Abstract
Background
Oral frailty (OF), defined as a multidimensional decline in oral function, is an early marker of functional vulnerability in older adults. Although frailty is linked to cardiovascular disease incidence and prognosis, the relationship between OF, heart disease (HD), and multimorbidity (MM) remains unclear.
Methods and Results
We conducted a cross-sectional analysis of 16,294 community-dwelling adults aged ≥65 years in the 2022 Japan Gerontological Evaluation Study. OF was assessed using the Oral Frailty 5-item Checklist. Among 1,575 participants with HD, we compared those with HD alone and those with HD plus comorbidities (HD+MM). We also compared OF and its components across the 4 groups based on HD and MM status. The overall prevalence of OF was 33.9%, increasing to 42.9% in individuals with HD. OF was significantly more prevalent in the HD+MM group than in the HD-only group (44.3% vs. 36.2%). Respiratory, digestive, immune, and ear diseases were strongly associated with OF. Furthermore, OF, lower Tokyo Metropolitan Institute of Gerontology Index of Competence scores, and higher body mass index were independently associated with a greater comorbidity burden in older adults.
Conclusions
OF is common in older adults with HD, particularly in those with MM. Incorporating oral function assessment into cardiovascular risk evaluation may help identify high-risk individuals and support comprehensive management strategies for the aging population.
Key Words: Heart disease, Multimorbidity, Older adults, Oral frailty
Central Figure.
Research on frailty has advanced substantially in recent years. In older adults, frailty is characterized by diminished physical reserves, dysregulation across multiple physiological systems, and reduced capacity to cope with external stressors due to aging and other factors. This condition results in increased vulnerability to adverse health outcomes, including disease onset, functional decline, disability, and the need for long-term care. Frailty has been identified as an important predictor of disease incidence, poor surgical outcomes, and mortality.1,2
Among the cardiovascular diseases (CVDs), coronary artery disease is the leading cause of death in older adults. The prevalence of valvular disease and the incidence and prevalence of heart failure increase with age. Heart failure is one of the most common causes of hospitalization among individuals aged ≥65 years. Frailty is associated with an increased risk of CVD onset,3 and adversely affects nearly half of patients with heart failure, serving as a significant predictor of death and hospitalization.4,5 Thus, early detection and intervention for frailty are crucial in older adults with heart disease (HD). Recent studies in Japan have also emphasized that comprehensive frailty assessment and the prevention of functional disability are critical for predicting prognosis and the need for long-term care in older patients with HD.6,7
In recent years, oral frailty (OF), which is considered a precursor to systemic frailty, has gained increasing attention in preventive medicine. OF represents an intermediate state between normal oral function and overt oral dysfunction and is characterized by mild decline across multiple oral function domains. These overlapping impairments increase the risk of further deterioration while remaining potentially reversible.8 OF affects dietary diversity, cognitive function, social interactions, and eligibility for long-term care, thereby contributing to an elevated risk of physical disability and death.9,10 The prevalence of OF increases with age; therefore, prevention, early detection, and timely intervention in otherwise healthy older adults are essential. The Oral Frailty 5-item Checklist (OF-5) was recently developed as a simple screening tool that enables OF assessment without the involvement of healthcare professionals.8 It comprises 5 items: reduced number of remaining teeth, difficulty chewing, difficulty swallowing, dry mouth, and speech impairment. A diagnosis of OF is made when ≥2 items are present. In Japan, approximately 40% of community-dwelling older adults have been reported to meet the criteria for OF.8 The multidimensional nature of OF and its functional domains are summarized in Figure 1.
Figure 1.
Conceptual framework of oral frailty and its related functional domains.
Oral functional decline may also affect cardiovascular health through multiple biological and behavioral pathways. Impairments in mastication and swallowing can adversely affect dietary diversity and protein intake, potentially contributing to sarcopenia, increased systemic vulnerability, and immune dysfunction. Chronic oral inflammation, even in the absence of clinically apparent periodontal disease, may promote low-grade systemic inflammation, which is a well-established risk factor for atherosclerosis and cardiovascular events.11 Additionally, oral dysfunction can restrict social participation and physical activity, potentially exacerbating frailty and multimorbidity (MM). Collectively, these pathways suggest that OF may influence cardiovascular health beyond the effects of traditional oral diseases.
