Association Between the Number of Remaining Teeth and Body Mass Index in Japanese Inpatients with Schizophrenia

Abstract

Purpose

There is little evidence regarding the effects of dental status on body mass index (BMI) in inpatients with schizophrenia. Thus, we performed a cross-sectional study to explore the associations between the number of remaining teeth and BMI in Japanese inpatients with schizophrenia.

Patients and Methods

We performed multiple regression analysis to assess the effects of potential predictors (age, sex, number of remaining teeth, number of antipsychotics prescribed, chlorpromazine equivalent dose, and antipsychotic type) on BMI in 212 inpatients with schizophrenia. We then compared the number of remaining teeth between inpatients with schizophrenia and the Japanese general population (3283 individuals) from the Japan Dental Diseases Survey 2016, using an analysis of covariance with age and sex as covariates.

Results

Multiple regression analysis showed that the number of remaining teeth and the number of antipsychotics prescribed were significantly correlated with BMI (standardized regression coefficient = 0.201 and 0.235, respectively). In the analysis of covariance, inpatients with schizophrenia had significantly fewer remaining teeth compared with the Japanese general population (mean 14.8 [standard deviation: 10.9] vs mean 23.0 [standard deviation: 8.1]).

Conclusion

These results suggested that tooth loss and antipsychotic polypharmacy affect BMI in inpatients with schizophrenia, and that inpatients with schizophrenia lose more teeth compared with the general population.

Keywords:

• antipsychotic polypharmacy
• body mass index
• oral health
• tooth loss

Acknowledgments

The authors greatly appreciate the involvement of all participants and staff of the participating psychiatric hospitals: Shirone Midorigaoka Hospital, Suehirobashi Hospital, Niigata Psychiatric Center, Kurokawa Hospital, Minamihama Hospital, and Kohdo Hospital. We thank Benjamin Knight, MSc., from Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.

This work was supported by Grants-in-Aid for Scientific Research (19K08068 to T Sugai) from the Japan Society for the Promotion of Science. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Disclosure

Shin Ono received grant or research support from the Hospitals Bureau Niigata Prefecture Government. Toshiyuki Someya reports grants and personal fees from Astellas Pharma Inc., Eli Lilly Japan K.K., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Co., Mochida Pharmaceutical Co., Ltd., MSD K.K., Novartis Pharma K.K., Otsuka Pharmaceutical Co., Ltd., Shionogi Co., Ltd., and Sumitomo Dainippon Pharma Co., Ltd. outside the submitted work. All other authors declare that they have no potential conflicts of interest in this work.