Study design and participants
This was a cross-sectional study based on the survey on 34, 564 community-dwelling older adults aged ≥ 60 years in Iwamizawa, a regional city in Hokkaido, northern The japanese. This research included old adults who participated within wellness checkups in CHEER Iwamizawa ( a research project titled “Checkup to discover HEalth with Energy for senior Residents” in Iwamizawa) within October 2020. The individuals of BRIGHTEN Iwamizawa were recruited through a public relations magazine published by the town council and flyers posted at major public facilities in the city. In addition , local government employees visited older adults’ social clubs to describe the study’s purpose plus recruit participants. The survey content was explained verbally and in writing in order to the individuals, and written informed consent was obtained prior to the study. This study was conducted in accordance with the particular Declaration of Helsinki and approved by the Ethics Committee associated with the Faculty of Dental Medicine, Hokkaido University (approval number: 2020–9).
Evaluation of outcome
OHRQoL was evaluated using the Japanese version of the GOHAI 46 . The GOHAI consists of 12 questions rated on the five-point Likert scale assessing the frequency of dental health-related problems over the past three months. The total score ranges from twelve to 60; the higher the score, the higher the particular OHRQoL. The particular median scores, as per the GOHAI national norms for Japanese individuals, are 56. 0 plus 52. 5 for men aged 60 − 69 years and 70 − 79 years, respectively, and 54. 0 and 53. 0 for women older 60–69 many years and 70 − 79 years, correspondingly. Therefore , within this study, participants scoring below these cutoff values were defined as the poor OHRQoL group, while the remaining participants had been assigned in order to the good OHRQoL team.
Defining the risk of poor OHRQoL
CS plus LEH were defined as risk factors for bad OHRQoL, and their presence or absence was examined using self-administered questionnaires. CS was assessed from the question, “Do you feel stressed by the particular lifestyle changes plus restrictions upon going out due to the COVID-19 pandemic? ” (Yes/To some extent/Not really/No). Participants that answered either yes or to a few extent had been considered in order to have CS. LEH has been assessed simply by the query, “Do a person perform exercises, such because walking, at least once a week? ” (Yes/No). Participants who answered no were considered to lack exercise habits. Then, four mutually exclusive groups (risk of poor OHRQoL) had been created based on the presence or even absence of both CS and LEH (Group 1: no CS plus no LEH; Group 2: no CS and LEH; Group 3: CS and no LEH; Group 4: each CS and LEH).
Demographic characteristics
Data on participants’ age, sex, smoking status, body mass index, plus medical history (malignant neoplasm, stroke, myocardial infarction, depression, and osteoarthritis) were collected using a self-administered questionnaire.
Instrumental activities associated with daily living
IADL was evaluated using the JST-IC 38 . The JST-IC is made up of 16 questions with a “Yes/No” response format; the total score varies from 0 to sixteen. No specific cutoff value was set; higher ratings indicated increased IADL. The internal consistency acquired in the particular study population and example items of questionnaires are shown in Supplemental Table S4 (available online).
Assessment of depressive tendencies
The Japanese edition from the Geriatric Depression Scale short form (GDS-15) had been used to assess depressive habits. The GDS-15 comprises 15 questions in a “Yes/No” response format, with the total rating ranging from 0 to fifteen. In the present research, a total score of ≥ 6 indicated the presence of depressive tendencies 47 . The interior consistency obtained within the study population and example components of questionnaires are shown in Supplemental Table S4 (available online).
Number of teeth
The number of teeth erupted in the particular oral cavity was recorded, excluding stump teeth plus teeth with severe mobility.