Associations between HD and oral diseases have been reported in several epidemiological and clinical studies. For example, periodontal disease progression can facilitate the translocation of oral bacteria into the bloodstream, thereby increasing the risk of atherosclerotic vascular diseases. Oral bacteria have also been implicated in the pathogenesis of infective endocarditis,12–14 and have been reported to be associated with stroke and cardiovascular prognosis.15 However, evidence regarding the association between oral function or OF and HD in older adults remains limited from large-scale population-based studies, although a recent scoping review has made progress in clarifying assessment methods and risk factors.16
Furthermore, older adults frequently experience MM, defined as the concurrent presence of ≥2 chronic conditions. MM is highly prevalent among older adults in Japan and has been associated with increased mortality rates.17 Comorbidities of particular relevance in individuals with HD include diabetes, chronic obstructive pulmonary disease (COPD), and chronic kidney disease, all of which may exacerbate cardiac outcomes by impairing cardiac function and accelerating atherosclerosis.18 In fact, the presence of MM in patients with CVD complicates their management, requiring highly tailored and multidisciplinary approaches.19 Therefore, examining the differences in oral function between older adults with HD alone and those with coexisting MM is clinically important.
The Japan Gerontological Evaluation Study (JAGES) was established as a large-scale social epidemiological project aimed at building a scientific foundation for preventive policies that support health and longevity. The JAGES conducts nationwide surveys of individuals aged ≥65years.20 However, few studies have examined the association between OF or oral functional decline and HD using large-scale epidemiological datasets, limiting the generalizability of existing evidence. Most of the prior research has relied on small clinical samples or focused primarily on periodontal disease rather than the broader domains of oral function. The JAGES dataset provides an opportunity to address this gap by examining the relationship between OF and HD in a large, diverse, and well-characterized population of community-dwelling older adults in Japan.
Clarifying the relationship between OF and HD may inform clinical practice by helping identify older adults who could benefit from early oral health assessment, preventive interventions, and integrated care strategies aimed at reducing cardiovascular and functional vulnerability. Accordingly, this study investigated the association between oral function, including OF, and a history of HD among older adults who were not certified as requiring long-term care, using the large-scale data from the JAGES.
Methods
Participants
This cross-sectional study was based on self-reported questionnaires. Data were obtained from the 2022 JAGES survey, a nationwide survey of community-dwelling adults aged ≥65 years. A total of 192,108 individuals responded to the survey, but for the present analysis, which focused on the OF-5, 16,294 participants who completed all OF-5 items and had no missing data were included (Table 1). All participants were healthy older adults who had not been certified as requiring long-term care. To examine the association between HD and MM, a subsample of 1,575 individuals with a history of HD was selected for analysis (Figure 2). This study was conducted and reported in accordance with the STROBE guidelines.
Table 1.
Oral Frailty 5-Item Checklist
| Component | Questionnaire item in JAGES | Applicable to OF |
|---|---|---|
| Fewer teeth | How many of your natural teeth are left? | 0–19 teeth |
| Difficulty in chewing | Do you have any difficulties eating tough foods compared with 6 months ago? | Yes |
| Difficulty in swallowing | Have you choked on your tea or soup recently? | Yes |
| Dry mouth | Do you often experience having a dry mouth? | Yes |
| Low articulatory oral motor skill | Have you had difficulty with clear pronunciation recently? | Yes |
Figure 2.
Flow diagram of participant selection.
