Published papers

A 10-year follow-up cohort study of 4,535 National Health Insurance beneficiaries aged 40 to 69 years in Shiga was performed as part of a research project conducted by the Health Promotion Research Committee of the Shiga National Health Insurance Organizations in 2002. The relationship between cardiovascular risk factors and medical expenditures during the 10-year study period has been examined in this cohort. For example, there was a positively graded correlation between blood pressure and individual total medical expenditures per month. The odds ratio for cumulative hospitalization and hazard ratio for all-cause mortality in severe hypertensives were also higher than those in normotensives. However, from the viewpoint of the entire population, the excess medical expenditures attributable to hypertension within the total medical expenditures were higher for mild-to-moderate hypertensives than for severe hypertensives. On the other hand, although individual medical expenditures per month were 1.7-fold higher for participants with 2 or 3 risk factors and obesity, which was broadly equivalent to metabolic syndrome, than for those without these factors, the excess medical expenditures determined by risk clustering within the total medical expenditures were higher in normal-weight people than in obese people because of the higher prevalence of normal weight. These findings suggest that high-risk individuals are a good target of a high-risk approach, such as intensive health guidance, from the viewpoint of medical expenditures. However, another approach for the majority with a low-to-moderate cardiovascular risk should be considered, because they account for a greater proportion of the excess medical expenditures. Another way to solve this problem may be a population approach with an effective method of providing information to citizens.

Objective: Recently, several major organizations have proposed a unified definition for the metabolic syndrome (MetS), which should be evaluated in multiethnic groups. The effect of Mets on the incidence of cardiovascular disease needs to be assessed after adjusting for serum low density lipoprotein cholesterol (LDLC), a major risk factor for atherosclerotic diseases. This is especially needed to be evaluated in Asian populations with low incidence of coronary artery disease (CAD). Methods: We conducted a 13-year prospective study of 4939 Japanese living in an urban area. The MetS was defined using a unified classification that included cut-off points for waist circumference in Asians. The multivariable adjusted hazard ratios (HRs) of MetS for CAD and stroke were calculated using a Cox proportional model adjusted for other potential confounding factors with LDLC. Results and conclusion: During the follow-up period, there were 155 cases of CAD and 204 of stroke including 118 cerebral infarctions. In participants under 65 years old, the multivariable HRs of MetS for CAD were 1.21 (95% C.I., 0.64-2.28) in men and 4.44 (95% C.I., 1.73-11.4) in women; the HRs for ischemic stroke were 3.24 (95% C.I., 1.55-6.77) in men and 3.99 (95% C.I., 1.34-11.8) in women. In participants aged 65 years old and over, MetS only showed a significant association with CAD in men (HR 1.89, 95% C.I., 1.11-3.21). Serum LDLC was associated with increased risk of CAD in men irrespective of age group; however, it was not associated with CAD in women. There was no association between serum LDLC and ischemic stroke in any group stratified by sex and the age of 65. These results indicate that the new uniform MetS definition is useful for detecting high risk individuals, especially for middle-aged population. However, continuous screening for hypercholesterolemia is necessary to prevent CAD, especially in men, even in Asian countries such as Japan. © 2011 Elsevier Ireland Ltd.

