Published papers

Importance: Despite the development of risk stratification schemes that have been widely used to determine the risk for thromboembolism in patients with nonvalvular atrial fibrillation (NVAF), risk stratification schemes in Asian patients with NVAF remain undetermined. Objective: To determine risk factors for ischemic stroke in Japanese patients with NVAF. Design, Setting, and Participants: This cohort study analyzed individual patient data from 5 AF registries in Japan: J-RHYTHM (Japanese Rhythm Management Trial for Atrial Fibrillation) Registry, Fushimi AF Registry, Shinken Database, Keio Interhospital Cardiovascular Studies (Keio Study), and Hokuriku-Plus AF Registry. Patients with atrial fibrillation were registered from 158 institutions in the J-RHYTHM Registry, 80 in the Fushimi AF Registry, a single hospital in Shinken Database, 11 in the Keio Study, and 19 in the Hokuriku-Plus AF Registry. Patients with valvular AF or lacking data were excluded. Data were collected and integrated in March 2016, and those from the Keio Study were updated in April 2018. Data were analyzed from April 2018 to February 2020. Main Outcomes and Measures: Significant risk factors for ischemic stroke were determined by adjusted Cox proportional hazards analysis. Results: In total, 12 289 patients with NVAF (3758 [31%] female; mean [SD] age 70.2 [11] years) were analyzed with a mean (SD) follow-up period of 649 (181) days (1.8 [0.5] years). During 21 820 person-years of follow-up, 241 cases of ischemic stroke were reported. Risk factors associated with ischemic stroke after adjustment for oral anticoagulant use at enrollment were age (75-84 years: hazard ratio [HR], 1.74; 95% CI, 1.32-2.30; P < .001; and ≥85 years: HR, 2.41; 1.63-3.56; P < .001), hypertension (HR, 1.60; 95% CI, 1.15-2.23; P = .006), previous stroke (HR, 2.75; 95% CI, 2.09-3.62; P < .001), persistent or permanent AF (HR, 1.59; 95% CI, 1.21-2.10; P = .001), and body mass index less than 18.5 (HR, 1.55; 95% CI, 1.05-2.29; P = .03). Neither diabetes nor heart failure were identified as risk factors for ischemic stroke. Conclusions and Relevance: Previous stroke, advanced age, hypertension, persistent or permanent AF, and low body mass index were independent risk factors associated with ischemic stroke in Japanese patients with NVAF.

Lippincott Williams &Wilkins.OBJECTIVE: This study investigated the effect of hypertension on hospitalization risk and medical expenditure according to treatment status in a Japanese population. METHODS: A total of 314 622 beneficiaries of the medical insurance system in Japan, aged 40-69 years, without a history of cardiovascular, cerebrovascular, or end-stage renal disease were classified into seven blood pressure categories. These categories were used to compare the risk of undergoing hospitalization in the 1 year after the baseline survey and to examine the percentage of inpatient medical expenditure attributable to overall hypertension relative to total medical expenditure in the study population. RESULTS: During the follow-up period, 6.6% of men and 5.1% of women were hospitalized. In men and women aged 40-54 years, cases of hypertension, especially grade 3 untreated hypertension, led to more frequent hospitalization, compared with optimal blood pressure. Individuals who were hospitalized, especially long-term, incurred considerably higher medical expenditure compared with those who were not hospitalized, regardless of their hypertension status. In women aged 55-69 years, there was little variation in hospitalization risk across blood pressure categories. The inpatient medical expenditure attributable to overall hypertension represented 7.2 and 6.9% of the total medical expenditure for men aged 40-54 and 55-69 years, whereas it represented 2.8 and 3.8% for women, respectively. CONCLUSION: Although cases of hypertension were an economic burden especially in men, grade 3 untreated hypertension was more likely to incur extremely high medical expenditure as a result of hospitalization, compared with other cases. © 2013 Wolters Kluwer Health

Aim: The relationship between psychosocial characteristics and smoking cessation behavior was examined among Japanese male ever-smokers with type 2 diabetes mellitus. Methods: The psychosocial characteristics and smoking cessation behavior of 441 male ever-smokers with type 2 diabetes mellitus were investigated. Personality was assessed using an egogram (five ego states: the Critical Parent, Nurturing Parent, Adult, Free Child, and Adapted Child) and each patient was classified into a high score or low score group based on the median. The current smokers were divided into 2 categories according to their readiness to quit smoking. Results: In multivariate analyses, the ever-smokers with a high Adult score had a lower risk of current smoking (OR=0.67, 95%CI=0.41-0.93), the ever-smokers with a high Free Child score were over 3 times more likely to currently smoke (OR=3.12, 95%CI=1.97-4.97), and the ever-smokers who had a low educational background had a higher risk of current smoking (OR=3.02, 95% CI=1.73-5.28). In addition, the current smokers with a high Adult score had a lower risk of being in the immotive and precontemplation stage (OR=0.55, 95%CI=0.24-0.96). The current smokers who had a low educational background had a higher risk of being in the immotive and precontemplation stage (OR=2.13, 95%CI=1.08-5.42). Conclusion: There is a need to develop a smoking cessation program for patients with high "Free Child" scores and a "low education level".

