Faster surgery initiation in oral cancer patients during the COVID-19 pandemic in Osaka, Japan.

BACKGROUND: We investigated the impact of the COVID-19 pandemic on oral cancer (OC), comparing diagnosis and number of pre-operative days in the diagnosis of OC in 2019 (pre-COVID-19) and that in 2020 (during the COVID-19 pandemic). METHODS: Using data from a cancer registry-based study on the impact of COVID-19 on cancer care in Osaka (CanReCO), we collected details of sex, age, residential area, cancer site, date of diagnosis, clinical stage at first treatment and number of pre-operative days in OC patients. RESULTS: A total of 1470 OC cases were registered. Incidence of OC before and during COVID-19 was 814 and 656 cases, respectively. During the first wave of the pandemic (March to May 2020), incidence was about half that in the same period in 2019 (2019; n = 271, 2020; n = 145). Number of pre-operative days (median number of days between the first hospital visit and surgery date) was significantly shorter during the COVID-19 year (24.5 days) than in the pre-COVID-19 year (28 days, p = 0.0015). CONCLUSIONS: Incidence of OC during the COVID-19 pandemic was lower than in pre-COVID-19. Despite disruption in the healthcare system, the number of pre-operative days for OC cases was shorter during the pandemic.

Surgical volume threshold to improve 3-year survival in designated cancer care hospitals in 2004-2012 in Japan.

In Japan, cancer care hospitals designated by the national government have a surgical volume requirement of 400 annually, which is not necessarily defined based on patient outcomes. This study aimed to estimate surgical volume thresholds that ensure optimal 3-year survival for three periods. In total, 186 965 patients who had undergone surgery for solid cancers in 66 designated cancer care hospitals in Osaka between 2004 and 2012 were examined using data from a population-based cancer registry. These hospitals were categorized by the annual surgical volume of each 50 surgeries (eg, 0-49, 50-99, and so on). Using multivariable Cox proportional hazard regression, we estimated the adjusted 3-year survival probability per surgical volume category for 2004-2006, 2007-2009, and 2010-2012. Using the joinpoint regression model that computes inflection points in a linear relationship, we estimated the points at which the trend of the association between surgical volume and survival probability changes, defining them as surgical volume thresholds. The adjusted 3-year survival ranges were 71.7%-90.0%, 68.2%-90.0%, and 79.2%-90.3% in 2004-2006, 2007-2009, and 2010-2012, respectively. The surgical volume thresholds were identified at 100-149 in 2004-2006 and 2007-2009 and 200-249 in 2010-2012. The extents of change in the adjusted 3-year survival probability per increase of 50 surgical volumes were +4.00%, +6.88%, and +1.79% points until the threshold and +0.41%, +0.30%, and +0.11% points after the threshold in 2004-2006, 2007-2009, and 2010-2012, respectively. The existing surgical volume requirements met our estimated thresholds. Surgical volume thresholds based on the association with patient survival may be used as a reference to validate the surgical volume requirement.

Three-year survival from diagnosis in surgically treated patients in designated and nondesignated cancer care hospitals in Japan.

The Japanese national and prefectural governments have accredited high-capacity, high-experience cancer care hospitals as "designated cancer care hospitals" to standardize cancer care, centralize patients, and improve clinical outcomes, but the performance of these designated hospitals has not been evaluated. We retrospectively compared 3-year patient survival in national, prefectural, and nondesignated cancer care hospitals in 2010-2012 in Osaka using registry-based data of 86 456 surgically treated cancer patients aged 15 years or older. Hazard ratios and 3-year survival probabilities were compared among national, prefectural, and nondesignated hospitals using a Cox proportional hazard regression model. Subgroup analyses for six cancers (stomach, colorectum, lung, breast, uterus, and prostate) and other cancers were carried out. In 2010-2012, 36 634 (42.4%), 38 048 (44.0%), and 11 774 (13.6%) patients were treated at national, prefectural, and nondesignated hospitals, respectively. The mortality hazard for all-site cancer was significantly lower in national and prefectural designated hospitals (adjusted hazard ratio 0.60 [95% confidence interval, 0.53-0.68] and 0.72 [0.66-0.80], respectively) than in nondesignated hospitals. The adjusted 3-year survival probabilities for all-site cancer were 86.6%, 84.2%, and 78.8% in national, prefectural, and nondesignated hospitals, respectively. Site-specific subgroup analyses revealed significantly lower hazard ratios in national and prefectural hospitals than in nondesignated hospitals for stomach, colorectal, lung, breast, and other cancers. To conclude, the majority of cancer patients underwent surgeries at designated hospitals and had higher 3-year survival probabilities than those treated at nondesignated hospitals. Further centralization of patients from nondesignated to designated hospitals could improve population-level survival.

