Prognostic value of ST-T abnormalities and left high R waves with cardiovascular mortality in Japanese (24-year follow-up of NIPPON DATA80)

Little is known about the prognostic value of ST-segment depression and/or T wave (ST-T abnormalities) with or without left high R waves on electrocardiogram recorded at rest for death from cardiovascular disease (CVD) in Asian populations. Japanese participants without a history of CVD and free of major electrocardiographic (ECG) abnormalities were followed for 24 years. Subjects were divided into 4 groups based on baseline ECG findings: isolated left high R waves, isolated ST-T abnormalities, ST-T abnormalities with left high R waves, and normal electrocardiogram. Cox proportional hazard model was used to estimate risk of CVD mortality in groups with ECG abnormalities compared to the normal group. Of 8,572 participants (44.4% men, mean age 49.5 years; 55.6% women, mean age 49.4 years), 1,142 had isolated left high R waves, 292 had isolated ST-T abnormalities, and 128 had ST-T abnormalities with left high R waves at baseline. Multivariable-adjusted hazard ratios of ST-T abnormalities with left high R waves for CVD mortality were 1.95 (95% confidence interval 1.25 to 3.04) in men and 2.68 (95% confidence interval 1.81 to 3.97) in women. Isolated ST-T abnormalities increased the risk for CVD death by 1.66 times (95% confidence interval 1.01 to 2.71) in men and 1.62 times (95% confidence interval 1.18 to 2.24) in women. Association of ECG abnormalities with CVD mortality was independent of age, body mass index, systolic blood pressure, serum cholesterol, blood glucose, smoking and drinking, and antihypertensive medication. In conclusion, ST-T abnormalities with or without left high R waves on electrocardiogram recorded at rest constitute an independent predictor of CVD mortality in Japanese men and women.

Residual lifetime risk of cardiovascular diseases in Japan

Risk assessment of cardiovascular diseases (CVD) is shifting from the relative risk to an absolute risk approach. The residual lifetime risk (LTR), which provides an absolute risk assessment, is an epidemiologic measure that expresses the probability of someone of a given age and sex developing a disease condition during their remaining lifespan. The LTR estimation is important because it could be more easily comprehended by clinicians and patients. The LTR for CVD was not estimated for the Japanese population until recently, when the LTR of stroke and acute myocardial infarction (AMI) was reported. The reported LTR of stroke and AMI for middle-aged adults is substantial. The observed probabilities illustrated that approximately 1 in 5 men and women of middle age will suffer from a stroke in their remaining lifetime. On the other hand, approximately 1 in 6 men and 1 in 9 women of middle age will suffer from AMI in their remaining lifetime. Aaginst the backdrop of the aging population and worsening risk factor scenario, these estimates re-emphasize that CVD is a public health burden that requires preventive interventions. These estimates provide a means to communicate the absolute risk of CVD to the lay population, policy makers, as well as health service providers in predicting the disease burden of CVD. This easily comprehended knowledge can be used as an important index to assist in public health education and planning.

Profile of participants and genotype distributions of 108 polymorphisms in a cross-sectional study of associations of genotypes with lifestyle and clinical factors: a project in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study

Background

Most diseases are thought to arise from interactions between environmental factors and the host genotype. To detect gene–environment interactions in the development of lifestyle-related diseases, and especially cancer, the Japan Multi-institutional Collaborative Cohort (J-MICC) Study was launched in 2005.

Methods

We initiated a cross-sectional study to examine associations of genotypes with lifestyle and clinical factors, as assessed by questionnaires and medical examinations. The 4519 subjects were selected from among participants in the J-MICC Study in 10 areas throughout Japan. In total, 108 polymorphisms were chosen and genotyped using the Invader assay.