Data Collection and Analysis
We obtained and analyzed existing JAGES data that had already been approved by the Ethics Committee of the Chiba University Faculty of Medicine (approval code: M10460) for use in this study. This study was conducted in accordance with the principles of the Declaration of Helsinki. The collected variables included age, sex, medical history, body mass index (BMI), OF, Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC; a questionnaire designed to assess higher-level functional capacity),21 living alone, and current drinking and smoking habits. The medical history items included HD, hypertension, stroke, diabetes, dyslipidemia, respiratory disease, digestive disease, kidney disease, musculoskeletal disease, trauma, cancer, immune disease, depression, dementia, Parkinson’s disease, eye disease, and ear disease. MM was operationally defined as the presence of ≥2 chronic conditions other than HD.
OF was assessed using criteria consistent with the established OF definitions in Japan and aligned with the JAGES dataset (Table 1). Participants were classified as having OF if they met ≥2 of the 5 OF-5 components.
Activities of daily living (ADL) were assessed using the TMIG-IC, which comprises 13 items. Responses were scored as “0” for “No” and “1” for “Yes,” yielding a total score ranging from 0 to 13, with higher scores indicating better functional capacity. The TMIG-IC, developed with consideration of the Japanese cultural context and lifestyle, is widely used in Japan and internationally recognized for its reliability and validity.21,22
Statistical Analysis
We conducted 3 analyses to examine the association between OF and HD. First, a binary logistic regression was performed with OF status as the dependent variable. The independent variables included age, sex, BMI, TMIG-IC score, living alone, and chronic conditions. These covariates were selected based on their established clinical relevance as potential confounders in the relationship between oral function, frailty, and cardiovascular health, as well as supporting evidence from prior epidemiological studies. Multicollinearity was assessed using variance inflation factors, and no variable exceeded the accepted thresholds. In descriptive analyses, participant characteristics and the prevalence of OF and each OF-5 component were compared across the 4 HD×MM groups (No HD/No MM, No HD/MM, HD-only, and HD+MM). Continuous variables were compared using the Kruskal–Wallis test with post hoc Dunn’s test and Bonferroni adjustment, and categorical variables were compared using Pearson’s chi-square test. The adjusted standardized residuals were inspected to identify the cells contributing to the overall group differences.
As a complementary subgroup analysis among participants with HD (n=1,575), we compared those with HD alone (HD-only) and those with HD and MM (HD+MM) for key variables to facilitate clinical interpretation.
Multiple regression analysis was conducted to identify factors associated with the number of comorbidities, using the total number of chronic conditions as the dependent variable. Statistical analyses were performed using IBM SPSS Statistics version 29.0 (IBM Corp., Armonk, NY, USA), with the significance level set at 5%.
Finally, to assess the specific characteristics of OF components in our study population, we compared the prevalence of each OF-5 item in the HD+MM group with data from previous studies involving community-dwelling older adults and hospitalized patients.23,24
Results
The study included 16,294 participants, comprising 8,205 men (50.4%) and 8,089 women (49.6%), with a median age of 74 years (interquartile range [IQR]: 70–79). OF was identified in 5,525 individuals (33.9%), comprising 2,846 men (51.5%) and 2,679 women (48.5%), with a median age of 75 years (IQR: 71–81). The remaining 10,769 participants (66.1%) were classified as non-OF, comprising 5,359 men (49.8%) and 5,410 women (50.2%), with a median age of 73 years (IQR: 69–78 years).
Logistic regression analysis, with OF as the dependent variable, showed that HD was associated with higher odds of OF (odds ratio [OR]: 1.245) (Table 2). Conditions associated with higher odds of OF (OR ≥1.500) included respiratory disease (1.624), digestive disease (1.520), immune disease (1.616), and ear disease (1.544). Table 3 presents the participant characteristics according to HD×MM status. The prevalence of OF (OF-5) differed significantly across the 4 groups, increasing from No HD/No MM (25.7%) to No HD/MM (34.8%), HD-only (36.2%), and HD+MM (44.3%). Among the OF-5 components, the HD+MM group showed the highest prevalence of fewer teeth (45.6%), chewing difficulty (34.9%), swallowing difficulty (31.8%), dry mouth (26.8%), and low articulatory oral motor skills (6.6%) (Table 3).
