Number of teeth and medical care expenditure

LETTER TO THE EDITOR

Number of teeth and medical care expenditure
Midori Tsuneishi1），Tatsuo Yamamoto2），Yasuyuki Okumura3）
Genta Kato4），Takuo Ishii5），Shigeo Sugiyama6），Takeyuki Yamaguchi1，6）
Tamotsu Sato6），and Toshihiko Makino1，6）1）Japan Dental Association Research Institute, Tokyo, Japan
Division of Dental Sociology, Department of Oral Science, Graduate School of Dentistry, Kanagawa Dental University,Yokosuka, Japan
3）
Research Department, Institute for Health Economics and Policy, Association for Health Economics Research and Social
Insurance and Welfare, Tokyo, Japan4）
Solutions Center for Health Insurance Claims, Kyoto University Hospital, Kyoto, Japan
5）
Tokyo Dental College, Tokyo, Japan
6）
Japan Dental Association, Tokyo, Japan
2）

Studies have shown that poor dental health isand 654,410 eligible patients in their 50s, 60s, andassociated with general health conditions. For

70s, respectively. For each patient with chronic

example, tooth loss is associated with an increased

periodontitis, we identified the number of teeth by1）

2）

risk of cardiovascular disease , dementia , depen-using dental care claims and summed up medical

dence in activities of daily living3）, and premature

care expenditure by using medical care claims in3）

death . However, little is known about the associa-

the same month. We calculated median medicaltion between the number of teeth and medical careexpenditure stratified by the number of teeth

expenditure.

ranging from 1–28 and age groups (50–59, 60–69,

We conducted a cross-sectional study of patientsand 70–79 years) (Figure).

aged 50-79 years with a diagnosis of chronic peri-

To describe associations between number ofodontitis (ICD-10 code: K051) in April 2013 using

teeth (independent variable) and medical expendi-

the National Database of Health Insurance Claimture (primary outcome) while controlling for sex,Information and Specified Medical Checkups

we also constructed generalized linear models(NDB). The Japanese government developed thewith a gamma distribution and log-link function by

NDB that includes almost all claims for medical

using maximum likelihood estimation. As the likeli-and dental care in Japan4）, a country with a popu-hood ratio test for interaction between age groups

lation of 127 million. We identified 327,689, 610,087,

and number of teeth was statistically significant(p<.001), the models were constructed by age
group. The models showed that medical careexpenditure increased by 2.4% per each tooth lostin patients in their 50s (multiplicative effect, 0.98;【Correspondence】
Dr. Midori Tsuneishi
Japan Dental Association Research Institute, Tokyo, Japan
Tel：+81-33-262-9346 Fax：+81-33-262-8810
E-mail： tsuneishi_mi@jda.or.jp

95% confidence interval [CI], 0.97-0.98). The association became attenuated in patients in their 60s(multiplicative effect, 0.98; 95% CI, 0.98–0.99) and in
those in their 70s (multiplicative effect, 0.99; 95%
̶ 36 ̶

ヘルスサイエンス・ヘルスケア

Volume 17，No.1（2017）

Fig Median medical care expenditure for different numbers of teeth in subjects aged 50-59, 60-69, and 70-79.

References

CI, 0.99–0.99).
Patients with more teeth spent less on medicalcare. Periodontitis and dental caries are major
causes of tooth loss5）. These diseases are associated with socio-economic status, smoking, and accessto health-care services, all of which are also associated with non-communicable diseases. Dentalcaries and periodontitis develop earlier than noncommunicable diseases. Tooth loss may be a summative measure of physical, psychological, andsocial stress. Sharing information about number ofteeth with both medical and dental care providers
and patients may provide a valuable impetus for
improving cooperation in dental and medical
health-care.
Conflict of Interest : We declare no competinginterests.
Funding source : This study was funded by Japan
Dental Association.
Ethics committee approval : The protocol of thisstudy was reviewed and approved by the Ethics
Committee at Tokyo Dental College (No. 557).

̶ 37 ̶1） Watt RG, Tsakos G, de Oliveira C, et al. Tooth loss
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