A genome-wide association study identifies a locus associated with knee extension strength in older Japanese individuals.

Sarcopenia is a common skeletal muscle disease in older people. Lower limb muscle strength is a good predictive value for sarcopenia; however, little is known about its genetic components. Here, we conducted a genome-wide association study (GWAS) for knee extension strength in a total of 3452 Japanese aged 60 years or older from two independent cohorts. We identified a significant locus, rs10749438 which is an intronic variant in TACC2 (transforming acidic coiled-coil-containing 2) (P = 4.2 × 10-8). TACC2, encoding a cytoskeleton-related protein, is highly expressed in skeletal muscle, and is reported as a target of myotonic dystrophy 1-associated splicing alterations. These suggest that changes in TACC2 expression are associated with variations in muscle strength in older people. The association was consistently observed in young and middle-aged subjects. Our findings would shed light on genetic components of lower limb muscle strength and indicate TACC2 as a potential therapeutic target for sarcopenia.

Combined association of oral and skeletal muscle health with type 2 diabetes mellitus among community-dwelling older adults in Japan: a cross-sectional study.

Objective: Although oral health and skeletal muscle status are known to be risk factors for type 2 diabetes mellitus (T2DM), there is limited information on their combined effects among community-dwelling older adults. The purpose of this study was to investigate the association between oral health and skeletal muscle status among older adults with T2DM in Japan. Participants and Methods: This cross-sectional study included data from individuals aged ≥60 years. T2DM was defined as a glycosylated hemoglobin A1c level ≥48 mmol/mol (≥6.5%) or the use of hypoglycemic agents. For oral health status, dental hygienists assessed the number of teeth (NT) and masticatory function (MF). Skeletal muscle status was assessed using skeletal muscle mass index (SMI) and handgrip strength (HGS). Logistic regression analysis examined T2DM in nine-category combinations of oral health status (each of the three categories in NT and MF) and skeletal status (each of the three categories in SMI and HGS). Results: T2DM was prevalent in 83 participants (16.4%) and was significantly associated with low NT and SMI (odds ratio [OR] = 5.93, 95% confidence interval [CI]: 1.37-25.73) and low MF and SMI (OR = 4.48, 95% CI: 1.23-16.35) compared to high NT and SMI and high MF and SMI, respectively. Conclusion: Our findings indicate that low muscle mass with tooth loss or masticatory dysfunction is associated with T2DM among community-dwelling older adults. This suggests that maintaining oral health and muscle mass may be an effective strategy for the prevention of T2DM.

Relationship between Masticatory Function and Bone Mineral Density in Community-Dwelling Elderly: A Cross-Sectional Study.

The relationship between masticatory function and bone mineral density (BMD) is unclear. This cross-sectional study examined this relationship after adjusting for confounding factors. The subjects were 702 community-dwelling elderly adults (306 men, 396 women) who had been recruited for the Community-Based Healthcare Research and Education study in 2019. Objective masticatory function was assessed using the gummy jelly method. The median for each descriptive statistic was 69.0 years for age, 86.2% for the young adult mean, and 18.0 for masticatory function. Comparisons of the groups with good and poor masticatory function by sex revealed a significant difference in muscle mass and the tooth number for both sexes (p < 0.05). Men showed significant differences in age (p < 0.05) and salivary occult blood findings (p < 0.05). Multivariate analysis using propensity scores showed a significant association between masticatory function and BMD in both sexes (men: odds ratio 163.0, 95% confidence interval 1.36-19,610.55, p = 0.04; women: odds ratio 48.65, 95% confidence interval 1.52-1561.15, p = 0.03 in women). Masticatory function and BMD in the community-dwelling elderly may be related. However, other factors, including frailty and sarcopenia, may also be involved. Regular oral health care by dentists and dental hygienists may benefit this population.

Effect of Multimorbidity on Fragility Fractures in Community-Dwelling Older Adults: Shimane CoHRE Study.

