foundation [KW] and from the Ministry of Health, Labour and Welfare of Japan (H19-Iryo-Ippan-008) [NH]. The LEMONADE study was supported by Grants for Scientific Research (nos. 14770166 [KW], 16390189 [KW], 20590642 [KW], 23590788 [KW] and 26463161 [MN]) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.