Background and aims Several studies have reported a significant inverse association of light to moderate alcohol consumption with coronary heart disease (CHD). However, studies assessing the relationship between alcohol consumption and atherosclerosis have reported inconsistent results. The current study was conducted to determine the relationship between alcohol consumption and aortic calcification. Methods We addressed the research question using data from the population-based ERA-JUMP Study, comprising of 1006 healthy men aged 40–49 years, without clinical cardiovascular diseases, from four race/ethnicities: 301 Whites, 103 African American, 292 Japanese American, and 310 Japanese in Japan. Aortic calcification was assessed by electron-beam computed tomography and quantified using the Agatston method. Alcohol consumption was categorized into four groups: 0 (non-drinkers), ≤1 (light drinkers), >1 to ≤3 (moderate drinkers) and >3 drinks per day (heavy drinkers) (1 drink = 12.5 g of ethanol). Tobit conditional regression and ordinal logistic regression were used to investigate the association of alcohol consumption with aortic calcification after adjusting for cardiovascular risk factors and potential confounders. Results The study participants consisted of 25.6% nondrinkers, 35.3% light drinkers, 23.5% moderate drinkers, and 15.6% heavy drinkers. Heavy drinkers [Tobit ratio (95% CI) = 2.34 (1.10, 4.97); odds ratio (95% CI) = 1.67 (1.11, 2.52)] had significantly higher expected aortic calcification score compared to nondrinkers, after adjusting for socio-demographic and confounding variables. There was no significant interaction between alcohol consumption and race/ethnicity on aortic calcification. Conclusions Our findings suggest that heavy alcohol consumption may be an independent risk factor for atherosclerosis.

Background: Diabetes mellitus is a strong risk factor for cardiovascular disease. However, the age-specific association of diabetes with cardiovascular risk, especially in the elderly, remains unclear in non-Western populations. Methods: A pooled analysis was conducted using 8 cohort studies (mean follow-up period, 10.3 years) in Japan, combining the data from 38,854 individual participants without history of cardiovascular disease. In all, 1867 of the participants had diabetes, defined based on the 1998 World Health Organization criteria. The association between diabetes and the risk of death from cardiovascular disease, coronary heart disease (CHD), and stroke was estimated using a stratified Cox model, accounting for variability of baseline hazard functions among cohorts. Results: During the follow-up, 1376 subjects died of cardiovascular disease (including 268 of coronary heart disease and 621 of stroke). Diabetes was associated with an increased risk of cardiovascular death after multivariable adjustment (hazard ratio [HR] 1.62; 95% confidence interval [CI], 1.35-1.94). Similarly, diabetes was a risk factor for CHD (HR 2.13; 95% CI, 1.47-3.09) and stroke (HR 1.40; 95% CI, 1.05-1.85). In the age-stratified analysis of the risk of cardiovascular death, the relative effects of diabetes were consistent across age groups (p for heterogeneity = 0.18), whereas the excess absolute risks of diabetes were greater in participants in their 70s and 80s than in younger subjects. Conclusions: The management of diabetes is important to reduce the risk of death from cardiovascular disease, not only in midlife but also in late life, in the Japanese population.

Low levels of serum high-density lipoprotein cholesterol (HDL-C) have been shown to be associated with increased risk of coronary heart disease (CHD). However, because this is usually observed in the context of other lipid abnormalities, it is not known whether isolated low serum HDL-C levels are an independent risk factor for CHD. We performed a large pooled analysis in Japan using data from nine cohorts with 41,206 participants aged 40–89 years who were free of cardiovascular disease at baseline. We divided participants into three groups: isolated low HDL-C, non-isolated low HDL-C, and normal HDL-C. Cohort-stratified Cox proportional hazards models were used to estimate multivariate-adjusted hazard ratios (HRs) for death due to CHD, ischemic stroke, and intracranial cerebral hemorrhage; during a 12.9-year follow-up, we observed 355, 286, and 138 deaths, respectively, in these groups. Non-isolated low HDL-C was significantly associated with increased risk of CHD compared with normal HDL-C (HR 1.37, 95 % confidence interval (CI) 1.04–1.80); however, isolated low HDL-C was not. Although isolated low HDL-C was significantly associated with decreased risk of CHD (HR 0.51, 95 % CI 0.29–0.89) in women, it was significantly associated with increased risk of intracranial cerebral hemorrhage in all participants (HR 1.62, 95 % CI 1.04–2.53) and in men (HR 2.00, 95 % CI 1.04–3.83). In conclusion, isolated low HDL-C levels are not associated with increased risk of CHD in Japan. CHD risk may, therefore, be more strongly affected by serum total cholesterol levels in this population.