Background and Purpose:Body mass index is most commonly used as the obesity index. Recently, waist circumference (WC) has been shown to be associated with the risk of cardiovascular disease (CVD). However, no studies have observed an association between WC and CVD in Japan. We examined the relationships of WC and body mass index with CVD in a Japanese urban population. Methods-We studied 5474 Japanese individuals (aged 30 to 79 years without CVD at baseline) who completed a baseline survey and received follow-up through December 2005. WC was measured at the umbilical level of participants in the standing position to the nearest 1 cm. The Cox proportional hazard ratios for CVD according to the quartiles of WC were calculated after adjustment for age, smoking, and drinking status. Results-During a mean follow-up of 11.7 years, 207 strokes and 133 myocardial infarctions were documented. In women, compared with the lowest quartile (WC <70 cm), the hazard ratio (95% CIs) after adjusting for age, smoking, and drinking in the highest quartile (WC ≥84 cm) were 1.85 (1.03 to 3.31) for CVD and 2.64 (1.16 to 6.03) for stroke. However, no such relationships of WC with CVD or stroke risk were observed in men. After further adjustment of hypertension, diabetes, and hypercholesterolemia, all of the mentioned relationships were not statistically significant. No associations of body mass index with CVD or strokes were observed. Conclusions:s:WC may be a better predictor for CVD or stroke in Japanese women. © 2010 American Heart Association, Inc.

Objective: The impact of elevated triglycerides (TG) and non-high density lipoprotein cholesterol (non-HDLC) on the incidence of stroke and myocardial infarction (MI) has not been well evaluated in Asian populations such as in Japan, which have a lower incidence of myocardial infarction, but a higher risk of stroke than Western populations. Methods: The authors conducted an 11.7-year prospective study ending in 2005 of 5098 Japanese aged 30-79 living in an urban population, initially free of stroke or MI. The relationship between serum lipids and the risk for stroke and MI was determined by dividing the participants into four groups stratified by the combination of serum levels of TG and non-HDLC. The cut-off value was 1.7 mmol/L for TG and 4.9 mmol/L for non-HDLC. Results and conclusion: The total person-years were 59,774 (27,461 for men and 32,313 for women). During the follow-up period, there were 113 cases of MI and 180 of stoke (with 116 cerebral infarctions). Compared with the low TG/low non-HDLC group, the hazard ratio (95% confidence interval) for MI in the high TG/high non-HDLC group was 2.55 (1.53-4.24) after adjustment for other cardiovascular risk factors. The hazard ratio for cerebral infarction in the high TG alone group was 1.63 (1.03-2.56); however, the risk of cerebral infarction was not significantly increased in the other groups. High serum levels of TG and non-HDLC are both important targets for the prevention of cardiovascular disease in Japan. © 2009 Elsevier Ireland Ltd. All rights reserved.

Background: Although underweight young women are targets for interventions to prevent low bone mineral density (BMD), the relationship between change in body mass index (BMI) from youth to older age and BMD has not been widely investigated in community dwellers. Methods: In 749 healthy Japanese women aged 40-74 years, BMD was measured by quantitative ultrasound and anthropometric measurements, and BMI was calculated from body weight and height. The BMI of participants at age 20 years was estimated by self-reported body weight and their present height. They were classified into four groups according to the presence of underweight (BMI <18.5 kg/m2) at 20 and/or at present. Logistic regression models were used to estimate multivariate-adjusted odds ratios (ORs) of the presence of underweight at 20 and/or at present for osteopenia (BMD T score <-1 standard deviations) compared with participants with BMI ≥18.5 kg/m2 both at 20 and at present. Results: The participants who were underweight both at 20 and at present had a higher OR for osteopenia compared with those with BMI ≥18.5 kg/m2 at 20 and at present (OR 3.94; 95% confidence interval [CI], 1.97-7.89). Those underweight only at present also had significantly increased OR of developing osteopenia (OR 2.95; 95% CI, 1.67-5.24). The OR of those underweight only at 20 was 0.87 (95% CI, 0.51-1.48). Conclusions: Current underweight was associated with increased risk for osteopenia among Japanese women, especially in those who were underweight both at 20 and at present. To prevent low BMD in the future, maintaining appropriate body weight might be effective for young underweight women.

The aim of this study was to clarify the relationship between long-term changes in body mass index (BMI) during childhood and adolescent blood-pressure levels in a general Japanese population. We used health report data from 900 Japanese children between 1983 and 2007. After adjusting for baseline BMI and other confounding factors multivariate linear regression analyses were performed to examine the relationship between changes in BMI (ΔBMI) over a 6-year period (6-12 years) and blood pressure once children reached ages 14 or 15. Sub-group analyses were also performed to ascertain the relationship between ΔBMI and blood pressure at 9th grade for children who had been in the bottom BMI tertile at 1st grade. Endpoint blood-pressure levels in boys (systolic and diastolic) and girls (systolic) from the group whose BMIs increased the most were significantly higher than those from the group whose BMIs increased the least (P<0.05, analysis of variance). After adjustment for baseline BMI and school-entrance year, the former group showed higher blood pressure at the endpoint than the latter (P<0.05, multiple regression analysis). Further adjustment for baseline blood pressure also showed similar results in a combined-sex analysis (n=592). Higher ΔBMI was associated with higher SBP 9 even in children whose BMI was in the lowest tertile at baseline after adjustment for sex and school-entrance year (P=0.02, multiple regression analysis). Steeper BMI increases during primary school lead to adolescent increases in blood pressure even if baseline BMI is low. Growth during childhood should be carefully managed. © 2014 The Japanese Society of Hypertension All rights reserved.