Table 2.
Logistic Regression Analysis With Oral Frailty as the Dependent Variable (n=16,294)
| Coefficient | Standard error | OR | 95% CI | P value | |
|---|---|---|---|---|---|
| Age (years) | 0.045 | 0.003 | 1.046 | 1.040, 1.052 | <0.001 |
| Sex (ref: female) | −0.131 | 0.039 | 0.878 | 0.813, 0.947 | 0.001 |
| BMI (kg/m2) | 0.002 | 0.005 | 1.002 | 0.991, 1.012 | 0.730 |
| TMIG-IC (score) | −0.117 | 0.008 | 0.890 | 0.876, 0.904 | <0.001 |
| Living alone (ref: no) | 0.072 | 0.047 | 1.074 | 0.979, 1.179 | 0.130 |
| Heart disease | 0.219 | 0.057 | 1.245 | 1.114, 1.391 | <0.001 |
| Hypertension | 0.080 | 0.036 | 1.084 | 1.011, 1.162 | 0.024 |
| Stroke | 0.298 | 0.110 | 1.347 | 1.086, 1.671 | 0.007 |
| Diabetes | 0.219 | 0.048 | 1.244 | 1.132, 1.367 | <0.001 |
| Dyslipidemia | −0.168 | 0.047 | 0.845 | 0.770, 0.928 | <0.001 |
| Respiratory diseases | 0.485 | 0.076 | 1.624 | 1.399, 1.884 | <0.001 |
| Digestive diseases | 0.419 | 0.074 | 1.520 | 1.315, 1.758 | <0.001 |
| Kidney diseases | 0.086 | 0.062 | 1.089 | 0.965, 1.230 | 0.168 |
| Musculoskeletal diseases | 0.309 | 0.059 | 1.362 | 1.214, 1.529 | <0.001 |
| Trauma | 0.329 | 0.116 | 1.390 | 1.108, 1.745 | 0.004 |
| Cancer | 0.183 | 0.082 | 1.201 | 1.022, 1.412 | 0.026 |
| Immune disorders | 0.480 | 0.138 | 1.616 | 1.233, 2.118 | <0.001 |
| Depression | 0.321 | 0.171 | 1.378 | 0.985, 1.929 | 0.061 |
| Dementia | −0.034 | 0.301 | 0.967 | 0.536, 1.744 | 0.911 |
| Parkinson’s disease | 0.242 | 0.308 | 1.274 | 0.696, 2.332 | 0.432 |
| Eye diseases | 0.146 | 0.046 | 1.157 | 1.058, 1.266 | 0.001 |
| Ear diseases | 0.434 | 0.078 | 1.544 | 1.326, 1.797 | <0.001 |
BMI, body mass index; CI, confidence interval; OR, odds ratio; TMIG-IC, Tokyo Metropolitan Institute of Gerontology Index of Competence.
Table 3.
