Miwako Takeda

Effect of Environmental and Lifestyle Factors on Hypertension: Shimane COHRE Study

Background In recent years there has been increasing evidence of an association between residential remoteness and hypertension (HTN); however, no study has examined the effects of residential remoteness-lifestyle associations on HTN. The objective of this study was to evaluate the effects of residential remoteness, as measured by road network distance and elevation, and lifestyle associations, including access to daily products as a measure of car use, on HTN in a rural region in Japan. Method This is a cross-sectional population based study. We analyzed data from the Shimane COHRE study conducted from 2006 to 2009 in the rural mountainous regions of Japan. After excluding missing data, we conducted a logistic regression analysis of the data for 1,348 individuals and examined the effects of residential remoteness and lifestyle associations, including road network distance, elevation and access to daily products as a measure of car use, on the prevalence of HTN. Principal Findings In participants without access to car use, the odds ratios for self-reported HTN (i.e. taking antihypertensive medication) were significantly increased in those living in moderate (odds ratio (OR): 2.21, 95% confidence interval (CI): 1.19–4.08) and far (OR: 2.55, 95% CI: 1.00–6.51) road distances, whereas there were no significant associations in participants with access to car use. There were no significant associations between elevation and HTN for participants either with or without access to car transportation. Conclusions Our findings show that specific residential remoteness-hypertension associations vary according to access to daily products as a measure of car use in a rural mountainous area of Japan. These results advance the understanding and importance of considering residential environment, “where people live,” in establishing health policy.

Is Location Associated With High Risk of Hypertension? Shimane COHRE Study

BACKGROUND There is growing evidence that residential environment is associated with hypertension. Recently, interest has also turned toward examining the possible influence of remoteness on hypertension. The aim of this study is to explore the effect of remoteness, the shortest path between the subject location and the population center, on hypertension prevalence in a rural region in Japan. METHODS We analyzed data from the Shimane COHRE Study conducted from 2006 to 2009 in rural mountainous regions of Japan. After excluding the missing data, we conducted a logistic regression analysis of the data for 1,348 individuals. Geographic information systems (GIS) were used in the network analysis. Network analysis determined the distance between subjects location and population center on road networks, and the distance was divided into tertiles: 0-26,685.8 m = close distance, 26,685.9 m-38,350.6 m = moderate distance, 38,350.7 m-68,070.1 m = far distance. RESULTS According to self-reported hypertension, the odds ratios for hypertension (taking antihypertensive medication or under treatment for hypertension without medication) were 1.44 (95% confidence interval (CI): 1.04-1.99) and 1.78 (95% CI: 1.29-2.46) in moderate and far distances, respectively, after adjustment for potential confounders. The odds ratios no longer remained significant after considering the measurement of blood pressure (BP) to define hypertension (taking antihypertensive medication or under treatment for hypertension without medication or BP ≥ 140/90 mm Hg for systolic BP (SBP)/diastolic BP (DBP)). CONCLUSIONS Our findings show that residential remoteness might be associated with a higher risk of hypertension in a rural region in Japan.

Relationship between Blood Myostatin Levels and Kidney Function:Shimane CoHRE Study

Objectives Myostatin (MSTN), a member of TGF-β superfamily, is produced in the skeletal muscle to inhibit myocyte differentiation. MSTN expression is increased in the skeletal muscle in patients with chronic kidney disease (CKD), which may play a role in the pathogenesis of sarcopenia or in the protein energy wasting (PEW). This observation implies that the plasma MSTN level may be correlated with kidney function. Thus, we conducted a cross-sectional study to evaluate the association between the plasma MSTN concentration and the estimated glomerular filtration rate (eGFR). Subjects and Methods Subjects were 781 participants of a health examination performed in a rural area in Japan. Among them, 124 subjects were selected by stratified random sampling according to eGFR. Creatinine clearance (ClCr) by the Cockcroft-Gault equation was used as a measure of kidney function. Plasma concentration of MSTN was determined by ELISA. Results The plasma MSTN level was not different between men (3.42±1.61 ng/mL) and women (3.27±1.43 ng/mL). In a simple regression analysis, the MSTN level was significantly correlated with eGFR (r = -0.25, p<0.01) and ClCr (r = -0.20, p<0.05) but not with age and BMI. In a multiple linear regression analysis, the MSTN level showed a negative correlation with eGFR (standardized β = -0.31, p<0.01) and ClCr (standardized β = -0.35, p<0.01) under the adjustment with age, sex, BMI and LDL-C. Weak correlation was observed between the MSTN level and BMI / the serum LDL-C level. When the subjects were stratified into 4 groups according to eGFR, MSTN was significantly greater in the groups with the lowest and the 2nd lowest eGFR (3.55±1.79 and 3.76±1.75 ng/mL, respectively) than the level in the group with the highest eGFR (2.77±0.85 ng/mL). Conclusion Plasma MSTN level was elevated in an early stage of CKD, which could be involved in the progression of sarcopenia.

Altitudes of residential areas affect salt intake in a rural area in Japan: a Shimane CoHRE Study.

There is increasing evidence of an association between residential environments and hypertension. As shown in our previous study, the inconvenience of the locations of residential areas may be one of the factors influencing the blood pressures of inhabitants. Salt intake is one of the likely mediators between inconvenience and hypertension. Therefore, in this study, we evaluated the association between the altitudes of residential areas and salt intake in a rural Japanese region because altitude may be one of the proxies for inconvenience. In this cross-sectional study, 1016 participants living in a mountainous region in Japan were recruited during health examinations. The altitude of each participant’s residence was estimated using a geographic information system. Subjects were divided into quartile groups according to the altitudes of their residences. To evaluate salt intake, we employed the 24-h salt intake estimation of Kawano et al. (e24-h salt intake) and the urinary sodium-to-potassium ratio (uNa/K). Linear regression analyses indicated that altitude was an independent factor influencing both e24-h salt intake and uNa/K after adjustments for age, sex, body mass index, physical activity, alcohol consumption, triglycerides and county of residence. The same result was observed when the subjects who did not take antihypertensive medications were analyzed (N=633). The present study indicated that altitude of residence had a significant positive influence on salt intake in a rural area of Japan.