Aims: This study investigated the relationship between alcohol drinking habits and the onset of high medical expenditure in a Japanese male population. Methods: The cohort comprised 94,307 male beneficiaries 40-69 years of age of the Japanese medical insurance system, who had daily alcohol drinking habits. The likelihood of incurring high medical expenditure, defined as the ≥90th percentile of the medical expenditure distribution in the study population 1 year after baseline, as well as the likelihood of undergoing hospitalization that year were compared among the participants grouped according to their alcohol consumption amount (<2, 2-3.9, 4-5.9, ≥6 drinks/day). Results: Participants who ranked in the top 10% medical expenditure group within the 1 year after baseline each incurred at least 2152 euros/year. The top 10% medical expenditure group accounted for 61.1% of the total medical expenditure in the study population. The odds ratios (95% confidence intervals) for ranking in the top 10% group during the 1-year period, compared with the <2 drinks (23 g of alcohol)/day group, were 1.08 (1.02-1.15) for 2-3.9 drinks/day, 1.11 (1.05-1.19) for 4-5.9 drinks/day, and 1.31 (1.18-1.45) for ≥6 drinks/day after adjustment for age, body mass index, and smoking and exercise habits. The adjusted odds ratios for undergoing hospitalization were 1.11 (1.04-1.19), 1.14 (1.06-1.24) and 1.39 (1.24-1.56), respectively. Conclusion: The likelihood of incurring high medical expenditure and undergoing hospitalization increased with daily alcohol consumption amount.

Background: Low-density lipoprotein particle (LDL-P) has recently been found to be a stronger predictor of cardiovascular disease (CVD) than LDL-cholesterol (LDL-C). Objectives: Whether LDL-P is associated with subclinical atherosclerosis, independent of LDL-C, as well as other lipid measures has not been fully examined. We aimed to analyze LDL-P associations with measures of subclinical atherosclerosis. Methods: We examined 870 Japanese men randomly selected from Kusatsu City, Shiga, Japan, aged 40-79 years from 2006-2008, free of clinical CVD and not using lipid-lowering medication. Cross-sectional associations of lipid measures with carotid intima-media thickness (cIMT) and coronary artery calcification (CAC; >0 Agatston score) were examined. Results: LDL-P was significantly positively associated with cIMT and maintained this association after adjustments for LDL-C and other lipid measures. Although these lipid measures were positively associated with cIMT, model adjustment for LDL-P removed any significant relationships. Higher LDL-P was associated with a significantly higher odds ratio of CAC and further adjustment for LDL-C did not affect this relationship. In contrast, the LDL-C association with CAC was no longer significant after adjustment for LDL-P. Other lipid measures attenuated associations of LDL-P with CAC. Likewise, associations of these measures with CAC were attenuated when model adjustments for LDL-P were made. Conclusions: In a community-based sample of Japanese men, free of clinical CVD, LDL-P was a robust marker for subclinical atherosclerosis, independent of LDL-C and other lipid measures. Associations of LDL-C and other lipid measures with either cIMT or CAC were generally not independent of LDL-P.

© 2018 National Lipid Association Background: The effect of very high or extremely high levels of high-density lipoprotein cholesterol (HDL-C) on cardiovascular disease (CVD) is not well described. Although a few recent studies have reported the adverse effects of extremely high levels of HDL-C on CVD events, these did not show a statistically significant association between extremely high levels of HDL-C and cause-specific CVD mortality. In addition, Asian populations have not been studied. Objective: We examine the impact of extremely high levels of HDL-C on cause-specific CVD mortality using pooled data of Japanese cohort studies. Methods: We performed a large-scale pooled analysis of 9 Japanese cohorts including 43,407 participants aged 40–89 years, dividing the participants into 5 groups by HDL-C levels, including extremely high levels of HDL-C ≥2.33 mmol/L (≥90 mg/dL). We estimated the adjusted hazard ratio of each HDL-C category for all-cause death and cause-specific deaths compared with HDL-C 1.04–1.55 mmol/L (40–59 mg/dL) using a cohort-stratified Cox proportional hazards model. Results: During a 12.1-year follow-up, 4995 all-cause deaths and 1280 deaths due to overall CVD were identified. Extremely high levels of HDL-C were significantly associated with increased risk of atherosclerotic CVD mortality (hazard ratio = 2.37, 95% confidence interval: 1.37–4.09 for total) and increased risk for coronary heart disease and ischemic stroke. In addition, the risk for extremely high HDL-C was more evident among current drinkers. Conclusion: We showed extremely high levels of HDL-C had an adverse effect on atherosclerotic CVD mortality in a pooled analysis of Japanese cohorts.