Fragility fractures (FFxs), which are a common musculoskeletal injury in older adults, is associated with an increased frequency of falls. Both FFxs and falls may result from drugs, habits, and co-occurring diseases. We aimed to evaluate the effects of various diseases on the risk of FFx. This retrospective study included 1420 individuals aged ≥60 years. We evaluated the history of clinical FFx and diseases using a detailed questionnaire and a health examination. The risk of comorbidities was assessed using the Age-Adjusted Charlson Comorbidity (AAC) Index. We performed binary logistic regression analysis to determine the risk of FFx and falls after adjusting for covariates. In elderly men, the incidence of FFx positively correlated with rheumatoid arthritis and parent's hip fracture. For elderly women, the incidence of FFx positively correlated with rheumatoid arthritis and antihypertensive drugs but was inversely associated with dyslipidemia and antilipidemic drugs. The FFX risk of older adults with an AAC Index ≥6 was higher than those with an AAC Index of 1-3. In addition, the AAC Index and falls were independently and strongly associated with a higher risk of FFx. Taken together, multimorbidity increases the risk of clinical FFx independent of falls in the community-dwelling elderly population.

An association analysis between hypertension, dementia, and depression and the phases of pre-sarcopenia to sarcopenia: A cross-sectional analysis.

Sarcopenia is intricately related to aging associated diseases, such as neuropsychiatric disorders, oral status, and chronic diseases. Dementia and depression are interconnected and also related to sarcopenia. The preliminary shift from robust to sarcopenia (i.e., pre-sarcopenia) is an important albeit underdiscussed stage and is the focus of this study. Identifying factors associated with pre-sarcopenia may lead to sarcopenia prevention. To separately examine the effects of dementia and depression on pre-sarcopenia/sarcopenia, we conducted multiple analyses. This cross-sectional study used health checkup data from a rural Japanese island. The participants were aged 60 years and above, and the data included muscle mass, gait speed, handgrip strength, oral status (teeth and denture), chronic diseases (e.g., hypertension), dementia (cognitive assessment for dementia, iPad Version), and depression (self-rating depression scale). A total of 753 older adult participants were divided into the sarcopenia (n = 30), pre-sarcopenia (n = 125), and robust (n = 598) groups. An ordered logit regression analysis indicated that age and depression were positively correlated with sarcopenia, while hypertension was negatively associated with it. A multiple logistic regression analysis between the robust and pre-sarcopenia groups showed significant associations between the same three variables. Depression was associated with pre-sarcopenia, but not dementia. There was also a significant association between hypertension and pre-sarcopenia. Further research is needed to reveal whether the management of these factors can prevent sarcopenia.

Number of teeth and masticatory function are associated with sarcopenia and diabetes mellitus status among community-dwelling older adults: A Shimane CoHRE study.

OBJECTIVES: We aimed to examine the number of teeth and masticatory function as oral health indices and clarify their roles in the pathogenesis of sarcopenia and diabetes mellitus in community-dwelling older adults. SUBJECTS AND METHODS: This cross-sectional study was conducted with 635 older adults in Ohnan, Shimane Prefecture, in rural Japan. The number of teeth and masticatory function (measured by the number of gummy jelly pieces collected after chewing) were evaluated by dental hygienists. Sarcopenia status was assessed using handgrip strength, skeletal muscle index, calf circumference, and a possible sarcopenia diagnosis based on the Asian Working Group for Sarcopenia 2019. Diabetes mellitus status was defined as a hemoglobin A1c level ≥6.5% or self-reported diabetes. A multivariable logistic regression model was used to analyze the association between oral health, sarcopenia, and diabetes mellitus after adjusting for confounders. RESULTS: After adjusting for all confounders, logistic regression analysis showed that the number of remaining teeth was negatively associated with a low level of handgrip strength (odds ratio [OR], 0.961; 95% confidence interval [CI], 0.932-0.992) and possible sarcopenia (OR, 0.949; 95% CI, 0.907-0.992). Higher levels of masticatory function were also negatively associated with a low level of handgrip strength (OR, 0.965; 95% CI, 0.941-0.990) and possible sarcopenia (OR, 0.941; 95% CI, 0.904-0.979). Logistic regression analysis showed that the number of remaining teeth and a higher level of masticatory function were negatively associated with diabetes mellitus (OR, 0.978; 95% CI, 0.957-0.999; OR, 0.976; 95% CI, 0.960-0.992, respectively). CONCLUSION: Our findings suggest that improvement in oral health, including the maintenance of masticatory function and remaining teeth, may contribute to the prevention of sarcopenia and diabetes mellitus in older adults.