Results

The study group comprised 2124 men and 2395 women with a mean age of 55.8 ± 8.9 years (range, 35–69 years) at baseline. Among the 108 polymorphisms examined, 4 were not polymorphic in our study population. Among the remaining 104 polymorphisms, most variations were common (minor allele frequency ≥0.05 for 96 polymorphisms). The allele frequencies in this population were comparable with those in the HapMap-JPT data set for 45 Japanese from Tokyo. Only 5 of 88 polymorphisms showed allele-frequency differences greater than 0.1. Of the 108 polymorphisms, 32 showed a highly significant difference in minor allele frequency among the study areas (P < 0.001).

Conclusions

This comprehensive data collection on lifestyle and clinical factors will be useful for elucidating gene–environment interactions. In addition, it is likely to be an informative reference tool, as free access to genotype data for a large Japanese population is not readily available.

Time lag to hospitalisation and the associated determinants in patients with acute myocardial infarction: the Takashima AMI Registry, Japan

BACKGROUND

Prompt initiation of treatment is the cornerstone in the management of patients with acute myocardial infarction (AMI). The time lags for AMI hospitalisations were examined to identify the factors influencing the interval.

METHODS

Time lag information was available for 273 men and 148 women from the Takashima AMI Registry during 1988-2006. Multivariate regression analyses were performed to evaluate the factors influencing early and late admission.

RESULTS

The median time to hospitalisation was 2 h (mean 6.1, SD 18.7). Within 2 h of onset, 59.8% patients arrived and 20.6% arrived during the 2-6 h interval. A substantial number of patients (19.6%) arrived after 6 h and onwards. A time lag of >2 h in hospital admission was significantly influenced by history of hypertension, angina, presence of syncope as an initial symptom and time of AMI onset. A time lag of >6 h shared similar characteristics except for presence of history of angina.

CONCLUSIONS

About one-fifth of patients with AMI have prolonged time lag in the study population. Future research intervention and health promotion activities should focus on achieving a reduction in presentation delays.

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, 29.7/10(5) 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.

CONCLUSIONS

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.

Lifetime Risk of Stroke in Japan

Background and Purpose— Lifetime risk (LTR) is an epidemiologic measure that expresses the probability of disease in the remaining lifetime for an index age. The LTR for stroke has not been reported for the Japanese population.

Methods— We included all participants from the Suita Study who were cardiovascular disease–free at baseline. Age (in years) was used as the time scale. Age-specific stroke incidence and all-cause mortality were calculated with the person-year method, and we estimated the sex- and index age–specific LTRs of first-ever stroke and its subtypes, taking into account the competing risk of death.

Results— We followed up 5498 participants from 1989 to 2005 for a total of 67 475 person-years. At age 55 years, the LTR for stroke, after accounting for competing risks of death, was 18.3% for men and 19.6% for women. The LTR for cerebral infarction was 14.6% for men and 15.5% for women, and the LTR for intracerebral hemorrhage was 2.4% for men and 1.4% for women at the index age of 55 years. The LTR for stroke remained similar across other index ages of 45, 55, and 65 years.

Conclusions— The observed probabilities illustrate that ≈1 in 5 men and women of middle age will experience stroke in their remaining lifetime. This easy understandable information can be used as an important index to assist in public health education and planning.

Iron intake and associated factors in general Japanese population: NIPPON DATA80, NIPPON DATA90 and national nutrition monitoring

OBJECTIVE

The purpose of this study was to investigate the dietary iron intake and associated other dietary factors and clinical characteristics among a representative sample cohort of Japanese population.

METHODS

We obtained data from NIPPON DATA80 and 90 that were conducted with the National Nutrition Surveys in 1980 and in 1990. Then we estimated nutrient and food intakes of individuals in the National Nutrition Survey of 1980 and that of 1990, which were adjusted on the basis of data of the National Nutrition Survey of 1995. Finally, we analyzed data for the 10,422 participants (4585 men and 5837 women) in NIPPON DATA80 and 8342 participants (3488 men and 4854 women) in NIPPON DATA90 having dietary iron intake information.