Hospital volume and 5-year survival in head and neck cancer patients in Osaka, Japan.

BACKGROUND: Few previous studies have examined the relationship between hospital volume and hazard of death for head and neck cancer patients. The purpose of this study was to examine the association between hospital volume and 5-year survival from diagnosis among head and neck cancer patients. METHODS: Using data from the population-based Osaka Cancer Registry, hospital volume was divided into three volume groups according to the number of head and neck cancer treatments identified between 2009 and 2011. We analysed the association between hospital volume and 5-year survival among 3069 patients aged 0-79 using Cox proportional hazard models, adjusting for characteristics of patients. RESULTS: Compared with head and neck cancer patients in high-hospital volume, patients treated in middle- and low-hospital volume were found to have a higher risk of death (middle-hospital volume: hazard ratio = 1.26; 95% confidence interval, 1.09-1.46, low-hospital volume: hazard ratio = 1.24; 95% confidence interval, 1.06-1.46). CONCLUSIONS: We found a significantly higher risk of hazard of death in middle- and low-hospital volume than in high-hospital volume for head and neck cancer.

Changes in Smoking Behavior Since the Declaration of the COVID-19 State of Emergency in Japan: A Cross-sectional Study From the Osaka Health App.

BACKGROUND: In April 2020, the Japanese government declared a state of emergency due to the COVID-19 pandemic, and infection control measures, including requests to work from home and stay-at-home restrictions, were introduced. This study examined changes in smoking behavior during the COVID-19 state of emergency. METHODS: An online cross-sectional survey was conducted in Osaka, Japan. To assess differences in smoking behavior among 5,120 current smokers before and after the declaration of a state of emergency, prevalence ratios (PRs) for two outcomes, increased smoking and quitting smoking, were calculated using multivariable Poisson regression, adjusting for potential covariates. RESULTS: We found 32.1% increased the number of cigarettes smoked and 11.9% quit smoking. After adjustment for all variables, we found risk factors for COVID-19 (men and older age group) had both significantly higher PR for quitting smoking (men: PR 1.38; 95% confidence interval [CI], 1.17-1.62) and participants aged ≥65 years: PR 2.45; 95% CI, 1.92-3.12) and significantly lower PR of increased smoking (men: PR 0.85; 95% CI, 0.78-0.93 and participants ≥65 years: PR 0.38; 95% CI, 0.29-0.49). Additionally, respondents working from home or living alone had significantly higher PR for increased smoking (working from home: PR 1.29; 95% CI, 1.17-1.41 and living alone: PR 1.23; 95% CI, 1.10-1.38) and respondents who changed from cigarettes to heated tobacco products (HTPs) had significantly lower PR for quitting smoking (PR 0.150; 95% CI, 0.039-0.582). CONCLUSIONS: We suggest people who have high-risk factors for COVID-19 might change their smoking behavior for the better, while people who work from home or live alone might change their smoking behavior for the worse, during the COVID-19 state of emergency. Additionally, changing from smoking cigarettes to using HTPs makes smokers less likely to quit.

Hospital Surgical Volume and 3-Year Mortality in Severe Prognosis Cancers: A Population-Based Study Using Cancer Registry Data.