© 2018, The Japanese Society of Hypertension. While the association between 24-h urinary sodium and potassium excretion with blood pressure is well established, the relationships of these ions to spot urine measurements are unclear. Our purpose is to assess the association between blood pressure and the estimated 24-h sodium and potassium excretion from repeated single-spot urine samples. Spot urine and blood pressure were collected annually during a 5-year period from 4360 Japanese workers with ages ranging from 19 to 55 years. Estimates of 24-h sodium and potassium excretion were based on Tanaka’s formula. Overall, a single standard deviation increase in the estimated sodium excretion (36.5 mmol/day) was associated with a 1.3 mmHg higher systolic blood pressure and a 0.8 mmHg higher diastolic blood pressure (P < 0.001). A single standard deviation increase in estimated potassium excretion (8.9 mmol/day) was associated with a 1.1 mmHg lower systolic blood pressure and a 0.7 mmHg lower diastolic blood pressure (P < 0.001). As a combined measure of the excretion of both electrolytes, the estimated 24-h sodium-to-potassium ratio was positively associated with both blood pressures (P < 0.001). Associations of blood pressure with sodium and the sodium-to-potassium ratio increased with age and were stronger in men compared to women. Associations with potassium and the sodium-to-potassium ratio were stronger in individuals who were overweight. The findings provide evidence for an association between blood pressure and the estimated 24-h sodium and potassium excretion from repeated single-spot urine samples. As convenient measures of dietary intake for each electrolyte, repeated spot urine samples may be useful for assessing hypertension risk, especially in men, older individuals, and overweight individuals.

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. The present study sought to clarify if being conscious of water intake (CWI) is associated with sufficient non-alcohol drink (NAD) intake. We used data of healthy participants without diabetes, aged 40–74 years, in the Kobe Orthopedic and Biomedical Epidemiologic (KOBE) study. The association between being CWI and NAD intake was evaluated by multivariate linear regression analyses after adjusting for age, sex, surveyed months (seasons), alcohol drinking, health-awareness life habits, socioeconomic factors, serum osmolarity, estimated daily salt intake, and reasons for NAD intake. Among 988 (698 women and 290 men) participants eligible for the present analyses, 644 participants (65.2%) were CWI and 344 participants (34.8%) were not CWI (non-CWI). The most popular reason for being CWI was to avoid heat stroke in summer and to prevent ischemic cerebral stroke in winter. The CWI group took more NAD, especially decaffeinated beverages, than the non-CWI group (1846.7 ± 675.1 mL/day vs. 1478.0 ± 636.3 ml/day, p < 0.001). There was a significant association between being CWI and NAD intake in multivariate linear regression analyses ever after adjusting for the relevant variables (β = 318.1, p < 0.001). These findings demonstrated CWI, regardless of the reasons and the seasons, was associated with high NAD intake in Japanese healthy population.