RESULTS

In NIPPON DATA80 and 90, there was a significant relationship between the dietary iron intake and age for both men and women. Dietary protein intake was associated with iron intake where as dietary fat intake did not show any association. Regarding the minerals, significant relationships were observed between the different minerals and dietary iron intake. Apart from the food group of milk and dairy products, there were significant differences in other food groups according to quintiles of iron intakes for men and women.

CONCLUSIONS

We described the mean dietary iron intake and its relation with other dietary factors and clinical characteristics in Japanese adults as the baseline data in NIPPON DATA80 and in NIPPON DATA90.

Circaseptan variation in case-fatality rate for patients with acute subarachnoid hemorrhage (Takashima Stroke Registry 1988-2003)

We explored the circaseptan variation in 28-day case-fatalities for patients with subarachnoid hemorrhage (SAH) across days of the week. Data were obtained from the Takashima Stroke Registry, which covers approximately 50000 residents of central Japan. There were 169 first-ever SAH cases registered during the period 1988-2003 (68 in males, 101 in females). We divided the SAH cases into two groups according to the day on which the SAH occurred: "weekend" and "weekday". The 28-day case-fatality rate and 95% confidence interval (CI) were calculated. Multiple logistic regression analysis was used to calculate the adjusted odds ratio (95% CI) for weekday fatalities by entering all relevant patient-level variables into the model. The 28-day case-fatality rate for SAH was higher on weekdays (51.7%) than on weekends (32.6%; odds ratio 2.19; 95% CI: 1.10-4.49). The differences in fatality rate persisted after adjustment for age, sex, severity, family history of stroke and patient history of hypertension, diabetes mellitus, dyslipidemia, drinking and smoking. We observed a circaseptan variation in fatalities from SAH, with higher fatality rates during weekdays in our study population.

Dietary intake of potassium and associated dietary factors among representative samples of Japanese general population: NIPPON DATA 80/90

OBJECTIVE

The purpose of this study was to investigate the dietary potassium intake and associated other dietary factors among a representative sample cohort of Japanese population.

METHODS

We obtained data from NIPPON DATA80 and 90 that were conducted with the National Nutrition Surveys in 1980 and in 1990. Then we estimated nutrient and food intakes of individuals in the National Nutrition Survey of 1980 and that of 1990, which were adjusted on the basis of data of the National Nutrition Survey of 1995. We analyzed data for 10,422 participants (4585 men and 5837 women) in NIPPON DATA80 and 8342 participants (3488 men and 4854 women) in NIPPON DATA90 having dietary potassium intake information.

RESULTS

In NIPPON DATA80 and 90 it was observed that there was a significant relationship between the dietary potassium intake and age for both men and women. Higher potassium intake was associated with higher age, intake of protein, iron, calcium, sodium, vitamins, and fiber. Regarding food groups, lower amount of dietary cereals, rice, flour, fats and oils were associated with higher dietary potassium for both men and women. On the other hand, higher intake of nuts, potatoes, soy beans, fruits, vegetables, mushrooms, sea algae, fish and shellfish were associated with higher dietary potassium.

CONCLUSIONS

We obtained the mean dietary potassium intake and its association with other dietary nutrient intake in Japanese adults as the baseline data in NIPPON DATA80 and in NIPPON DATA90.

Diurnal variation in onset of hemorrhagic stroke is independent of risk factor status: Takashima Stroke Registry

BACKGROUND

We examined the circadian periodicity of hemorrhagic stroke onset to identify any existing specific pattern and its relationship with conventional stroke risk factors using 14-year stroke registration data.