BACKGROUND: The impact of hospital surgical volume on long-term mortality has not been well assessed in Japan, especially for esophageal, biliary tract, and pancreatic cancer, although these three cancers need a high level of medical-technical skill. The purpose of this study was to examine associations between hospital surgical volume and 3-year mortality for these severe-prognosis cancer patients. METHODS: Patients who received curative surgery for esophageal, biliary tract, and pancreatic cancers were analyzed using the Osaka Cancer Registry data from 2006-2013. Hospital surgical volume was categorized into tertiles (high/middle/low) according to the average annual number of curative surgeries per hospital for each cancer. Three-year survivals were calculated using the Kaplan-Meier method. Hazard ratios (HRs) of 3-year mortality were calculated using Cox proportional hazard models, adjusting for patient characteristics. RESULTS: Three-year survival was higher with increased hospital surgical volume for all three cancers, but the relative importance of volume varied across sites. After adjustment for all confounding factors, HRs in middle- and low-volume hospitals were 1.34 (95% confidence interval [CI], 1.14-1.58) and 1.57 (95% CI, 1.33-1.86) for esophageal cancer; 1.39 (95% CI, 1.15-1.67) and 1.57 (95% CI, 1.30-1.89) for biliary tract cancer; 1.38 (95% CI, 1.16-1.63) and 1.90 (95% CI, 1.60-2.25) for pancreatic cancer, respectively. In particular for localized pancreatic cancer, the impact of hospital surgical volume on 3-year mortality was strong (HR 2.66; 95% CI, 1.61-4.38). CONCLUSION: We suggest that patients who require curative surgery for esophageal, biliary tract, and pancreatic cancer may benefit from referral to high-volume hospitals.

Association Between Social Isolation and Smoking in Japan and England.

BACKGROUND: Existing evidence suggest that those who are socially isolated are at risk for taking up or continuing smoking. This study investigated country-based differences in social isolation and smoking status. METHODS: We performed a repeated cross-sectional study using two waves of data from two ongoing aging studies: the English Longitudinal Study of Ageing and the Japan Gerontological Evaluation Study. Participants from both studies aged ≥65 years were included. We applied a multilevel Poisson regression model to examine the association between social isolation and smoking status and adjusted for individual sociodemographic characteristics. We used the social isolation index which comprises the following domains: marital status; frequency of contact with friends, family, and children; and participation in social activities. Interaction terms between each country and social isolation were also entered into the mode. RESULTS: After exclusion of never smokers, we analyzed 75,905 participants (7,092 for ELSA and 68,813 for JAGES, respectively). Taking ex-smokers as the reference, social isolation was significantly associated with current smoking; the prevalence ratios (PRs) were 1.06 (95% credible interval [CrI], 1.05-1.08) for men and 1.08 (95% CrI, 1.04-1.11) for women. Taking Japan as a reference, the interaction term between country and social isolation was significant for both sexes, with increased PRs of 1.32 (95% CrI, 1.14-1.50) for men and 1.30 (95% CrI, 1.11-1.49) for women in England. CONCLUSIONS: Older people who were less socially isolated were more likely to quit smoking in England than in Japan, possibly explained by the strict tobacco control policies in England.

Hospital volume and postoperative survival for three urological cancers: Prostate, kidney, and bladder.

OBJECTIVE: To examine the association between hospital volume and postoperative 5-year survival for patients with prostate, kidney, and bladder cancer. METHOD: Using Osaka Cancer Registry data, we identified 9285 patients who were diagnosed as having prostate, kidney, or bladder cancer and who underwent surgery between 2007 and 2011 in Osaka, Japan. The surgical hospital volume of each hospital was calculated and then divided into quartiles (high, medium, low, very low). We estimated the hazard ratios of hospital volume (quartiles) for 5-year survival using Cox proportional hazard models. RESULTS: For all three cancer sites, the mortality hazard of hospitals with the lowest hospital volume was significantly higher than that of hospitals with the highest volume. The difference in adjusted 5-year survival rates between hospitals with the highest and lowest hospital volume was 3.6% for prostate cancer, 6.6% for kidney cancer, and 13.3% for bladder cancer. CONCLUSION: Hospital surgical volume seems to affect 5-year survival for patients with urological cancers, especially kidney and bladder cancer.

Hospital volume and postoperative 5-year survival for five different cancer sites: A population-based study in Japan.