Relationship between Oral Health Status and Bone Mineral Density in Community-Dwelling Elderly Individuals: A Cross-Sectional Study.

The relationship between oral health status and bone mineral density has been poorly elucidated. We conducted a cross-sectional study to examine the relationship between oral health status and bone mineral density with data from healthy community-dwelling elderly individuals in Ohnan-cho, Shimane Japan who were recruited in 2019 for the Shimane Center for Community-Based Health Research and Education (CoHRE) study. The study included 702 participants (306 men and 396 women). The median age, bone mineral density, and number of remaining teeth were 69.0 years, 86.2%, and 26.0, respectively. The two groups (Low teeth group and High teeth group) showed significant differences in age, hemoglobin A1c (HbA1c) level, and masticatory function in men (p < 0.05). In women, age, number of untreated teeth, and masticatory function were significantly different (p < 0.05). The odds ratio of propensity score analysis for the association between the number of remaining teeth and bone mineral density was 27.7 (95% confidence interval: 1.86-414.9, p < 0.05). The number of remaining teeth could be associated with bone mineral density in the healthy elderly women, and no significant association was observed in men. Number of remaining teeth and bone mineral density may be interrelated, and oral care by dentists/dental hygienists may play an important role in maintaining bone mineral density in elderly women.

Assessing the Impact of a Hilly Environment on Depressive Symptoms among Community-Dwelling Older Adults in Japan: A Cross-Sectional Study.

Although some neighborhood environmental factors have been found to affect depressive symptoms, few studies have focused on the impact of living in a hilly environment, i.e., land slope, on depressive symptoms among rural older adults. This cross-sectional study aimed to investigate whether a land slope is associated with depressive symptoms among older adults living in rural areas. Data were collected from 935 participants, aged 65 years and older, who lived in Shimane prefecture, Japan. Depressive symptoms were assessed using the Zung Self-Rating Depression Scale (SDS) and defined on the basis of an SDS score ≥ 40. Land slopes within a 400 m network buffer were assessed using geographic information systems. Odds ratios (ORs) with 95% confidence intervals (CIs) of depressive symptoms were estimated using logistic regression. A total of 215 (23.0%) participants reported depressive symptoms. The land slope was positively associated with depressive symptoms (OR = 1.04; 95% CI = 1.01-1.08) after adjusting for all confounders. In a rural setting, living in a hillier environment was associated with depressive symptoms among community-dwelling older adults in Japan.

Inconvenience of Living Place Affects Individual HbA1c Level in a Rural Area in Japan: Shimane CoHRE Study.

BACKGROUND: It has been shown that the socio-geographical environment of residential areas, such as altitude, affects the health status and health-maintenance behavior of residents. Here, we examined a hypothesis that altitude of residence would influence glycemic control in a general elderly population living in a rural area. METHODS: A thousand and sixteen participants living in a mountainous region in Japan were recruited at health examinations. Hemoglobin A1c (HbA1c) was measured in serum as a parameter of glycemic control. The altitude of residence, distance to grocery stores and to medical facilities were estimated using a geographic information system. RESULTS: Linear regression analysis confirmed a significant effect of the altitude on log HbA1c even after adjustment of other demographic and biochemical factors. When the distance to grocery stores or medical facilities were used instead of the altitude in a linear regression analysis, distance to secondary medical facilities alone showed a significant effect on HbA1c. CONCLUSIONS: We found a positive correlation between HbA1c level and residential altitude in a rural area of Japan. The altitude seemed to be a parameter substituting the inconvenicence of residential areas. Socio-geographical factors of living place, such as inconvenience, may influence glycemic control of the residents.