METHODS

Data were obtained from the Takashima Stroke Registry, which covers a stable population of approx. 55,000 in Takashima County in central Japan. Out of 499 registered first-ever hemorrhagic stroke events during 1990-2003, there were 429 (186 men, 243 women) events with classifiable onset time. Hemorrhagic stroke incidence was categorized as occurring at night (midnight to 6 a.m.), morning (6 a.m. to noon), afternoon (noon to 6 p.m.) or evening (6 p.m. to midnight). The OR (with 95% CI) of having a stroke in the morning, afternoon or evening were calculated, with night serving as reference.

RESULTS

There was significant diurnal variation in hemorrhagic stroke incidence (p < 0.001). The proportion of hemorrhagic strokes was highest in the morning (36.1%, 95% CI: 31.7-40.8) and lowest in the night (11.9%, 95% CI: 9.1-15.3). An excess stroke incidence in the morning was observed in both genders, in subjects < 65 years and > or =65 years, and in both intracerebral hemorrhage and subarachnoid hemorrhage. A second surge was also observed during the later part of the day. The higher daytime risk persisted after adjusting for age, gender, and risk factors.

CONCLUSION

In the examination of circadian variation of hemorrhagic stroke onset, a 2-peak temporal distribution was observed, which was independent of conventional risk factors.

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.

Trend of increase in the incidence of acute myocardial infarction in a Japanese population: Takashima AMI Registry, 1990-2001

The incidence and mortality of acute myocardial infarction (AMI) remain low in Japan despite major dietary changes and worsening cardiovascular risk factors, a situation that should have resulted in a substantial increase in AMI rates (Japanese paradox). The current trend in the incidence of AMI was examined for the period 1990-2001 by use of data from the Takashima AMI Registry covering a stable population of approximately 55,000 in central Japan. AMI incidence rates (per 100,000 person-years) and 95% confidence intervals were calculated for 1990-1992, 1993-1995, 1996-1998, and 1999-2001. The incidence trend was determined by calculating the average annual change in percentage across the years. There were 352 (men: n = 224; women: n = 128) registered first-ever AMI cases during 1990-2001. The age-adjusted incidence rate of all AMI showed a gradual increase from 39.9 (95% confidence interval (CI): 29.8, 50.0) in 1990-1992 to 62.6 (95% CI: 51.5, 73.7) in 1999-2001. In men, the age-adjusted incidence rate increased from 66.5 (95% CI: 46.4, 86.6) in 1990-1992 to 100.7 (95% CI: 78.6, 122.7) in 1999-2001. In women, fluctuation was observed after an initial steep increase. The average annual incidence increased by 7.6% (95% CI: 3.5, 11.7) among men and by 8.3% (95% CI: 1.02, 15.6) among women. To the best of the authors' knowledge, this is the first study to report an increasing trend of AMI in a Japanese population.

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.

Registration and Surveillance of Acute Myocardial Infarction in Japan: Monitoring an Entire Community by the Takashima AMI Registry System and Design

BACKGROUND

The purpose of this registration is to follow incidence and case fatality trend of acute myocardial infarction (AMI) in Japan, using a whole community population disease registry that surveys the most up-to-date information. Since the 1970s, mortality from coronary heart disease has followed a declining trend in Japan, which has been attributed to a decrease in the incidence of AMI and some evidence suggests that incidence has leveled off during the past couple of decades. These reported decreasing or stable trends in AMI have been observed despite recent worsening of the cardiovascular risk factor situation in Japan (Japanese paradox). Therefore, monitoring the disease course of AMI is of immense importance.

METHODS AND RESULTS

The Takashima AMI Registry established in 1988 covers a stable population of approximately 55,000 in Takashima County in central Japan. Registered patients included all Takashima County residents who have been diagnosed with AMI. The criteria of AMI are in accord with those of the World Health Organization's Monitoring of Trends and Determinants in Cardiovascular Disease (WHO-MONICA) project.

CONCLUSION

Comprehensive disease registry data is especially appropriate for determining the incidence as well as the trend of diseases such as AMI. This registration study covering an entire community will enable researchers to follow trends in AMI incidence with a high degree of precision.