Hideki Sugihara

Brachial–ankle pulse wave velocity predicts all-cause mortality in the general population: findings from the Takashima study, Japan

Brachial–ankle pulse wave velocity (baPWV) is a relatively new non-invasive measure of arterial stiffness obtained using an automated system. We assessed the relationship between baPWV and 6.5-year overall mortality from the Takashima cohort study. The baPWV was measured in 2642 participants at baseline. When participants were divided into tertiles, all-cause mortality increased significantly as baPWV increased (P<0.001). Participants in the highest baPWV tertile showed an increased risk of all-cause mortality evidenced by a multivariable adjusted hazard ratio of 6.8 (95% confidence interval: 1.4–32.8) as compared with the lowest tertile. The present study demonstrated that increased baPWV is an independent predictor of all-cause mortality in the Japanese population.

Higher stroke incidence in the spring season regardless of conventional risk factors: Takashima Stroke Registry, Japan, 1988-2001.

Background and Purpose— Seasonal variation in stroke incidence was examined using 14-year stroke registration data in a Japanese population. We also examined if this variation was modified by conventional stroke risk factors hypertension, diabetes mellitus, drinking, and smoking. Methods— Data were obtained from the Takashima Stroke Registry, which covers a stable population of ≈55 000 in Takashima County in central Japan. There were 1665 (men, 893; women, 772) registered first-ever stroke cases during 1988 to 2001. The average age of stroke onset for men and women patients was 69.4 and 74.2 years, respectively. Incidence rates (per 100 000 person-years) and 95% CI were calculated by gender, age, and stroke subtype for winter, spring, summer, and autumn. After stratifying patients by their risk factor history, the OR (with 95% CI) of having a stroke in autumn, winter, and spring were calculated, with summer serving as a reference. Results— Among the seasons, stroke incidence per 100 000 person-years was highest in the spring (231.3; 95% CI, 211.1 to 251.5). Spring incidence was highest in both men (240.8; 95% CI, 211.5 to 270.2) and women (222.1; 95% CI, 194.4 to 249.9), and in subjects younger than 65 years (72.6; 95% CI, 60.0 to 85.3) and 65 years or older (875.9; 95% CI, 787.5 to 964.3). Among stroke subtypes, spring incidence was highest for cerebral infarction (154.7; 95% CI, 138.2 to 171.2) and cerebral hemorrhage (53.7; 95% CI, 44.0 to 63.4). The spring excess in stroke incidence was observed regardless of the presence or absence of the risk factor histories. Conclusions— Stroke incidence appears to be highest in the spring among a Japanese population regardless of conventional risk factor history. Factors that explain this excess need further investigation.

Ischemic Stroke Subtypes in a Japanese Population Takashima Stroke Registry, 1988–2004

Background and Purpose— Population-based information on the epidemiology of ischemic stroke (IS) subtypes is scant. In this study, we characterized IS subtypes in terms of incidence, time trend, and risk factor profiles in a community-based population. Methods— We obtained data from the Takashima Stroke Registry on approximately 55 000 residents of Takashima County in central Japan and calculated age-adjusted stroke incidence rates for different IS subtypes. We determined the incidence time trend by calculating the average annual change across years and also compared risk factors between subtypes. Results— There were 1389 first-ever ischemic strokes registered during 1988 to 2004. Lacunar infarction was the most frequent etiology (54.1%) followed by cardioembolic infarction (22.9%). Age-adjusted incidence rates for different IS subtypes were lacunar, 77.1; cardioembolic, 31.5; and nonlacunar, 29.7/105 person-years. The average annual change was not significant for the IS subtypes except for nonlacunar infarction, which showed a decreasing trend. Risk factor analysis showed that patients with lacunar infarctions were younger and less likely to have a history of transient ischemic attack or a drinking habit than patients with nonlacunar infarctions. Conclusion— Lacunar infarct was the most common IS subtype in our population. We found no significant change in the incidence of subtypes during the study, except a decrease in nonlacunar infarction.