Participant Characteristics According to HD and MM Status (n=16,294)
| Characteristic | No HD/No MM (n=3,002) |
No HD/MM (n=11,717) |
HD-only (n=260) |
HD+MM (n=1,315) |
P value |
|---|---|---|---|---|---|
| Age, years | 72 (68–76)b | 74 (70–79)c | 75 (72–81)a | 77 (73–82)a | <0.001 |
| Male sex, n (%) | 1,400 (46.6)† | 5,761 (49.2)† | 179 (68.8)† | 865 (65.8)† | <0.001 |
| BMI, kg/m2 | 22.2 (20.3–24.0)c | 22.9 (20.9–25.0)a | 22.8 (21.0–24.9)a,b | 23.1 (21.2–25.5)b | <0.001 |
| TMIG-IC score | 11 (10–13)c | 11 (9–12)a | 11 (9–12)a,b | 10 (9–12)b | <0.001 |
| Current drinking habits, n (%) | 1,315 (43.8) | 4,978 (42.5) | 111 (42.7) | 495 (37.6)† | 0.002 |
| Current smoking habit, n (%) | 428 (14.3)† | 1145 (9.8)† | 29 (11.2) | 85 (6.5)† | <0.001 |
| Living alone, n (%) | 452 (15.1) | 1,816 (15.5) | 40 (15.4) | 201 (15.3) | 0.946 |
| Oral frailty (OF-5), n (%) | 772 (25.7)† | 4,077 (34.8)† | 94 (36.2) | 582 (44.3)† | <0.001 |
| OF-5 total score, points | 1 (0–2)c | 1 (0–2)a | 1 (0–2)a,b | 1 (0–2)b | <0.001 |
| OF-5 components | |||||
| Fewer teeth (0–19 teeth), n (%) | 1,023 (34.1)† | 4,625 (39.5) | 115 (44.2) | 600 (45.6)† | <0.001 |
| Difficulty in chewing, n (%) | 724 (24.1)† | 3,599 (30.7)† | 86 (33.1) | 459 (34.9)† | <0.001 |
| Difficulty in swallowing, n (%) | 504 (16.8)† | 2,790 (23.8)† | 57 (21.9) | 418 (31.8)† | <0.001 |
| Dry mouth, n (%) | 454 (15.1)† | 2,621 (22.4)† | 59 (22.7) | 352 (26.8)† | <0.001 |
| Low articulatory oral motor skill, n (%) | 104 (3.5)† | 520 (4.4) | 10 (3.8) | 87 (6.6)† | <0.001 |
Values are presented as median (IQR) or n (%). Continuous variables: Kruskal–Wallis test; post hoc pairwise comparisons: Dunn’s test with Bonferroni adjustment. a–cNot significantly different (Bonferroni-adjusted P<0.05). Categorical variables: Pearson’s chi-square test. †|Adjusted standardized residual| >1.96. BMI, body mass index; HD, heart disease; IQR, interquartile range; MM, multimorbidity; OF-5, Oral Frailty 5-item Checklist; TMIG-IC, Tokyo Metropolitan Institute of Gerontology Index of Competence.
Among the 1,575 participants with a history of HD, 1,044 were men (66.3%) and 531 were women (33.7%), with a median age of 77 years (IQR: 72–82 years). Among the participants with HD, 260 had HD alone, and 1,315 had HD with additional comorbidities (HD+MM group). A total of 676 participants (42.9%) had OF, including 94 (36.2%) in the HD-only group and 582 (44.3%) in the HD+MM group (P=0.016). The HD+MM group was older (P<0.001), had lower TMIG-IC scores (P<0.001), and included fewer current smokers (P=0.008) than the HD-only group. Among the OF-5 components, difficulty swallowing was more common in the HD+MM group (31.8%) than in the HD-only group (21.9%), consistent with the overall group differences shown in Table 3. Detailed comparisons between the HD-only and HD+MM groups are provided in the Supplementary Table.
Multiple regression analysis, using the number of comorbidities other than HD as the dependent variable, showed that OF (P<0.001), TMIG-IC (P=0.001), and BMI (P=0.002) were significantly associated with the number of comorbidities (Table 4).
Table 4.
Multiple Regression Analysis With the Number of Comorbidities Other Than HD as the Dependent Variable
| Partial regression coefficient |
Standard error |
Standardized partial regression coefficient |
t value | P value | |
|---|---|---|---|---|---|
| Age (years) | 0.008 | 0.005 | 0.039 | 2 | 0.125 |
| Sex (ref: female) | 0.107 | 0.074 | 0.038 | 1 | 0.149 |
| TMIG-IC (score) | −0.051 | 0.015 | −0.091 | −3 | 0.001 |
| BMI (kg/m2) | 0.031 | 0.010 | 0.078 | 3 | 0.002 |
| Current smoking habit (ref: none) | −0.195 | 0.131 | −0.038 | −1 | 0.138 |
| OF-5 (ref: none) | 0.328 | 0.069 | 0.121 | 5 | <0.001 |
Adjusted R2=0.033. Abbreviations as in Table 3.