Diagnosis of mouth hypofunction
Qualified examiners who else received two hours associated with instruction and training from the authors (K. M. and Y. W. ) regarding the appropriate data collection methods for measurements performed oral function dimensions. However, interexaminer reliability measures were not obtained. There was simply no strict calibration of examiners for dental function measurement. However, this potential nondifferential misclassification would probably bias results toward the particular null hypothesis and not really lead to overestimation of the observed associations. Significant robust associations were noticed under these types of circumstances. The particular oral function was objectively assessed using six of the seven parameters previously described to diagnose mouth hypofunction 48 : oral hygiene, oral moisture, occlusal force, tongue plus lip movement, tongue pressure, and masticatory function (excluding swallowing function). Oral hygiene was assessed using the tongue coating index 49 in order to determine the particular degree of tongue coating by visual inspection. Oral moisture was measured at the center from the language dorsum, approximately 10 mm from the apex of the tongue, using an oral moisture checker (Mucus, Life Co., Ltd., Saitama, Japan). Each measurement was taken thrice, and the median value was used. The occlusal pressure of the entire dentition was assessed utilizing a pressure-indicating film (Dental Prescale II, GC Corp, Tokyo, Japan) during 3 seconds associated with clenching within the intercuspal position. For denture users, the occlusal force has been measured with their dentures in place. Tongue plus lip movements were evaluated using oral diadochokinesis. Participants were asked to repeat the syllables /pa/, /ta/, and /ka/ for five seconds, and the number of each syllable pronounced per second had been counted making use of an automatic counter (Kenkoukun Handy, Takei Scientific Instruments Co., Limited., Niigata, Japan). Tongue pressure was scored thrice using a tongue stress measuring instrument (JMS language pressure measuring instrument, JMS Co., Ltd., Hiroshima, Japan), and the particular maximum worth was used. The masticatory function was measured using a masticatory ability testing system (Glucosensor GS-II, GC Corp., Tokyo, Japan).
Using previously established guidelines forty eight , the cutoff values for the above six items were as follows: tongue covering index ≥ 50%; dental moisture < 27. 0; occlusal force < 500 N; any of the /pa/, /ta/, or /ka/ syllables repeated < 6 times/second for diadochokinesis; tongue pressure < 30 kPa; and masticatory function < 100 mg/dL. Oral hypofunction has been defined when at least three from the 6 measurements met these criteria.
Sample size calculation
Sample size calculation was performed using G*Power 3. 1. 9. 7 50 . Assuming a two-tailed Mann–Whitney U test along with α = 0. 05 and d = 0. 50, an estimated 134 participants had been required to achieve a power of 0. 80.
Statistical analyses
Descriptive statistics, comparisons between the 2 groups with and without CS, and evaluations between two groups along with minus LEH were carried out by performing Mann–Whitney Oughout tests with regard to continuous variables as well as the chi-square test or Fisher’s exact test regarding categorical factors. The rating of categorical valuables is shown in Supplemental Desk S5 (available online). Comparisons among the 4 groups of risk factors intended for poor OHRQoL were made by carrying out the Kruskal–Wallis test to get continuous variables and the particular chi-square test or Fisher’s exact check for specific variables. Thereafter, Poisson regression with robust standard errors 51 was utilized to calculate the prevalence ratio pertaining to poor OHRQoL of CS alone and LEH alone, respectively. Adjustment factors included sociodemographic characteristics (i. e., age, sexual intercourse, body bulk index, JST-IC), depressive traits 27 , and the number associated with teeth 24 . Subsequently, the prevalence ratio for bad OHRQoL regarding the danger factors of poor OHRQoL was calculated. When the particular study design is similar to the present research, the odds ratio will be often attained by logistic regression analysis. However, within logistic regression analysis, the odds ratio is known to deviate from your true relative risk as the frequency of the outcome increases, overestimating chances ratio when the risk ratio is greater than 1. 0 and underestimating the chances ratio whenever the risk ratio is usually less than 1 . 0. 52 . Consequently , in this study, Poisson regression with strong standard errors was utilized to calculate estimates that approximate the true relative danger. All analyses were carried out using SPSS Statistics version 27 (IBM Corp., Armonk, NY, USA), as well as the significance level (two-tailed) was arranged at 5%. We followed the Strengthening the Reporting of Observational Studies within Epidemiology (STROBE) guidelines.