Relationship Between Oral Dysfunction, Physical Disability, and Depressive Mood in Community-Dwelling Elderly Adults in Japan.

Abstract

To the Editor: It is unclear whether self-perceived oral status is associated with objective functional assessment.1, 2 After Japan's long-term care insurance system underwent major reform in 2006, the Japanese Ministry of Health, Welfare, and Labor introduced the 25-item Kihon Checklist (KCL) nationwide as a screening tool to detect elderly adults at risk of requiring care. This tool has become widely used in Japanese communities,3, 4 but few studies have reported the results of KCL screening and its relationship with health status in elderly adults in the community.5, 6 There are three items in the KCL for screening elderly adults at high risk of oral dysfunction: chewing difficulties, choking or coughing, and dry mouth. Despite the importance of oral health in later life, oral health screening in community-dwelling elderly adults has not led to sufficient attention in practice. The objective of the current study was to evaluate the association between oral dysfunction, ADL dependency, and depressive mood using the KCL. The study population comprised 680 individuals aged 65 and older (271 men, 409 women; mean age 76.7 ± 7.7) living in Tosa, Kochi Prefecture, Japan. Using self-reported questionnaires (response rate 53.2%), oral function, activities of daily living (ADLs), and depressive status were assessed in community-dwelling elderly adults in 2014. Oral function was assessed according to three KCL items: “Do you have any greater difficulty eating hard foods than 6 months ago?” “Have you choked on your tea or soup recently?” and “Do you often experience a dry mouth?”4 To assess ADLs, scores on seven items (walking, ascending and descending stairs, feeding, dressing, using the toilet, bathing, grooming) were summed using a rating scale from 0 (completely dependent) to 3 (completely independent) into an ADL score ranging from 0 to 21.7 Physical disability (ADL dependency) was defined as having an ADL score of 20 or lower. Depressive symptoms were screened using the Japanese version of the 15-item Geriatric Depression Scale (GDS-15),8 and depressive mood was defined as having a GDS-15 score of 6 or higher. Statistical analysis was conducted using IBM SPSS Statistics 19.0 (SPSS, Inc., Chicago, IL) with a significance of P < .05. Table 1 shows the results of the multivariate logistic regression analysis for the associations between each of the three oral function items and ADL dependency and depressive mood, with Model 1 adjusted for age and sex and Model 2 adjusted for ADL dependency or depressive state in addition to age and sex. In Model 1, those with chewing difficulty, choking or coughing, and dry mouth had a greater risk of ADL dependency (odds ratio (OR) = 2.1, OR = 2.0, and OR = 2.2, respectively) and risk of depressive state (OR = 2.7, OR = 3.0, and OR = 2.5, respectively). In Model 2, ADL dependency was still significantly associated with chewing difficulty (OR = 1.6) and dry mouth (OR = 1.8). Similarly, depressive mood was still related to chewing difficulty (OR = 2.5), choking or coughing (OR = 2.8), and dry mouth (OR = 2.3). This study found close associations between oral dysfunction, ADL dependency, and depressive mood. Considering the interrelationship between ADL dependency and depressive mood, they were adjusted for each other using age, sex, and depressive mood for the association between ADL dependency and oral dysfunction and age, sex, and ADL dependency for the association between depressive mood and oral dysfunction; there were still significant independent associations between oral dysfunction and ADL dependency and between oral dysfunction depressive mood. Previous studies have reported that community-dwelling elderly adults with chewing difficulties have a higher level of disability and depression.2, 9 In this study, other oral functional problems (e.g., choking, coughing, dry mouth) were also important factors to be screened for in the community. Self-reported dry mouth is reportedly associated with depressive mood,10 and the current findings are in line with those of previous studies. Moreover, ADL dependency was found to be related to dry mouth independent of depressive mood. In conclusion, community-dwelling elderly adults with oral dysfunction have higher levels of disability and depression than those without. These findings suggest that three simple questions can effectively detect oral dysfunction associated with ADL dependency and depressive mood; greater attention should be paid to these questions on oral function in the KCL when screening elderly adults at risk for disabilities and depression. The authors are grateful to the participants and municipal officers in Tosa. This research was supported by Lotte Research Promotion Grant. Author Contributions: Chang, Kimura, Matsubayashi: study concept and design, analysis and interpretation of data, preparation of manuscript. All authors: survey and interpretation of data, manuscript revisions, approval of manuscript. Sponsor's Role: The sponsor had no role in study design, methods, subject recruitment, data collection, data analysis, or preparation of paper.