Relationship between risk of oral frailty and awareness of oral frailty among community-dwelling adults: a cross-sectional study

We aimed to investigate the relationship between the risk of oral frailty and awareness of oral frailty among Japanese adults in an adult dental health field study conducted in Kanagawa Prefecture. Questionnaire data from a total of 5051 individuals (1907 males, 3144 females; mean age; 59.9 years) were used. The risk of oral frailty was assessed using the Oral Frailty Index-8. Of the participants, 1418 (28.1%) had a high risk of oral frailty and 1495 (29.6%) had knowledge of oral frailty. Logistic regression analysis indicated that the risk of oral frailty was significantly associated with awareness of oral frailty. We further found that awareness of oral frailty was significantly related to gender (female), age (20–39 compared to 70–79, ≥ 80), residential areas (Yokohama compared to Kawasaki, Sagamihara), exercise habits (yes), eating a balanced diet (yes), consciousness of oral health (yes), risk of oral frailty (low) and outpatient category (hospital visit). For groups with low levels of awareness obtained from the results of this study, it is necessary to consider the means of accessibility and increase awareness further.


Definition and assessment of OFI-8
The presence or absence of risk of oral frailty was evaluated based on eight items, which was a modification of the method described by Tanaka et al 10 .The OFI-8 is an eight-item screening questionnaire that integrates oral health-related behaviors and frailty concepts.OFI-8 doubles the score of the three higher priority items for the most important elements of oral frailty ("tooth loss, " "subjective chewing difficulties, " and "subjective swallowing difficulties").Total OFI-8 scores ranged from 0 to 11 points, with higher scores indicating poorer oral health.Each question was extracted from a questionnaire that is widely used in Japan.All items were scored as follows: 1. "Do you have any difficulties eating tough foods compared to 6 months ago?" (Yes, 2 points).2. "Have you choked on your tea or soup recently?"(Yes, 2 points).3. "Do you use dentures?"(Yes, 2 points).4. "Do you often have a dry mouth?" (Yes, 1 point).5. "Do you go out less frequently than you did last year?"(Yes, 1 point).6. "Can you eat hard foods like squid jerky or pickled radish?" (No, 1 point).7. "How many times do you brush your teeth in a day?" (< 3 times/day, 1 point).8. "Do you visit a dental clinic at least annually?"(No, 1 point).
The higher the OFI-8 score, the higher the risk of oral frailty, that is, 0-2 points indicates low risk; 3 points, moderate risk; and 4-11 points, high risk.A score of 4 ≥ points indicates the necessity of a dental checkup, as older adults with such a score are at high risk of new-onset oral frailty and new long-term care needs certification 10 .Therefore, the OHI-8 score of 4 ≥ points were defined as high risk of oral frailty in the present study 11 .
We assessed participant's awareness of oral frailty by asking whether they knew of oral frailty.Respondents who answered 'I know what it means' or 'I know the term' were categorized as 'yes'; respondents participants were also asked "Do you eat a balanced diet?" (Yes or no), and "Are you consciousness of oral health?"(Yes or no).

Statistical analysis
Descriptive statistics were used to characterize the study population and compare groups at high risk of oral frailty and with awareness of oral frailty.Student's t-test, Mann-Whitney U statistic, or the Chi-squared test were used where appropriate.
Odds ratios and 95% confidence intervals were calculated using logistic regression.For the risk of oral frailty, according to previous studies 6,10 and descriptive statistics (p < 0.10), the following variables were selected based on confounder variables: gender, age, diabetes mellitus, heart disease, pneumonia, cerebrovascular disease, exercise habits, eating a balanced diet, consciousness of dental health, awareness of oral frailty and outpatient category.For awareness of oral frailty, from descriptive statistics (p < 0.10), the following variables were selected based on confounder variables: gender, age, residential area, diabetes mellitus, cerebrovascular disease, exercise habits, smoking habits, eating a balanced diet, consciousness of oral health, risk of oral frailty, and outpatient category.Statistical analysis was performed using the software package IBM SPSS Statistics (v.29.0, SPSS Japan Inc.) at a significance level of 0.05.