The relationship between hospital volume and patient outcome is globally known; thus, hospital volume is widely used as a quality indicator. In Japan, however, recent studies on this topic are scarce. The present study examined whether hospital surgery volume is associated with postoperative 5-year survival among cancer patients. Using the Osaka Cancer Registry, we identified a sample of 86 145 patients who were diagnosed with cancer at any of five different sites (stomach, colorectum, lung, breast and uterus) and underwent surgeries between 2007 and 2011 in Osaka. We ranked hospitals by annual surgical volume, sorted patients in descending order by hospital volume, and assigned them into quartiles (high, medium, low and very low volume). We analyzed the association between hospital volume and 5-year survival among 80 959 patients aged between 15 and 84 years using Cox proportional hazard models. Adjustments were made for characteristics of patients, type of surgery and adjuvant treatment received. The mortality hazard of patients treated at very low-volume hospitals was 1.36-1.82-fold higher than that of patients treated at high-volume hospitals. Absolute differences in adjusted survival rates between high-volume and very low-volume hospitals varied with the cancer site: 14.9 in stomach, 11.5 in colorectal, 10.8 in lung, 2.4 in breast and 3.3 in uterine cancers. Hospitals with lower surgery volumes showed higher mortality risks after cancer surgery than those with higher volumes. Monitoring site-specific surgery volumes and referring patients from low-volume to high-volume hospitals may be beneficial for improving the long-term survival of cancer patients.

Design and Progress of Oral Health Examinations in the Tohoku Medical Megabank Project.

In order to assess the long-term impact of the Great East Japan Earthquake on the oral health of disaster victims and to evaluate gene-environmental interactions in the development of major oral diseases and oral-systemic associations, the oral part of two large-scale genome cohort studies by the Tohoku Medical Megabank Organization (ToMMo), including the Community-based cohort (CommCohort) study and the Birth and Three-Generation cohort (BirThree) study, have been conducted. The study population comprised 32,185 subjects, including 16,886 participants in the CommCohort study and 15,299 participants in the BirThree cohort study, recruited from 2013 to 2017. The oral studies consist of a questionnaire regarding oral hygiene behavior, clinical examinations by dentists, and oral plaque and saliva sampling for microbiome analyses, which were carried out at seven community support centers in Miyagi prefecture. The median age of all participants was 55.0 years, and 66.1% of participants were women. Almost all participants reported that they brushed their teeth more than once a day. The median number of present teeth was 27.0, and the decayed, missing and filled tooth number was 16.0, with a significant difference according to age and sex. The median periodontal pocket and clinical attachment level was 2.48 mm and 4.00 mm, respectively. Periodontal parameters increased significantly according to age, except for the accumulation of dental calculus. The oral part of these extensive cross-sectional studies provides a unique and important platform for future studies on oral health and diseases that elicit through interactions with systemic diseases, lifestyles, life events and genetic backgrounds, and contributes to researches clarifying the long-term effects of disasters on oral health.

Does Cigarette Smoking Increase Traffic Accident Death During 20 Years Follow-up in Japan? The Ibaraki Prefectural Health Study.

BACKGROUND: Annually, more than 1.2 million deaths due to road traffic accidents occur worldwide. Although previous studies have examined the association between cigarette smoking and injury death, the mortality outcome often included non-traffic accident-related deaths. This study aimed to examine the association between cigarette smoking and traffic accident death. METHODS: We conducted a prospective cohort study using data from the Ibaraki Prefectural Health Study conducted from 1993 through 2013. The cohort included 97,078 adults (33,138 men and 63,940 women) living in Ibaraki Prefecture who were aged 40-79 years at an annual health checkup in 1993. We divided participants into four smoking status groups: non-smokers, ex-smokers, and current smokers who smoked <20 and ≥20 cigarettes per day. Hazard ratios (HRs) of traffic accident death were calculated using a Cox proportional hazards model. RESULTS: During 20 years of follow-up, the average person-years of follow-up were 16.8 and 18.2 in men and women, respectively. Among men, after adjusting for age and alcohol intake, HRs for traffic accident death among current smokers of <20 cigarettes/day and ≥20 cigarettes/day compared to non-smokers were 1.32 (95% confidence interval [CI], 0.79-2.20) and 1.54 (95% CI, 0.99-2.39), respectively. In contrast, among women, we found no association between smoking status and traffic accident deaths. CONCLUSION: In this prospective cohort study, we found a positive association, though marginally significant, between smoking and traffic accident death among men in Japan. Among women, because of the smaller number of deaths among smokers, adequate estimation could not be obtained.