Trend of Stroke Incidence in a Japanese Population: Takashima Stroke Registry, 1990-2001:

Background In Japan, stroke mortality and incidence started to decline during the 1960s. The recent unfavourably diverging trends in risk factors make it uncertain whether the decline will continue. Few comprehensive stroke registries of long research duration exist in Japan to illustrate the trends in stroke incidence. Objective We examined 12-year stroke registration data to evaluate the current trend in a Japanese population. Methods Data were obtained from the Takashima Stroke Registry, covering approximately 55000 residents of Takashima County in central Japan. We calculated the age-adjusted stroke incidence rates (/100 000 person-years) and 95% confidence intervals for 1990–1992, 1993–1995, 1996–1998, and 1999–2001. We applied the direct method to adjust for the age distribution among the four periods. The incidence time trend was determined by calculating the average annual change across the study years using negative binomial regression analysis. Results There were 1453 (men: 771 and women: 682) registered first-ever stroke cases during 1990–2001. The diagnosis was established by neuro-imaging in 93·6% of the cases. The average age was 69·4 years in men and 74·2 years in women. The age-adjusted incidence rates of stroke across the four observation periods were 143·1 (confidence interval: 127·4-158·8) in 1990–1992, 147·4 (confidence interval: 131·9–162·8) in 1993–1995, 120·4 (confidence interval: 106·7–134·0) in 1996–1998, and 122·9 (confidence interval: 109·6–136·2) in 1999–2001. The stroke incidence across the study years showed an insignificant time trend, with an average annual change of −0·33% (confidence interval: −2·44 to 1·78) per year. Similar trends were observed for both men and women and stroke subtypes. Conclusions The previously reported declining trend in stroke incidence may have levelled off or slowed down considerably in the Japanese population.

Seasonal Pattern of Incidence and Case Fatality of Acute Myocardial Infarction in a Japanese Population (from the Takashima AMI Registry, 1988 to 2003)

We examined the seasonal variations in the incidence and case fatality of acute myocardial infarction (AMI) in a geographically defined population using 16-year AMI registration data. It remains unclear whether the incident events of AMI display any seasonal variation. Documentation of such a pattern may foster investigation for understanding the potential mechanisms responsible for these effects and may provide novel avenues for prevention of AMI. Data were obtained from the Takashima AMI Registry, which covers an entire community of approximately 55,000 in central Japan. There were 335 definite cases of AMI during 1988 to 2003 (217 men, 118 women). Of these, there were 96 fatal cases (53 men, 43 women) within 28 days of onset. Incidence rates (per 100,000 person-years) and case fatality rates with 95% confidence intervals (CI) were calculated across seasons. Poisson regression analysis was used to calculate the incidence rate, and case fatality ratios adjusted for age and gender. The AMI incidence rate was higher in winter (44.9, 95% CI 35.9 to 53.9) and spring (44.1, 95% CI 35.3 to 52.9) than the other seasons. After adjustment for age and gender, AMI risk was 1.4 (95% CI 1.03 to 1.9) times higher in winter and was 1.4 (95% CI 1.01 to 1.9) times higher in spring than summer. The 28-day AMI case fatality rate was also higher in winter (34.4%, 95% CI 24.9 to 43.9) and spring (32.3%, 95% CI 22.9 to 41.7). Age- and gender-adjusted fatality risk was 2.4 (95% CI 1.2 to 4.9) times higher in winter and 2.3 (95% CI 1.1 to 4.6) times higher in spring than summer. In conclusion, higher AMI incidence and case fatality rates were observed in winter and spring in a Japanese population.

The relationship of brachial-ankle pulse wave velocity to future cardiovascular disease events in the general Japanese population: the Takashima Study.

Brachial-ankle pulse wave velocity (baPWV) is a non-invasive measure of arterial stiffness obtained using an automated system. Although baPWVs have been widely used as a non-invasive marker for evaluation of arterial stiffness, evidence for the prognostic value of baPWV in the general population is scarce. In this study, we assessed the association between baPWV and future cardiovascular disease (CVD) incidence in a Japanese population. From 2002 to 2009, baPWV was measured in a total of 4164 men and women without a history of CVD, and they were followed up until the end of 2009 with a median follow-up period of 6.5 years. Hazard ratios (HRs) for CVD incidence according to baPWV levels were calculated using a Cox proportional hazards model adjusted for potential confounding factors, including seated or supine blood pressure (BP). During the follow-up period, we observed 40 incident cases of CVD. In multivariable-adjusted model, baPWV as a continuous variable was not significantly associated with future CVD risk after adjustment for supine BP. However, compared with lower baPWV category (<18 m s−1), higher baPWV (⩾18.0 m s−1) was significantly associated with an increased CVD risk (HR: 2.70, 95% confidence interval: 1.18–6.19). Higher baPWV (⩾18.0 m s−1) would be an independent predictor of future CVD event in the general Japanese population.

Stroke case fatality shows seasonal variation regardless of risk factor status in a Japanese population: 15-year results from the Takashima Stroke Registry.