Discussion
We investigated the prevalence of OF and its associated factors among community-dwelling older adults aged ≥65 years who were not certified as requiring long-term care, using large-scale data from the JAGES. Specifically, we examined the prevalence of OF among older adults with HD alone and among those with HD accompanied by other comorbidities.
The overall prevalence of OF in all participants was 33.9%. Among older adults with HD, the OF prevalence was 42.9%, comprising 36.2% in those with HD alone (HD-only group) and 44.3% in those with HD and additional comorbidities (HD+MM group). The prevalence of OF has been reported to range from 36.7% to 44.0% among relatively healthy community-dwelling older adults,23–25 indicating that the prevalence observed in the present study was slightly lower. The absolute prevalence of OF increased by approximately 10 percentage points in the HD-only group and further increased in the HD+MM group, suggesting that comorbidities are associated with increased prevalence of OF. Furthermore, in our revised analysis categorizing all participants into 4 groups based on HD and MM status, we found that MM independently contributes to OF even in the absence of HD. This finding indicates that the cumulative burden of multiple chronic conditions plays a crucial role in oral functional decline, beyond the risks associated with cardiovascular status alone. Logistic regression analysis showed that conditions with OR >1.50 included respiratory disease, digestive disease, immune disorders, and ear disease. The OR for HD was 1.245, comparable to that of cancer and diabetes, indicating that HD is a contributing factor to OF.
Regarding the association between OF and specific diseases, respiratory diseases have been reported to indirectly increase the risk of respiratory infections through pathways involving OF, malnutrition, and oral dysbiosis.26,27 Immune disorders may contribute to sarcopenia via systemic inflammation and metabolic abnormalities, whereas digestive diseases may lead to malnutrition due to impaired digestive function, thereby indirectly increasing the risk of OF.26,28–31
To contextualize the OF-5 component profile observed in this study, we compared the component prevalence in the HD+MM group (Group A) with the values reported in previous Japanese studies (Table 5). Specifically, we contrasted our findings with data from healthy community-dwelling older adults and hospitalized patients reported in prior studies: healthy community-dwelling older adults in Japan23 (Group B) and hospitalized patients in Japan24 (Group C) (Table 5). Group A exhibited an approximately 10% higher prevalence of fewer teeth and an approximately 15% higher prevalence of chewing difficulties than Groups B and C. Fewer teeth is associated with subjective and objective declines in masticatory ability, particularly when <20 teeth remain, as evidenced by decreased performance in measures such as gummy chewing tests, maximum bite force, and masticatory performance scores.32,33 Given that tooth loss has been identified as a risk factor for CVD and death,34–41 the observed higher prevalence of fewer teeth in older adults with HD in our study suggests a potential link between their cardiovascular status and oral functional decline related to tooth loss.
Table 5.
Correspondence Rates Between OF-5 Items Used in This Study and Those Reported in Previous Studies
| Group A This study |
Group B Kusunoki et al.23 |
Group C Kusunoki et al.24 |
|
|---|---|---|---|
| Subjects | Community-dwelling older adults with HD+MM |
Healthy community-dwelling older adults in Japan |
Hospitalized patients in Japan |
| Average age (years) | 77.2±6.4 | 74.0±5.8 | 77.6±7.3 |
| Fewer teeth | 45.6% | 33.8% | 33.3% |
| Difficulty in chewing | 34.9% | 19.8% | 20.7% |
| Difficulty in swallowing | 31.8% | 25.8% | 27.8% |
| Dry mouth | 26.8% | 30.8% | 37.4% |
| Low articulatory oral motor skill | 6.6% | 36.0% | 11.5% |
Abbreviations as in Table 3.