Does the Type of Temporary Housing Make a Difference in Social Participation and Health for Evacuees of the Great East Japan Earthquake and Tsunami? A Cross-Sectional Study.

BACKGROUND: Although the majority of survivors of the huge Great East Japan Earthquake and Tsunami evacuated to two types of temporary housings, prefabricated housing and rented housing, health effects of these different environments were unclear. We examined whether prevalent social participation in prefabricated housing brought larger health benefits than in rented housing using the largest health survey data of the disaster survivors. METHODS: This cross-sectional study used a 2012 survey by the Miyagi Prefectural Government, in which almost all of evacuees were targeted (response rate: 61.6%). Self-rated health (SRH) and psychological distress measured via K6 score were the dependent variables, and social participation was the independent variable. Odds ratios of the social participation on health variables were estimated using logistic regression models. To assess the contribution of social participation, the population attributable fraction (PAF) was estimated. RESULTS: The participants lived in prefabricated and rented housing numbered 19,726 and 28,270, respectively. Participants in prefabricated housing had poorer SRH and K6 than those in rented housing. The proportions of participants engaging in social participation of prefabricated and rented housing were 38.2% and 15.4%, respectively. The absence of social participation was significantly associated with poor SRH and K6 among participants in both housing types. The PAFs of social participation with good SRH were 39.5% in prefabricated housing and 14.4% in rented housing. For K6, the PAFs were 47.1% and 19.5% in prefabricated and rented housing, respectively. CONCLUSION: Compared to the residents in rented housing, residents in prefabricated housing had more frequent opportunities for social participation, which was associated with larger health benefits.

Income and education are associated with transitions in health status among community-dwelling older people in Japan: the JAGES cohort study.

BACKGROUND: Health inequalities are an emerging issue in ageing societies, but inequalities in pre-frailty, which is suffered by almost half of older people, are mostly unknown. OBJECTIVE: This study aimed to determine the association between the socio-economic status (SES) and changes across pre-frailty, frailty, disability and all-cause mortality. METHODS: We conducted a prospective cohort study across 23 Japanese municipalities between 2010 and 2013. Functionally independent community-dwelling older adults aged ≥65 years (n = 65 952) in 2010 were eligible for the study. The baseline survey was conducted from 2010 to 2012, and the self-reporting questionnaires were mailed to 126 438 community-dwelling older adults [64.8% (81 980/126 438) response rate]. The follow-up survey was conducted in 2013. Overall, 65 952 individuals were followed up [80.4% (65 952/81 980) follow-up rate]. The health status was classified into five groups: robust; pre-frailty; frailty; disability and death. We conducted three multinomial logistic regression models stratified by the initial disability status. Educational attainment and equivalized household income were separately added to the models as exposures after adjusting for covariates. RESULTS: Participants with the lowest educational level were less likely to recover from pre-frailty to robust compared with those with the highest level [odds ratio (OR) (95% confidence interval (CI)) = 0.84 (0.76-0.93)]. The participants with the lowest income level were also less likely to recover from pre-frailty to robust compared with those with the highest level [OR (95% CI) = 0.80 (0.69-0.91)]. CONCLUSIONS: Older individuals with a lower SES were less likely to recover from a pre-frailty status.

Does Type of Residential Housing Matter for Depressive Symptoms in the Aftermath of a Disaster? Insights From the Great East Japan Earthquake and Tsunami.

The 2011 Great East Japan Earthquake and Tsunami resulted in widespread property destruction and over 250,000 displaced residents. We sought to examine whether the type of housing arrangement available to the affected victims was associated with a differential incidence of depressive symptoms. In this prospective cohort study, which comprised participants aged ≥65 years from Iwanuma as a part of the Japan Gerontological Evaluation Study, we had information about the residents' mental health both before the disaster in 2010 and 2.5 years afterward. The Geriatric Depression Scale was used. Type of accommodation after the disaster was divided into 5 categories: no move, prefabricated housing (temporary housing), existing private accommodations (temporary apartment), newly established housing, and other. Poisson regression analysis was adopted, with and without multiple imputation. Among the 2,242 participants, 16.2% reported depressive symptoms at follow-up. The adjusted rate ratio for depressive symptoms among persons moving into prefabricated housing, compared with those who did not, was 2.07 (95% confidence interval: 1.45, 2.94). Moving into existing private accommodations or other types of accommodations was not associated with depression. The relationship between living environment and long-term mental health should be considered for disaster recovery planning.