Cardio-embolic ischemic stroke caused by atrial fibrillation is more severe compared with other types of stroke, such as lacunar infarction and atherothrombotic infarction in patients without atrial fibrillation. Therefore, it is important to prevent cardio-embolic ischemic stroke by detecting atrial fibrillation early in at-risk patients and administering appropriate anticoagulation therapy. This prospective observational study aimed to evaluate the effectiveness of opportunistic atrial fibrillation screening at 12 primary clinics in Japan. The study included a 12-month pre-campaign period and a 12-month campaign period. During the campaign period, an awareness campaign was conducted to encourage physicians to be mindful of screening patients aged 65 years for atrial fibrillation by checking their pulses and performing subsequent electrocardiography when an irregular pulse was detected. The primary outcome was the proportion of patients with newly diagnosed atrial fibrillation. A sub-analysis focusing on first-time outpatients was performed. There were 9921 and 10,282 patients with no history of atrial fibrillation in the pre-campaign and campaign periods, respectively. In the whole population, the proportion of patients with newly diagnosed atrial fibrillation was 0.9% throughout the pre-campaign and campaign periods. In the sub-analysis limited to first-time outpatients, the detection proportion increased from 1.6% to 1.9% during the campaign period. In terms of age stratification, a large increase in detection was observed, especially among patients aged 65–74 years (detection increased from 0.9% to 1.5%) and 85 years (detection increased from 2.9% to 3.3%) during the campaign period. Our findings suggest the feasibility of opportunistic atrial fibrillation screening in routine primary care practice in Japan. Of note, our findings suggest that opportunistic atrial fibrillation screening targeting first-time outpatients may be of clinical value.

Background: Recently, identification of independent risk factors for ischemic stroke in Japanese non-valvular atrial fibrillation (NVAF) patients was made by analyzing the 5 major Japanese registries: J-RHYTHM Registry, Fushimi AF Registry, Shinken Database, Keio interhospital Cardiovascular Studies, and the Hokuriku-Plus AF Registry. Methods and Results: The predictive value of the risk scheme in Japanese NVAF patients was assessed. Of 16,918 patients, 12,289 NVAF patients were analyzed (mean follow up, 649±181 days). Hazard ratios (HRs) of each significant, independent risk factor were determined by using adjusted Cox-hazard proportional analysis. Scoring system for ischemic stroke was created by transforming HR logarithmically and was estimated by c-statistic. During the 21,820 person-years follow up, 241 ischemic stroke events occurred. Significant risk factors were: being elderly (aged 75-84 years [E], HR=1.74), extreme elderly (≥85 years [EE], HR=2.41), having hypertension (H, HR=1.60), previous stroke (S, HR=2.75), type of AF (persistent/permanent) (T, HR=1.59), and low body mass index <18.5 kg/m2(L, HR=1.55) after adjusting for oral anticoagulant treatment. The score was assigned as follows: 1 point to H, E, L, and T, and 2 points to EE and S (HELT-E2S2score). The C-statistic, using this score, was 0.681 (95% confidence interval [CI]=0.647-0.714), which was significantly higher than those using CHADS2(0.647; 95% CI=0.614-0.681, P=0.027 for comparison) and CHA2DS2-VASc scores (0.641; 95% CI=0.608-0.673, P=0.008).

Objectives To date, the association between accumulated unhealthy behaviours and insomnia in individuals stratified according to the presence or absence of major cardiovascular risk factors is unclear. This study aimed to examine the effect of accumulated unhealthy behaviours on insomnia in Japanese dwellers. Design Cross-sectional study. Setting Baseline data between April 2012 and March 2015. Participants Our study used cross-sectional data among Japanese aged 35-74 years in a rural community (N=9565), the attendees of annual municipal or work site health check-up programmes. Main outcome measures Insomnia was assessed by Athens Insomnia Scale, which was set at 6 points and greater; other scales were given. Participants were categorised into three groups by their number of unhealthy behaviours (no exercise habit, smoking, alcohol drinking, skipping breakfast and obesity): 0-1, 2-3, 4 or more. The association between accumulated unhealthy behaviours and insomnia was estimated by logistic regression analysis. Further analysis was done after stratification of cardiovascular risk factors assessed by anthropometrics and clinical biochemistry measurements. Results The overall prevalence of insomnia was 13.3% for men and 19.3% for women. Men with unhealthy behaviour factors were more likely to have insomnia after adjusting for potential confounders, compared with the least unhealthy group (trend p=0.013). Women with four or more unhealthy behaviour factors were more likely to have insomnia, compared with the lowest groups (OR 1.175, 95% CI 1.077 to 1.282). Insomnia has an association with the unhealthy behaviours among men without cardiovascular risk factors (lowest groups: OR 1.133, 95% CI 1.037 to 1.238, trend p=0.026). Women without hypertension were more likely to have suspected insomnia, compared with the lowest group (OR 1.215, 95% CI 1.101 to 1.341). Conclusion The results showed accumulated unhealthy behaviours were associated with increased risk of insomnia in Japanese dwellers. For healthy population without cardiovascular risk factors, unhealthy behaviours should be considered as background conditions for insomnia.