Serological screening for celiac disease in adults in Japan: Shimane CoHRE study.

BACKGROUND AND AIM: Celiac disease (CD) is a chronic autoimmune enteropathy triggered by ingested gluten in genetically predisposed individuals. Although common in Europe and the United States, cases of CD are rarely encountered in East Asia, including Japan, and its prevalence remains to be fully evaluated in a large-scale study. We previously investigated the presence of CD in adults in Japan, which revealed a low prevalence of 1 (0.05%) of 2008 nonclinical subjects, while 1 (2.1%) of 47 symptomatic patients was diagnosed based on serology and duodenal histopathology results. To confirm those results, we conducted an additional retrospective serological screening study of adults in Japan. METHODS: Serum samples were collected from 2055 adults who underwent a health examination in four local areas of Shimane prefecture in Japan from July 2008 to August 2013. As a screening test for CD, the antitissue transglutaminase IgA antibody (TTG) titer was determined in all subjects, and a value greater than 10 U/mL was considered to be evidence of CD. RESULTS: Of the 2055 subjects, 4 (0.19%) showed a high concentration of TTG. Although two of the four who were seropositive had died at the time of this retrospective study, none reported prominent digestive symptoms such as diarrhea or weight loss in a follow-up survey. CONCLUSIONS: Among a general population in Japan, a positive rate of serological tests for CD was noted in 0.19%, indicating quite a low presence, consistent with our previous results.

Hilly environment and physical activity among community-dwelling older adults in Japan: a cross-sectional study.

OBJECTIVES: We investigated whether a moderate-to-vigorous physical activity (MVPA) level and walking time were associated with a hilly environment in rural Japanese older adults. DESIGN: Cross-sectional study. SETTING: Unnan city, Ohnan and Okinoshima towns in Shimane, Japan. PARTICIPANTS: Data were collected from 1115 adults from the Shimane CoHRE study, who were aged 60 years and older and living in rural Japan in 2012. MEASURES: We measured the total time spent on MVPA and walking using a Japanese short version of the International Physical Activity Questionnaire. The land slope in 400 or 800 m network buffers was assessed using the geographic information system. A multivariable Poisson regression model examined the prevalence ratios (PR) and 95% CIs of walking time or MVPA levels meeting the WHO guideline (>150 min/week) in the land slope categories (low, middle and high), adjusted for confounders. RESULTS: Engaging in the recommended level of MVPA was significantly associated with middle land slope (PR=1.07; p=0.03) and high land slope (PR=1.06; p=0.07) compared with low land slope in the 400 m network buffer, as well as with middle land slope (PR=1.02; p=0.48) and high land slope (PR=1.04; p=0.25) compared with the low land slope in the 800 m network buffer. Walking time was significantly associated with middle land slope (PR=1.13; p=0.04) and high land slope (PR=1.17; p=0.01) compared with low land slope in the 400 m network buffer, and with middle land slope (PR=1.09; p=0.16) and high land slope (PR=1.17; p<0.01) compared with low land slope in the 800 m network buffer. The sensitivity analysis found only a positive association between walking time and land slope in the 400 and 800 m network buffers. CONCLUSIONS: This study showed that a hilly environment was positively associated with walking time among older adults living in rural Japan.

Prevalence of lifestyle-related chronic diseases among agricultural and non-agricultural workers in ruralareas of Japan: the Shimane CoHRE study.