Social Inequalities in Secondhand Smoke Among Japanese Non-smokers: A Cross-Sectional Study.

BACKGROUND: Secondhand smoke (SHS) causes many deaths. Inequalities in SHS have been reported in several countries; however, the evidence in Asian countries is scarce. We aimed to investigate the association between socioeconomic status (SES) and SHS at home and the workplace/school among non-smoking Japanese adults. METHODS: Cross-sectional data from the Miyagi Prefectural Health Survey 2014 were analyzed. Self-reported questionnaires were randomly distributed to residents ≥20 years of age and 2,443 (92.8%) responded. The data of the 1,738 and 1,003 respondents were included to the analyses for SHS in the past month at home and at the workplace/school, respectively. Ordered logistic regression models considering possible confounders, including knowledge of the adverse health effects of tobacco, were applied. RESULTS: The prevalence of SHS at home and the workplace/school was 19.0% and 39.0%, respectively. Compared with ≥13 years of education, odds ratios (ORs) and 95% confidence intervals (CIs) for SHS at home were 1.94 (95% CI, 1.42-2.64) for 10-12 years and 3.00 (95% CI, 1.95-4.60) for ≤9 years; those for SHS at the workplace/school were 1.80 (95% CI, 1.36-2.39) and 3.82 (95% CI, 2.29-6.36), respectively. Knowledge of the adverse health effects of tobacco was significantly associated with lower SHS at home (OR 0.95; 95% CI, 0.91-0.98) but it was not associated with SHS at the workplace/school (OR 1.02; 95% CI, 0.98-1.06). CONCLUSIONS: Social inequalities in SHS existed among Japanese non-smoking adults. Knowledge about tobacco was negatively associated with SHS at home but not at workplace/school.

Development of an instrument for community-level health related social capital among Japanese older people: The JAGES Project.

BACKGROUND: We developed and validated an instrument to measure community-level social capital based on data derived from older community dwellers in Japan. METHODS: We used cross-sectional data from the Japan Gerontological Evaluation Study, a nationwide survey involving 123,760 functionally independent older people nested within 702 communities (i.e., school districts). We conducted exploratory and confirmatory factor analyses on survey items to determine the items in a multi-dimensional scale to measure community social capital. Internal consistency was checked with Cronbach's alpha. Convergent construct validity was assessed via correlating the scale with health outcomes. RESULTS: From 53 candidate variables, 11 community-level variables were extracted: participation in volunteer groups, sports groups, hobby activities, study or cultural groups, and activities for teaching specific skills; trust, norms of reciprocity, and attachment to one's community; received emotional support; provided emotional support; and received instrumental support. Using factor analysis, these variables were determined to belong to three sub-scales: civic participation (eigenvalue = 3.317, α = 0.797), social cohesion (eigenvalue = 2.633, α = 0.853), and reciprocity (eigenvalue = 1.424, α = 0.732). Confirmatory factor analysis indicated the goodness of fit of this model. Multilevel Poisson regression analysis revealed that civic participation score was robustly associated with individual subjective health (Self-Rated Health: prevalence ratio [PR] 0.96; 95% confidence interval [CI], 0.94-0.98; Geriatric Depression Scale [GDS]: PR 0.95; 95% CI, 0.93-0.97). Reciprocity score was also associated with individual GDS (PR 0.98; 95% CI, 0.96-1.00). Social cohesion score was not consistently associated with individual health indicators. CONCLUSIONS: Our scale for measuring social capital at the community level might be useful for future studies of older community dwellers.

School-Based Fluoride Mouth-Rinse Program Dissemination Associated With Decreasing Dental Caries Inequalities Between Japanese Prefectures: An Ecological Study.