The prevalence of dry mouth was slightly lower in Group A than in Group B. In patients with heart failure, antihypertensive medications are commonly prescribed and may cause drug-induced xerostomia.11 Xerostomia assessed by the OF-5 is based on subjective self-report; therefore, objective assessments using devices such as oral moisture meters are required. Differences were also observed in tongue motor function among Groups A, B, and C. Groups A and C relied on subjective responses, whereas Group B used objective evaluations using oral diadochokinesis devices. As the OF-5 is a self-reported screening tool, discrepancies may occur between questionnaire responses and objective oral examinations, which may result in the under-recognition of subclinical or latent oral functional decline.8,24,42 Therefore, combining subjective assessments with simple objective measures is necessary for a more accurate evaluation of oral function.
In this study, 16.5% of the participants with HD belonged to the HD-only group, whereas 83.5% belonged to the HD+MM group, indicating that older adults with HD frequently have multiple comorbidities. Common comorbidities include visual impairment, diabetes, and COPD.43 From an oral health perspective, periodontitis has been independently associated with diabetes, COPD, and CVD,44 and is considered a key contributor to tooth loss. Meta-analyses and reviews have also reported associations between retinal vascular lesions related to visual impairment and systemic outcomes such as stroke, myocardial infarction, and mortality risk, as well as links between periodontitis and age-related macular degeneration, diabetic retinopathy, and glaucoma. Collectively, these findings suggest that effective management of periodontitis may help prevent OF and contribute to the control of comorbidity progression.
The HD+MM group demonstrated significantly lower TMIG-IC scores than the HD-only group. A cutoff score of 11 has been used to identify low ADL,45 suggesting that the HD+MM group had reduced functional capacity. Furthermore, the HD+MM group exhibited a significantly higher prevalence of OF, as assessed by the OF-5, with particularly notable differences in swallowing difficulties. Swallowing difficulties in older adults are multifactorial, involving factors such as inflammation, reduced energy intake, aging, low ADL, poor oral hygiene, and antipsychotic medication use. Polypharmacy has been reported in 74–95% of patients with HD.46–48 In patients with heart failure, polypharmacy may impair taste sensitivity and reduce energy intake, thereby increasing the risk of malnutrition.49 In patients with HD+MM, a greater number and variety of medications may further contribute to swallowing difficulties. The prevalence of dysphagia among hospitalized patients with heart failure is 23.6%, with 9.4% being discharged while still experiencing dysphagia.50 Collectively, these findings underscore the importance of dental and oral health management in maintaining and improving oral function in this population.
Compared with the HD-only group, the HD+MM group was more prone to OF, exhibited greater declines in ADL, showed progression of physical frailty, and had an increased risk of transitioning to a care-dependent state. Although BMI remained within the normal range in the HD+MM group, the reduced ADL suggested decreased muscle mass. The coexistence of reduced muscle mass and normal or high BMI may result in sarcopenic obesity, which has been reported to confer a higher cardiovascular risk than sarcopenia or obesity alone.51 Therefore, in patients with HD, regular assessments of body composition, including muscle mass, body fat, and body water, are essential to guide medical support and prevent disease progression.
This study revealed that the risk of OF increased with the number of comorbidities in patients with HD. To our knowledge, no previous population-based studies have specifically examined the impact of MM on OF, as assessed by the OF-5, in older adults with HD. Furthermore, as the number of comorbidities increased, ADL declined, and BMI increased. Elevated BMI may increase the risk of lifestyle-related diseases potentially leading to further accumulation of comorbidities. Although the “obesity paradox” has been reported in patients with heart failure, in which a higher BMI is associated with a lower mortality risk and better prognosis,52 decreased muscle mass due to reduced ADL highlights the importance of monitoring sarcopenic obesity. Physical rehabilitation and regular exercise of sufficient intensity may help prevent sarcopenia, reduce frailty progression, and ultimately reduce the risk of OF. Moreover, the usefulness of objective frailty assessment in predicting clinical outcomes has been widely demonstrated, even in older patients with severe CVDs.53 Given the high likelihood of latent OF in patients with multiple comorbidities, proactive community-based screening using the OF-5 is warranted to enable early detection and appropriate dental management, thereby supporting preventive care strategies for older adults with HD.
