"Refusal of oral care" may be a sign of nutritional risk: A study of 55 adults with intellectual disabilities residing in care facilities suggests that refusal may indicate a higher risk of malnutrition.

January 5, 2026
Kyushu Dental University (Public University Corporation)

A research group led by Lecturer Mayu Izumi of the Unit of Cultivating of Human Resources for Dental Hygienists, Department of Oral Health, Kyushu Dental University (Campus: Kitakyushu City, Fukuoka Prefecture, President: Awano Shuji), investigated the relationship between "refusal of oral care (resistance to brushing teeth, etc.)" observed in daily care and nutritional status in 55 adult residents with intellectual disabilities living in care facilities. As a result, they found that nutritional risk (MNA-SF) was linked.^{* XNUMX}In the group where oral care refusal was observed (as determined by [criteria]), the rate of refusal was high, and even after adjusting for age, gender, etc., it was shown that those who refused oral care had a higher odds of being at nutritional risk.

This research was conducted in collaboration with Dr. Ikujun Ganaha, a practicing physician (Kumamoto Kizuna Dental Clinic, Minami-ku, Kumamoto City, Kumamoto Prefecture), with the cooperation of a facility for people with disabilities in Kumamoto Prefecture.

The results of this study were published on January 2, 2026, in the journal Special Care in Dentistry (online edition) published by Elsevier.

Key points of this research presentation

• Oral care refusal is more common in the nutritionally risk group (nutritionally risk group: 50% refusal, nutritionally normal group: 16.2% refusal).
• Even after adjusting for age, sex, and other factors, refusal of oral care was independently associated with nutritional risk (OR 9.23, 95% CI 1.10–77.33).
• On the other hand, the tongue coating index (TCI)^#2There was no difference in the presence or absence of refusal, suggesting that the behavioral finding of "refusal" may be a more important sign than the oral hygiene status itself.

About the Unit of Cultivating Human Resources for Dental Hygienists, Department of Oral Health, Kyushu Dental University

We provide education necessary for practicing dental preventive procedures, dental treatment assistance, and dental health guidance, which form the foundation of broad dental hygiene activities for all generations. Dental hygiene activities required by society are those that lead to the promotion of health and improvement of quality of life for local residents, based on an understanding of the condition of target individuals at different life stages and health stages, and through multidisciplinary collaboration in accordance with Japan's healthcare system. The Dental Hygienist Training Unit is an educational organization run by clinically experienced dentists and dental hygienists that aims to cultivate individuals who can form the core of a dental hygienist and provide appropriate support to target individuals in any situation.

Research Methodology

• Participants: 55 adults with intellectual disabilities (56.4% male, median age 57 years [32–90 years])
• Period: To be implemented in February-March 2025
• Location: Disability support facility in Kumamoto Prefecture
• Definition of refusal of oral care: The patient expresses resistance or discomfort during oral care provided by staff. This determination is made based on care records from the past month and requires agreement from at least two staff members.
• Nutritional assessment: Classified into "normal (12–14 points)" and "risk/malnourished (0–11 points)" using the MNA-SF (0–14 points) scale.
• Other assessments: Activities of daily living (FIM, Barthel Index), body composition, tongue coating (TCI), etc.

Research results

• In the nutritional risk group (n=24), refusal of oral care was 50% (12/24), compared to 16.2% (5/31) in the nutritionally normal group (n=31).
• In a binary logistic regression analysis (adjusted for age, sex, etc.), refusal of oral care was significantly associated with nutritional risk, with an odds ratio of 9.23 (95% CI 1.10–77.33). (Model discriminative power: AUC 0.90)

Social significance

• In caregiving and support settings, refusals such as "refusing to brush teeth" or "not opening their mouths" are commonly encountered. This study suggests that such refusals are not merely "technical difficulties," but can be signs that help us identify nutritional risks early on.
• If refusal is observed, it is expected that not only will improvements be made to oral care techniques, but also that these improvements will lead to nutritional screening (such as MNA-SF) and multidisciplinary collaboration.

First Author's Comment (Mayu Izumi, Lecturer, Department of Oral Health)

Explanation of terms

*1 MNA-SF: A simplified screening test with 6 items (0–14 points) to assess the risk of malnutrition.
*2 TCI: An index that evaluates tongue coating (tongue buildup) on a scale of 0–18.

Thesis title

Title: Association between oral-care refusal and malnutrition risk among adults with intellectual disabilities: a cross-sectional study in two Japanese residential facilities.
Authors: Maya Izumi, Seijun Ganaha, Sumio Akifusa
Journal: Special Care in Dentistry
DOI: https://doi.org/10.1111/scd.70135.

Acknowledgments

This research was supported by the Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (C) 24K13245.

Contact

Kyushu Dental University Department of Oral Health Sciences Unit of Cultivating of Human Resources for Dental Hygienists
Instructor: Maya Izumi
E-mail: r15izumi■fa.kyu-dent.ac.jp
*When sending, please replace ■ with @.

About Kyushu Dental University, a public university corporation

Kyushu Dental College is the only public dental school and dental college in Japan, and is a "comprehensive university of oral medicine" consisting of a department of dentistry and a department of oral health care. We believe that dentistry is medical care that supports daily life and happiness through "oral health." In the Faculty of Dentistry and the Graduate School of Dentistry, we are committed to nurturing dental professionals. In addition, since its opening in 1914, the attached hospital has continued to serve as a core hospital with dental expertise that is closely connected to the local community.

Outline

• Press release document (PDF: 747KB)