BACKGROUND: Dental caries inequalities still severely burden individuals' and society's health, even in countries where fluoride toothpastes are widely used and the incidence of dental caries has been decreasing. School-based fluoride mouth-rinse (S-FMR) programs, a population strategy for dental caries prevention, might decrease dental caries inequalities. This study investigated the association between S-FMR and decreasing dental caries prevalence and caries-related inequalities in 12-year-olds by Japanese prefecture. METHODS: We conducted an ecological study using multi-year prefecture-level aggregated data of children born between 1994 and 2000 in all 47 Japanese prefectures. Using two-level linear regression analyses (birth year nested within prefecture), the association between S-FMR utilization in each prefecture and 12-year-olds' decayed, missing, or filled permanent teeth (DMFT), which indicates dental caries experience in their permanent teeth, were examined. Variables that could explain DMFT inequalities between prefectures, such as dental caries experience at age 3 years, dentist density, and prefectural socioeconomic circumstances, were also considered. RESULTS: High S-FMR utilization was significantly associated with low DMFT at age 12 (coefficient -0.011; 95% confidence interval, -0.018 to -0.005). S-FMR utilization explained 25.2% of the DMFT variance between prefectures after considering other variables. Interaction between S-FMR and dental caries experience at age 3 years showed that S-FMR was significantly more effective in prefectures where the 3-year-olds had high levels of dental caries experience. CONCLUSIONS: S-FMR, administered to children of all socioeconomic statuses, was associated with lower DMFT. Utilization of S-FMR reduced dental caries inequalities via proportionate universalism.

Does poor dental health predict becoming homebound among older Japanese?

BACKGROUND: Being homebound is an important risk factor of functional disability in older people. There is a possibility of bidirectional relationship between homeboundness and dental health. This prospective cohort study examined the association of dental health, which includes social function, on homeboundness in the future. METHODS: The participants were ≥ 65 years, responded to two postal surveys conducted in 2006 and 2010, and were not homebound at baseline. Logistic regression analysis was used to estimate the odds ratios for homeboundness, defined as going out of one's home less than once weekly. Self-reported baseline dental status was used as the main predictor. Age, sex, marital status, educational attainment, income, comorbidity, depression, walking time, living alone, and area of residence were used as covariates. RESULTS: Among 4390 non-homebound respondents, 7.4 % were homebound four years later. The proportions of homebound respondents with < 20 teeth without dentures, < 20 teeth with dentures, and ≥ 20 teeth were 9.7, 8.8, and 4.4 %, respectively. The odds for being homebound in the 65-74-year age group, adjusted for covariates, was 1.78 (95 % CI: 1.01-3.13; p < 0.05) times higher for respondents with < 20 teeth and no dentures than that for respondents with ≥ 20 teeth. Among the participants in the ≥ 75-year age group, a significant association of homeboundness and dental health was not observed. CONCLUSIONS: Among the young-old population, poor dental health predicted future onset of homeboundness, while depressive symptoms did not show any significant association.

Impact of loss of removable dentures on oral health after the great East Japan earthquake: a retrospective cohort study.

PURPOSE: The Great East Japan Earthquake in March 2011 destroyed many communities, and as a result many older victims lost their removable dentures. No previous studies have documented the prevalence of denture loss after a natural disaster or examined its negative impact. Therefore, investigation of the consequences of such a disaster on oral health is of major importance from a public health viewpoint. MATERIALS AND METHODS: Three to five months after the disaster, questionnaire surveys were conducted in two coastal towns, Ogatu and Oshika, located in the area of Ishinomaki city, Miyagi prefecture. Among the survey participants, 715 individuals had used one or more removable dentures before the disaster, and these comprised the population analyzed. The effect of denture loss on oral health-related quality life (OHRQoL) was examined by a modified Poisson regression approach with adjustment for sex, age, subjective household economic status, dental caries, tooth mobility, psychological distress (K6), access to a dental clinic, physical activity, and town of residence. RESULTS: There were 123 (17.2%) participants who had lost their dentures. In comparison with participants who had not lost their dentures, those lacking dentures showed a significantly higher relative risk for eating difficulties (RR = 2.65, 95%CI = 1.90-3.69), speech problems (RR = 4.37, 95%CI = 2.46-7.76), embarrassment upon smiling, laughing, or showing their teeth (RR = 5.32, 95%CI = 2.34-12.1), emotional distress (RR = 2.38, 95%CI = 1.41-4.03), and problems related to social interaction (RR = 6.97, 95%CI = 1.75-27.7). CONCLUSIONS: Denture loss appeared to impair eating and speaking ability, thus discouraging communication with others. Public health intervention after major natural disasters should include dental care.