Teeth and physical fitness in a community-dwelling 40 to 79-year-old Japanese population

Abstract

Purpose

Decline in the number of teeth and physical fitness begins from 40 years of age; however, several epidemiological studies have identified relationships between oral conditions and physical performance parameters in community-dwelling elderly population. The aim of this study was to validate the relationship between the muscle mass and its function and oral conditions (number of teeth and dental occlusion) after 40 years of age in a community-dwelling population in Japan.

Materials and methods

The subjects comprised of 552 volunteers (198 males and 354 females, 40–79 years) who participated in the Iwaki Health Promotion Project in 2013. Multiple linear regression analyses were performed with the measures of the muscle mass and its function as objective variables and the measures of the number of teeth, age, body mass index, medical history, serum albumin concentration, smoking status, habitual alcohol intake, marital status, education levels, and exercising habits as explanatory variables. The relationships between the Eichner index and the muscle mass and its function were analyzed using analysis of covariance, with adjustment for confounding factors.

Results

After adjusting for confounding factors, the number of teeth was shown to be an independent risk factor for the timed 10 m walk test (in females) and the skeletal muscle mass of the whole body (in males). The results also revealed that the timed 10 m walk test was significantly correlated with the Eichner index (Classes A and C in females were correlated).

Conclusion

This cross-sectional study on a Japanese community-dwelling population revealed relationships between oral conditions and the muscle mass and its function. However, the interpretation of our results was hampered by a lack of data, including those on socioeconomic status and longitudinal observations. Future research exploring teeth loss and the muscle mass and its function is warranted.

Keywords:

• number of teeth
• sarcopenia
• timed 10 m walk test
• hand grip strength
• skeletal muscle mass

Acknowledgments

The authors thank all their coworkers in this study (especially Youhei Sekine, Daisuke Chiba, Satou Satoshi, Rina Tanaka, Hiroshi Ishizaki, Takao Noguchi) for skillful contributions to the collection and management of the data. This study was supported by grants-in-aid for Scientific Research (15K20847) from the Japanese Ministry of Education, Culture, Sports, Science, and Technology and research aid from the Foundation Institute of Geriatric Medicine and Dentistry in Tokyo.

Author contributions

AI conceived the study and wrote the initial draft of the manuscript. IT designed the study, conducted the statistical analyses, interpreted the data, and assisted in drafting the manuscript. KS contributed to the study design and interpretation of the results and had full access to all the data in the study. IT and KS participated in the data collection. WK took responsibility for the integrity of the data and the accuracy of the data analysis. All authors have read and approved the final manuscript. All authors contributed toward data analysis, drafting and revising the paper and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.