Results
Of the total number of participants, 3633 (71.9%) had a low risk of oral frailty, and 1418 (28.1%) had a high risk of oral frailty.Comparisons of participant characteristics according to the risk of oral frailty are presented in Table 1.
A high risk of oral frailty was significantly associated with older age, diabetes mellitus (yes), heart disease (yes), pneumonia (yes), cerebrovascular disease (yes), exercise habits (no), eating a balanced diet (no), consciousness of oral health (no), awareness of oral frailty (no), and outpatient category (home visit).Table 2 presents the results of binomial regression analysis with the risk of oral frailty as the dependent variable.High risk of oral frailty was significantly related to gender (male), age (20-39 compared to 40-49, 50-59, 60-69, 70-79, ≥ 80), diabetes mellitus (yes), heart disease (yes), exercise habits (no), eating a balanced diet (no), consciousness oral health (no), awareness of oral frailty (no) and outpatient category (home visit) even after adjusting for variables.www.nature.com/scientificreports/residential area, diabetes mellitus (no), cerebrovascular disease (no), exercise habits (yes), smoking habits (no), eating a balanced diet (yes), consciousness of oral health (yes), risk of oral frailty (low), and outpatient category (hospital visits).Table 4 shows results of the binomial regression analysis with awareness of oral frailty as the dependent variable.Awareness of oral frailty was significantly related to gender (female), age (20-39 compared to 70-79, ≥ 80), residential areas (Kawasaki, Sagamihara), exercise habits (yes), eating a balanced diet (yes), consciousness of oral health (yes), risk of oral frailty (low), and outpatient category (hospital visit) even after adjusting for variables.

Discussion
Herein, we investigated whether the risk of oral frailty is associated with awareness of oral frailty in community dwelling Japanese adults.Our results showed that the risk of oral frailty was significantly associated with awareness of oral frailty.We further found that awareness of oral frailty was to be influenced by factors such as gender, age, residential area, exercise habits, eating a balanced diet, consciousness of oral health, risk of oral frailty and outpatient category.This is the first study to examine the association between risk of oral frailty and awareness of oral frailty.These results suggest the importance of disseminating oral frailty awareness particularly to populations with low awareness levels, thus preventing oral frailty.It is especially important to inform oral frailty high-risk individuals in dental clinics, since the population of this study was dental clinic patients.
Our results showed that 29.6% of participants recognized oral frailty.The target of 50%, set by the Japanese Dental Association by 2025 has not yet been reached.The high risk of oral frailty among those with no awareness of it indicates the importance of raising awareness.For groups with low levels of awareness obtained from the results of this study, it is necessary to consider the means of accessibility and to further increase awareness.Most oral health problems in older adults can be prevented through routine oral healthcare 12 .Surprisingly, individuals at high risk of oral frailty were also found in the younger age group.Therefore, there is a need to raise awareness of the importance of oral function not only among the older people but also among the younger population.Thus, healthcare providers should develop educational programs that provide detailed oral health knowledge that can be directly linked to oral health behavior.It is necessary to devise and implement not only one-time education programs, but also to plan for continuous oral health education.
The risk of oral frailty is also associated with age, diabetes mellitus, heart disease, cerebrovascular disease, exercise habits, and balanced diet.Previous studies have shown that oral health status is associated not only with aging 13,14 , but also with systemic disease 15 .Oral health literacy, including exercise habits and balanced diet, also affects oral health status 16 .Oral health problems such as tooth loss, decline in swallowing function, and low tongue pressure are interrelated and no single oral health condition assessment can capture these phenomena 3 .Oral frailty is a series of processes that lead to age-associated changes in various oral conditions, such as the number of teeth present, oral hygiene, and oral dysfunction, together with a decreased interest in oral health 2 .Therefore, early recognition of declining oral health status and promotion of treatment of declining oral function, especially in high-risk populations, may be effective in preventing oral frailty.
The following reasons can be considered as possible reasons why awareness of oral frailty was associated with risk of oral frailty.Poor oral knowledge has been proposed as a causal factor for disparities in oral health outcomes 17 .Oral health education is effective in modifying oral health behavior 18,19 .For instance, knowledge of dental flossing was positively associated with the use of dental floss and regular dental checkups 20 .In addition, some reports have suggested that acquiring dental knowledge from dental clinics effectively induces good oral www.nature.com/scientificreports/health behaviors, which contributes to the achievement and maintenance of superior periodontal status 7,20,21 .Furthermore, awareness of the 8020 movement was significantly associated with regular dental visits 9 .They may be willing to do regular dental visits to retain 20 or more of one`s own teeth.Altogether, there is general agreement that good dental awareness and good oral health behavior are correlated.
In addition, factors related to awareness of oral frailty were gender, age, residential area, exercise habits, eating a balanced diet, consciousness of oral health, risk of oral frailty, and outpatient category.A previous study showed that females possessed greater knowledge of oral health and a more positive attitude toward dental visit than males 9 .Furthermore, older age is associated with lower levels of oral health knowledge 22 .Oral health knowledge also varies regionally owing to a combination of factors, including cultural practices, access to health care, and educational initiatives 23,24 .Regarding residential area, there were differences Kawasaki are Sagamihara compared to Yokohama.Differences in health policies between the regions may have an impact.To increase residents′ awareness of oral frailty, municipalities are conducting various projects such as holding lectures and training resident volunteers.Yokohama is a large city with a large budget and may have an extensive program related to public awareness.Further analysis is needed to obtain this information in the future.Additionally, oral health literacy, including exercise habits and eating a balanced diet is related to oral health knowledge 25 .Therefore, our results are consistent with the findings of a previous study and provide useful information about raising awareness regarding oral frailty.
The present study had certain limitations.First, causal associations could not be determined because this was a cross-sectional study.Prospective follow-up studies are required to confirm these findings.Second, other possible www.nature.com/scientificreports/confounders, such as life style 26 , education level 27 , social capital 28 , sense of coherence 29 and self-efficacy 30 were not included in this study.Third, it is not known where they obtained information about oral frailty.Clarifying the source of the information is an issue for future study, as it is important for the future dissemination of oral frailty.It is also unclear to what extent those who reported "know" knew the specific of the term.It is important to assess specific health behaviors rather than merely knowing the terminology.Forth, we evaluated the risk of oral frailty using OFI-8 across various age group.The appropriateness of using OFI-8 in young adults has not yet been studied.The reason why we did not limit the subjects in this study to those aged 65 years and older was to convey the importance of taking measures to prevent oral frailty from a young adulthood.The fact that the percentage and ORs of the high risk of oral frailty increase age (Tables 1 and 2) suggests that OFI-8 may be somewhat adaptable to those under 65 years of age.Further studies are required to confirm the appropriateness of using OFI-8 in young adults.