Aims: The potential effect of alcohol consumption on coronary heart disease (CHD) remains unclear. We used the variant rs671 in the aldehyde dehydrogenase 2 gene (ALDH2) as an instrument to investigate the causal role of alcohol intake in subclinical and clinical CHD. Methods: We conducted two Mendelian randomization studies: a cross-sectional study of coronary artery calcification (CAC) on computed tomography of 1029 healthy men (mean age, 63.8 years) and a case-control study of 421 men with CHD [acute coronary syndrome (ACS) or stable angina pectoris] who underwent coronary revascularization and 842 age-matched male controls. Results: In the CAC study, medians (25%tiles, 75%tiles) of alcohol consumption by ALDH2-rs671 ∗2 homozygotes [n = 86 (8.4%)], ∗1∗2 heterozygotes [n = 397 (38.5%)], and ∗1 homozygotes [n = 546 (53.1%)] were 0.0 (0.0, 0.0), 28.0 (0.0, 129.0), and 224.0 (84.0, 350.0) g/week, respectively. In age-adjusted Poisson regression with robust error variance, compared with ∗2 homozygotes, relative risks for prevalent CAC score >0, ≥100, and ≥300 in ∗1 homozygotes were 1.29 (95% confidence interval, 1.06-1.57), 1.76 (1.05-2.96), and 1.81 (0.80-4.09), respectively. In age-adjusted ordinal logistic regression for CAC distributions, we observed higher odds among ∗1 homozygotes [odds ratio, 2.19 (1.39-3.46)] and even among ∗1∗2 heterozygotes [1.77 (1.11-2.82)] compared with ∗2 homozygotes. In the case-control study, conditional logistic regression revealed lower prevalence of ∗1 homozygotes among men with CHD [odds ratio, 0.54 (0.35-0.82)], especially ACS [0.46 (0.27-0.77)], than controls. Conclusion: Our findings indicate a positive association of alcohol consumption with CAC burden but an inverse association with clinical CHD, especially ACS.

Background and purpose: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a new target for reducing low-density lipoprotein cholesterol and incident cardiovascular disease, including stroke. However, the clinical relevance of circulating PCSK9 levels has been poorly elucidated in the general population, particularly in association with subclinical cerebrovascular disease including cerebral small vessel disease (CSVD) and intracranial artery stenosis (ICAS). Methods: In community-dwelling Japanese men (n = 526) aged 46–82 years without a history of cardiovascular disease, the associations of serum PCSK9 levels with the prevalence of CSVD and ICAS were assessed using magnetic resonance imaging. CSVD included lacunar infarction, deep and subcortical white matter hyperintensity, periventricular hyperintensity and cerebral microbleeds. Results: The median (interquartile range) age at baseline and serum PCSK9 levels were 69 (63–74) years and 240 (205–291) ng/ml, respectively. After adjusting for traditional cardiovascular risk factors including low-density lipoprotein cholesterol, multivariable Poisson regression with robust error variance revealed a significant association between PCSK9 levels (per 1 SD) and ICAS (relative risks 1.18, 95% confidence interval 1.02–1.37). Multivariable ordinal logistic regression for ICAS, with stenosis graded as mild (<50%) or moderate–severe (≥50%), revealed a similar association (common odds ratio 1.31, 95% confidence interval 1.04–1.64). However, no significant association was observed between serum PCSK9 levels and CSVD. Conclusions: Higher circulating PCSK9 levels were independently associated with an ICAS prevalence but not with CSVD prevalence. The quantification of circulating PCSK9 levels may help to identify individuals at high risk for cerebrovascular disease in the general population.