Objective: Engaging in agriculture greatly affects workers' lifestyles, particularly related to physical activity. This study aimed to clarify the prevalence of lifestyle-related chronic diseases among workers engaging and not engaging in agriculture in rural areas of Japan. Methods: A total of 4,666 consecutive participants aged ≥40 years (1,929 men and 2,737 women) were recruited during health examinations conducted from 2006 to 2014. For analysis, the participants were divided by sex and age into those engaging in agriculture and those not engaging in agriculture. Results: Engaging in agriculture may be contributing with a low prevalence of dyslipidemia, a constitutive factor of metabolic syndrome, in both sexes between the ages of 40 and 64 years. In the elderly aged ≥65 years, engaging in agriculture may influence the low prevalence of hypertension in men. Hypertension, a strong risk factor for stroke and cardiovascular disease, is very frequent among the Japanese elderly and, therefore, engaging in agriculture may have a significant impact on its prevention and control. Conclusion: In rural areas of Japan, engaging in agriculture may contribute to the control of lipid metabolism in middle-aged individuals and blood pressure in the elderly.

J-curve association between alcohol intake and varicose veins in Japan: The Shimane CoHRE Study.

The effect of alcohol intake on varicose veins (VV) has not been determined by its consumption level. The aim of this study was to investigate the association between alcohol intake and VV in an elderly general population. Using a cross-sectional approach, the Shimane CoHRE Study data, comprising a total of 1060 participants, were analyzed. By multivariate regression analysis adjusted with basic characteristics, past work history, lifestyle-related factors and medical history, compared with non-drinkers, mild drinkers (<20.0 g/day) showed a significantly lower adjusted odds ratio (aOR) of VV (aOR = 0.64, P = 0.036). In a similar way, regular drinkers (1-5 days/week) showed a significantly lower aOR of VV when compared with occasional drinkers (aOR = 0.57, P = 0.032). VV and alcohol intake showed J-curve relationships. In a stratified analysis by alcohol consumption levels, the association of smoking and VV were also observed in moderate to heavy drinkers and habitual drinkers. These findings can provide better understanding of pathophysiological mechanism and be used for evidence-based patient education.

Relationship between Individual Social Capital and Cognitive Function among Older Adults by Gender: A Cross-Sectional Study.

As it is not easy to modify lifestyle, it is important to examine the effect of social capital (SC), which does not require behavior modifications, on dementia prevention. This study aimed to clarify gender differences in the relationship between cognitive function and individual SC among people living in a rural area in Japan. We used the Shimane Center for Community-based Healthcare Research and Education (CoHRE) study data from 2011 to conduct a cross-sectional analysis. The analysis included 491 participants, aged 40 years or older, who had undergone medical examinations in two rural towns in Japan. Both cognitive SC and structural SC were measured. Multivariate logistic regression analysis was conducted to estimate the odds ratios (OR) and 95% confidence interval (CI) for cognitive function levels as binary outcomes. We found a significant association between cognitive function and individual cognitive SC in men (OR: 3.11, 95% CI: 1.43-6.78), and found that cognitive function was associated with structural SC in women (OR: 1.89, 95% CI: 1.08-3.31). This study showed that the relationship between cognitive function and individual SC differed by gender. These results suggest that it is important to approach dementia prevention differently in men and women.

Height loss but not body composition is related to low back pain in community-dwelling elderlies: Shimane CoHRE study.