Standing posture at work and overweight exacerbate varicose veins: Shimane CoHRE Study

Varicose veins (VV) in legs are commonly observed in the general global population. However, the prevalence of and risk factors for VV in Japan are not clear. This study aimed at clarifying the risk factors for VV in traditional rural areas of Shimane prefecture. Subjects (113 men and 205 women aged ≥45 years) were recruited from health examinations in those areas in 2012. VV were defined as a reflux of blood in the great and/or small saphenous vein and incompetent perforating veins detected by ultrasonography. Risk factors for VV were analyzed using logistic regression models that included various parameters. We also investigated the possible interaction between standing at work and overweight and calculated the synergistic index. VV were found in 20.1% of the subjects (12.4% of men and 24.4% of women). The previously known risk factors of prolonged upright standing posture during work, higher body mass index (BMI), female sex, and age were also significant factors for VV. There was a significant combined effect of overweight (BMI ≥25) and prolonged upright standing posture at work [adjusted odds ratio = 3.42; 95% confidence interval (CI), 1.07–10.89], although the synergistic effect was not significant [synergistic index = 1.3; 95% CI, 0.2–8.7]. The prevalence of VV in the traditional rural area of Shimane prefecture was comparable to that reported previously in European countries. Our results confirm that exposure to both prolonged standing at work and overweight exacerbate VV development. This finding is useful to develop strategies for VV prevention.

Effect of salt intake on blood pressure in patients receiving antihypertensive therapy: Shimane CoHRE Study

BACKGROUND Salt intake is recognized as an important risk factor for hypertension in the general population. On the other hand, the availability of various classes of antihypertensive drugs means that it is generally not considered crucial to control the salt intake of hypertensive patients. In this study, we evaluated whether blood pressure (BP) was correlated with 24-hour salt intake in patients receiving antihypertensive therapy. METHODS A total of 1496 consecutive participants undergoing health screening examinations were recruited. Subjects were divided into two groups according to their antihypertensive medications checked on prescriptions: 1005 subjects without antihypertensive therapy (untreated subjects) and 491 subjects with antihypertensive therapy (treated subjects). The 24-hour urinary sodium excretion (24h-uNa), a surrogate marker for daily salt intake, was estimated with the formula proposed by Tanaka et al. in 2002. RESULTS Univariate analysis indicated that 24h-uNa was positively correlated with the systolic BP of both untreated and treated subjects. This was confirmed by multiple linear regression analysis after adjustment for confounding factors (untreated subjects: partial regression coefficient β=1.45 ± 0.26, p<0.001; treated subjects: β=0.75 ± 0.27, p=0.01). Salt intake was also correlated with the pulse pressure in both treated subjects (β=0.55 ± 0.24, p=0.02) and untreated subjects (β=0.93 ± 0.19, p<0.001). CONCLUSION These results suggest the importance of reducing salt intake in hypertensive patients on pharmacotherapy, as well as in the general population. Further studies of hypertensive patients employing 24-h urine collection are warranted to confirm the present findings.

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 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.

Association Between Geographic Elevation, Bone Status, and Exercise Habits: The Shimane CoHRE Study

In recent years, there has been growing interest in the association between the residential environment and health. The association between residential environment (i.e., geographic elevation) and bone status is unknown. Furthermore, these associations could differ by exercise habits due to the chronically greater daily activity caused by steep slopes in mountainous areas. The aim of this study was to test whether the association between bone status of elderly people measured using quantitative ultrasound (QUS) and elevation varied according to the exercise habits in a mountainous area population. Data were collected from a cross-sectional study conducted during 2012–2013. QUS value was expressed as a proportion of the young adult mean (%YAM), with higher scores donating better bone status. After excluding subjects with missing data, we analyzed the data for 321 men and 500 women. Our results indicate that %YAM was not associated with elevation among men, or among women with exercise habits. However, elevation was associated with %YAM among women without exercise habits. Our results highlight the importance of considering residential environment and exercise habits when establishing promotion strategies to maintain bone status of the elderly people who live in rural mountainous areas.

Accessible transportation, geographic elevation, and masticatory ability among elderly residents of a rural area

Given that public transportation networks are often worse in rural areas than in urban areas, rural residents who do not drive can find it difficult to access health-promoting goods, services, and resources related to masticatory ability. Moreover, geographical location, assessed by elevation, could modify this association. The aim of this study was to test whether the association between access to transportation and masticatory ability varied by elevation. Data were collected from a cross-sectional study conducted in Mizuho and Iwami counties, Japan. Objective masticatory ability was evaluated using a test gummy jelly and elevation was estimated by the geographic information systems according to the participant’s address. After excluding subjects with missing data, 672 subjects (Mizuho = 401 and Iwami = 271) were analyzed. After adjustment for potential confounders, being a driver was not significantly associated with masticatory ability among elderly people living at low elevation (≤313 m) in Mizuho county. However, after the same adjustment, being a driver remained significantly associated with increased masticatory ability among elderly at high elevations. Similar findings were observed in Iwami county. Accessible transportation was significantly associated with increased mastication ability in elderly people living at high elevations, but not in those living at low elevations.