Background: Seasonal variation in fatality caused by stroke was examined using 15 years of data from a stroke registry of a Japanese population. Methods: Data were obtained from the Takashima Stroke Registry, which covers approximately 55,000 residents in central Japan. There were 1,650 registered cases of first-ever stroke between 1988 and 2002. 7- and 28-day fatality rates and 95% confidence intervals were calculated for winter, spring, summer and autumn. After adjusting for gender, age at onset and risk factors, the hazard ratios for fatal strokes in winter, spring and autumn were calculated, with summer serving as the reference. Results: For cerebral infarction, the highest 7- and 28-day fatality rates occurred during spring and winter, where they were more than double the rate during summer. The severest strokes were also more likely to occur during winter and spring. A high spring and winter hazard ratio for 28-day mortality was present in both lacunar and nonlacunar subtypes, in both genders and in subjects <65 and ≥65 years of age. No apparent seasonal pattern was observed for cerebral hemorrhage or subarachnoid hemorrhage. The spring and winter excess fatality persisted even after adjusting for age, gender and risk factors. Conclusion: Patients who suffer an ischemic stroke during winter or spring have a poorer prognosis. Further investigation is needed to determine the factors that explain this excess risk.

Increase of Stroke Incidence after Weekend Regardless of Traditional Risk Factors: Takashima Stroke Registry, Japan; 1988–2003

Background and Purpose: The study purpose was to identify patterns of variation in stroke incidence among days of the week and examine if it is modified by conventional stroke risk factors: hypertension, diabetes, drinking and smoking. Methods: Data were obtained from the Takashima Stroke Registry, which covers a stable population of roughly 55,000 residents of Takashima County in central Japan. A total of 1,773 stroke cases (men: 943 and women: 830) occurred between 1988 and 2003. We divided the days into 3 groups: ‘weekend’, ‘after weekend’ and ‘rest of the week’, and calculated stroke incidence rates and incidence rate ratios. To identify the effect of conventional risk factors on the variation, proportion of differences between observed and expected stroke incidences were considered. Results: The stroke incidence for the after weekend group (250.1 per 100,000 person years, 95% CI: 222.0–278.3) was higher than for the other day groups among men. The after weekend increase was observed mainly among older men aged 65 years or more. Among the stroke subtypes, the incidence for cerebral infarction was highest in the after weekend group (857.2, 95% CI: 730.6–983.8) and was 1.37 times (95% CI: 1.12–1.68) higher than in the rest of the week group. Tendency of after weekend increase was observed regardless of the presence or absence of risk factor history. Conclusions: Week day variation for stroke was observed predominantly among older men regardless of presence and absence of risk factor history. Information about the weekly trend regarding episode of increased stroke incidence can be used as a surrogate predictor for stroke onset and would be helpful in designing more effective insights for preventive strategies.

Morning surge in circadian periodicity of ischaemic stroke is independent of conventional risk factor status: findings from the Takashima Stroke Registry 1990-2003.

Background:  We examined the circadian periodicity of ischaemic stroke (IS) onset and its relationship with conventional risk factors using 14‐year stroke registration data.

Short-term exposure to air pollution and incidence of stroke and acute myocardial infarction in a Japanese population.

Background: Exposure to high levels of air pollution can increase the risk of cardiovascular events. However, there is no clear information in Japan on the effect of pollution on the incidence of stroke and acute myocardial infarction (AMI). Therefore, we investigated the effects of air pollution on the incidence of stroke and AMI in a setting where pollutant levels are rather low. Methods: Data were obtained from the Takashima Stroke and AMI Registry, which covers a population of approximately 55,000 in Takashima County in central Japan. We applied a time-stratified, bidirectional, case-crossover design to estimate the effects of air pollutants, which included suspended particulate matter (SPM), sulfur dioxide (SO2), nitrogen dioxide (NO2) and photochemical oxidants (Ox). We used the distributed lag model to estimate the effect of pollutant exposure 0-3 days before the day of event onset and controlled for meteorological covariates in all of the models. Results: There were 2,038 first-ever strokes (1,083 men, 955 women) and 429 first-ever AMI cases (281 men, 148 women) during 1988-2004. The mean pollutant levels were as follows: SPM 26.9 µg/m3; SO2 3.9 ppb; NO2 16.0 ppb, and Ox 28.4 ppb. In single-pollutant and two-pollutant models, SO2 was associated with the risk of cerebral hemorrhage. Other stroke subtypes and AMI were not associated with air pollutant levels. Conclusions: We observed an association between SO2 and hemorrhagic stroke; however, we found inconclusive evidence for a short-term effect of air pollution on the incidence of other stroke types and AMI.