BACKGROUND: Low back pain (LBP) is a common complaint in the elderly Japanese population. Although previous studies showed that height loss was associated with LBP, it remains unclear whether LBP is associated with body composition. The objective of the present study was to investigate whether body composition and physical characteristics, including height loss, were associated with LBP. METHODS: The present study is retrospectively registered, and the participants were 2212 community-dwelling Japanese people aged over 60 years who participated in the Shimane CoHRE study in 2016. We investigated the presence of LBP, body composition parameters (muscle, fat, body weight, and bone mass), physical characteristics (body height and height loss), chronic diseases, history of fall, smoking, and drinking habits. We examined the relationships of body composition parameters and physical characteristics with point prevalence of LBP using multivariate logistic regression. RESULTS: The point prevalence of LBP was 43.2% in women and 39.5% in men. Logistic regression models showed that body height and body composition were not significantly associated with LBP; however, height loss was associated significantly with LBP in women and men (OR: 1.14, 95% CI: 1.08-1.20 and OR: 1.13, 95% CI: 1.06-1.21, respectively). Hypertension (OR: 1.32, 9 5% CI: 1.04-1.69) and chronic heart disease (OR: 1.57, 95% CI: 1.01-2.43) in women and history of fall (OR: 1.70, 95% CI: 1.13-2.56) and cerebrovascular disease (OR: 1.88, 95% CI: 1.05-3.34) in men were significantly associated with LBP. However, body composition was not associated with LBP in either gender. CONCLUSIONS: The present study demonstrated that height loss, but not body composition, was related to LBP in community-dwelling elderly people. To elucidate the cause of LBP, it is important to consider the relationship with height loss.

Hilly neighborhoods are associated with increased risk of weight gain among older adults in rural Japan: a 3-years follow-up study.

BACKGROUND: Neighborhood environments have been regularly associated with the weight status. Although the evidence is mostly limited to adults residing in western urban settings, the weight status of older adults living in rural areas is also assumed to be significantly affected by their neighborhood environments. This study aimed to identify environmental attributes specific to rural areas that could affect the risk of longitudinal weight gain among older adults (≥ 65 years) in Japan. METHODS: We examined five environmental attributes, i.e., land slope, public transportation accessibility, residential density, intersection density, and the availability of parks and recreational centers, measured by the geographic information system. Our analysis was based on 714 subjects participated in Shimane Community-based Healthcare Research and Education study in 2012 and 2015. Multinomial logistic regression model was conducted to examine the association between each neighborhood environmental attribute and weight change status (gain, loss and unchanged). RESULTS: We observed a significant increase in the risk of weight gain as the steepness of the neighborhood land slope increased. There was no significant association between other environmental attributes and risk of weight gain as well as weight loss among older adults. CONCLUSION: Living in hilly neighborhoods was associated with increased risk of weight gain among rural Japanese older adults. Future research should consider region-specific environmental attributes when investigating their effect on older adults' weight status.

Additive Effect of Physical Activity and Sedentary Time on Depressive Symptoms in Rural Japanese Adults: A Cross-Sectional Study.

BACKGROUND: Previous studies have reported an additive effect of moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) on depressive symptoms. However, no studies have been conducted in rural community settings. This cross-sectional study investigated whether the additive effect of MVPA and ST was associated with depressive symptoms in rural Japanese adults. METHODS: We identified 2,814 participants from health examinations conducted in Shimane, rural Japan, in 2012 and analyzed data from 1,958 participants. We assessed depressive symptoms using the Zung Self-Rating Depression Scale and measured the total time spent on MVPA and ST using a Japanese short version of the International Physical Activity Questionnaire. Poisson regression analysis examined the prevalence ratios (PR) of depressive symptoms in nine category combinations of MVPA level (no, insufficient, or sufficient MVPA) and ST level (high, moderate, or low ST). RESULTS: A total of 117 (6.0%) participants had depressive symptoms. Compared with the reference category (no MVPA/high ST), multivariate analysis showed that the likelihood of depressive symptoms was significantly lower in the sufficient MVPA/low ST category (PR 0.23; 95% confidence intervals [CI], 0.08-0.66), insufficient MVPA/low ST category (PR 0.37; 95% CI, 0.16-0.86), and insufficient MVPA/moderate ST category (PR 0.39; 95% CI, 0.17-0.90). CONCLUSION: Analysis of the additive effect of MVPA and ST showed that the combinational category of sufficient MVPA and low ST had the lowest prevalence of depressive symptoms in rural Japanese adults. Moderate ST and low ST showed significantly lower likelihoods of depressive symptoms, regardless of insufficient MVPA.