Conclusions
Risk of oral frailty was significantly associated with awareness of oral frailty.Additionally, awareness of oral frailty was found to be influenced by factors such as gender, age, residential area, exercise habits, eating a balanced diet, consciousness of oral health, risk of oral frailty, and outpatient category even after adjusting for possible confounders.
All data used in the analysis were anonymous and the requirement for informed consent was waived based on the Ethics Guidelines for Medical and Biological Research Involving Human Subjects in Japan.The corresponding author signed a memorandum of understanding with Kanagawa Prefecture regarding use of the survey data.Kanagawa Prefecture issue clearance for secondary analysis of survey data (approval No. KEU2642).The study was carried out in accordance with the revised Declaration of Helsinki.

Table 1 .
Table3compares participant characteristics according to their awareness of oral frailty, 1495 (29.6%) had awareness of oral frailty.Awareness of oral frailty (yes) was significantly affected by gender (female), age, Characteristics of the study participants and subjects with high risk of oral frailty.

Table 2 .
Factors associated with the high risk of oral frailty by binomial logistic regression analysis with stepwise variable selection.CI Confidence interval, OR Odds ratio.Dependent variable: risk of oral frailty (1: high, 0: low).Independent variables entered the model were gender, age, diabetes mellitus, heart disease, cerebrovascular disease, exercise habits, eating a balanced diet, consciousness of dental health, awareness of oral frailty, and outpatient category.

Table 3 .
Characteristics of the study participants and subjects with having awareness of oral frailty.

Table 4 .
Factors associated with awareness of oral frailty by binomial logistic regression analysis with stepwise variable selection.CI Confidence interval, OR Odds ratio.Dependent variable: awareness of oral frailty (1: yes, 0: no).Independent variables entered the model were gender, age, residential area, diabetes mellitus, cerebrovascular disease, exercise habits, smoking habits, eating a balanced diet, consciousness of dental health, risk of oral frailty, and outpatient category.