Study Limitations
First, it was a cross-sectional study and conducted at a single time point, preventing the evaluation of long-term changes and limited causal inference. Therefore, the observed associations should be interpreted without assuming temporal ordering, and reverse causation cannot be ruled out. Consequently, the process by which patients with HD alone progress to MM and develop OF remains unclear, as does the time frame for progression from OF to frailty and care dependency. Future longitudinal studies using JAGES data are required to address these questions. Second, the diagnosis of HD was based on self-reported questionnaire responses. Therefore, we could not distinguish between specific types of HD, such as ischemic HD, arrhythmia, or valvular disease, which may have different effects on OF. Finally, although MM is generally defined as the presence of ≥2 chronic diseases, the specific number and types of chronic conditions have not been standardized.54,55 Further efforts are required to establish a unified and consistent definition.
Conclusions
This study demonstrated that OF was more prevalent among Japanese community-dwelling older adults with HD than among those without HD, and that the burden of oral functional decline increased in the presence of MM. Participants with HD tended to have fewer remaining teeth, and comorbidities such as diabetes and COPD were strongly associated with the occurrence of OF. These findings suggest that older adults with HD and MM should be carefully monitored for oral functional decline, particularly swallowing difficulties, and that the likelihood of OF increases with the number of chronic comorbidities present.
These findings highlight the need for future longitudinal studies to elucidate the temporal and causal relationships among HD, MM, and oral functional decline. Intervention studies are warranted to determine whether maintaining or improving oral function contributes to better cardiovascular and functional outcomes. From a practical perspective, incorporating routine oral function assessments into cardiovascular and primary care, promoting regular dental visits, and strengthening collaboration between medical and dental professionals may facilitate early detection and prevention of OF in older adults with MM. Such integrated approaches could help preserve functional independence and reduce progression toward frailty and care dependency in this population.
Disclosures
The authors declare no conflicts of interest with respect to this study.
IRB Information
Ethical approval for the JAGES project 2022 was obtained from the Ethics Committee of the Chiba University Faculty of Medicine (approval code: M10460). Participants were informed that participation was voluntary, and completion of the survey was considered implied consent to participate.
Author Contributions
Conceptualization, N.O. and Y.C.; Methodology, N.O., A.Y. C.M., H.T. and Y.C.; Data curation, N.O., A.Y. and C.M.; Data analysis, C.M., Y.S. and J.A.; writing – original draft preparation, N.O. and A.Y; writing – review and editing, C.M., Y.S., J.A., H.T. and Y.C.; supervision, H.T. and Y.C.; project administration, Y.C.; funding acquisition, Y.C. All authors have read and agreed to the published version of the manuscript.
Supplementary Files
Supplementary Table.
Acknowledgments
This study used data from the Japan Gerontological Evaluation Study (JAGES). We thank Editage (www.editage.jp) for the English language editing.
Funding Statement
Funding: This study was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant number 23K24648).
Data Availability
The data supporting the findings of this study are available from the Japan Gerontological Evaluation Study (JAGES). Restrictions apply to the availability of these data, which were used under a license for this study. Data are available from https://www.jages.net/data_application/ with the permission of the Japan Gerontological Evaluation Study (JAGES).
Declaration of Generative AI and AI-assisted technologies in the writing process: During the preparation of this manuscript, the authors used Microsoft Copilot to correct grammatical errors and improve the readability of the first author’s early draft. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the published article.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplementary Table.
Data Availability Statement
The data supporting the findings of this study are available from the Japan Gerontological Evaluation Study (JAGES). Restrictions apply to the availability of these data, which were used under a license for this study. Data are available from https://www.jages.net/data_application/ with the permission of the Japan Gerontological Evaluation Study (JAGES).
Declaration of Generative AI and AI-assisted technologies in the writing process: During the preparation of this manuscript, the authors used Microsoft Copilot to correct grammatical errors and improve the readability of the first author’s early draft. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the published article.