Association of High-Density Lipoprotein Subclasses with Carotid Intima-Media Thickness: Shimane CoHRE Study.

AIMS: Recent studies suggested that subclasses of high-density lipoprotein (HDL) may be a better biomarker to predict the risk of atherosclerotic disorders. We aimed to examine the association of HDL2- and HDL3-cholesterol (HDL2-C and HDL3-C) with carotid intima-media thickness (IMT) using a new method to quantify the HDL-C subclasses. METHODS: Participants were 657 Japanese subjects (434 women) who received a health examination (mean age: 73 years). Serum samples were analyzed by the homogenous assay for HDL-C and HDL3-C. HDL2-C was calculated indirectly by subtracting HDL3-C from HDL-C. HDL3-C measured by this assay was well correlated with that measured by ultracentrifugation (r=0.898, p＜0.001). The maximum IMT (max-IMT) and plaque score (PS) were evaluated by ultrasonography following the standard protocol. RESULTS: HDL3-C was associated with age both in men (r=－0.322, p＜0.0001) and women (r=－0.315, p＜0.0001). In a simple regression analysis, max-IMT showed an inverse association with HDL3-C, whereas no significant association was observed with HDL2-C. A multiple linear regression analysis indicated, however, that the association between HDL3-C and max-IMT was not significant in both aged and younger populations when age was included in the analysis. Further, not only HDL2-C but also HDL3-C was not a significant predictor of 'atherosclerotic arteries' defined as the max-IMT ≥1.5 mm. Similar results were observed in the analysis on PS. CONCLUSIONS: Neither HDL3-C nor HDL2-C was significantly associated with carotid atherosclerosis in the Japanese population in this study.

Is the Effect of Body Mass Index on Hypertension Modified by the Elevation? A Cross-Sectional Study of Rural Areas in Japan.

Obesity is an established independent risk factor for developing hypertension. A recent study showed that the effect of obesity on hypertension varies by the elevation of the residence area. Thus, we hypothesized that the interaction effect of body mass index (BMI) and elevation has a significant association with hypertension. The first aim of this cross-sectional study was to examine whether BMI was associated with hypertension, after adjustment for covariates. The second aim was to examine whether the interaction term between BMI and elevation was associated with hypertension, after adjustment for covariates. Data were collected from a cross-sectional study conducted in a rural area of Japan in 2016. After excluding participants with missing data (n = 2), data from 729 participants were analyzed. We found that BMI was significantly associated with hypertension. In addition, the interaction term between BMI and elevation had a significant association with hypertension. The findings of the present study support the recent evidence that high BMI is an independent risk factor for hypertension, but its effect varies by elevation. Thus, context-specific interventions could be an effective approach to prevent hypertension in this area.

Is Accessibility to Dental Care Facilities in Rural Areas Associated with Number of Teeth in Elderly Residents?

Given that public transportation networks are less developed in rural than in urban areas, a lack of accessibility to dental care facilities could be a barrier to routine dental checkups. Thus, we hypothesized that the distance to the dental care facilities is a risk factor for tooth loss. The aim of this study was to test whether there is an association between the distance to dental care facilities, estimated by geographic information systems, and number of teeth, assessed by an oral examination, among elderly residents of a rural area in Japan. Data were collected in 2016 from a cross-sectional study conducted in Shimane prefecture, Japan. After excluding participants with missing data (n = 21), we analyzed data from 710 participants. Of them, 40.6% were male and the mean (standard deviation) age was 67.4 (7.4) years. Further, 68.0% (n = 483) had at least 20 teeth. We found that the distance to dental care facilities was significantly associated with the number of teeth (less than 20) (odds ratio = 1.07, 95% confidence interval = 1.01-1.12) after adjustment for potential confounders. This result suggested that individuals without easy access to dental care facilities may be important targets for dental care.