Heart disease deaths on death certificates re-evaluated by clinical records in a Japanese city

Impact of Cardiovascular Disease on the Death Certificate Diagnosis of Heart Failure, Ischemic Heart Disease, and Cerebrovascular Disease - The Japan Public Health Center-Based Prospective Study

BACKGROUND

There is considerable interest in the trending discrepancy between ischemic heart disease (IHD) and heart failure (HF) in vital statistics. Clinically, acute myocardial infarction (AMI) and stroke are closely associated with HF, but their contribution to HF as the underlying cause of death (UCD) is unclear.Methods and Results: In 1990 and 1992-1993, we enrolled a total of 140,420 residents of Japanese nationality (aged 40-69 years) from 11 public health center areas. We prospectively examined the occurrence of cardiovascular disease (CVD), including AMI, sudden cardiac death within 1 h (SCD), and stroke, and analyzed the 14,375 participants without a history of CVD at baseline who died during the 20-year follow-up. A time-dependent Cox proportional hazards model was used to estimate hazard ratios and the population attributable fraction (PAF) of AMI, AMI+SCD, stroke, and CVD for deaths due to HF, IHD, and cerebrovascular disease as the UCD, adjusted for individuals' lifestyles and comorbid conditions. The PAF of AMI for HF deaths was 2.4% (95% confidence interval [CI] 1.7-2.9%), which increased to 12.0% (95% CI 11.6-12.2%) for AMI+SCD. The PAF of CVD-attributed HF deaths was estimated to be 17.6% (95% CI 15.9-18.9%).

CONCLUSIONS

HF as the UCD was partly explained by CVD. The data imply that most HF deaths reported in vital statistics may be associated with underlying causes other than CVD.

Effect of age-related baseline risk on radiation dose response for coronary heart disease

We attempted to estimate the mortality risk of radiation-associated coronary heart disease (CHD) by using a model in which radiation was assumed to participate in the atherosclerotic process jointly with ageing. Model parameters were determined by fitting the Life Span Study data of atomic bomb survivors. According to the model, the excess relative risk (ERR) varies depending on the baseline risk; when applied to the death statistics of Japan and the USA, the estimated ERR was consistently higher in the Japanese population. The absolute risk showed an opposite trend, such that the estimated lifetime attributable risk was approximately two times higher in the US population. Excess cases were expected to appear in old age almost synchronously with spontaneous cases; in contrast, the risk is practically unnoticeable for those young to middle aged. Our model suggests that the radiation dose-response curve for CHD, as well as the latency in epidemiological studies, could be modified by the baseline risk.

Relationship Between Dietary Vitamin D and Deaths From Stroke and Coronary Heart Disease: The Japan Collaborative Cohort Study

BACKGROUND AND PURPOSE

There is growing evidence about the importance of vitamin D for cardiovascular health. Therefore, we examined the relationship between dietary vitamin D intake and risk of mortality from stroke and coronary heart disease in Japanese population.

METHODS

A prospective study encompassing 58 646 healthy Japanese adults (23 099 men and 35  547 women) aged of 40 to 79 years in whom dietary vitamin D intake was determined via a self-administered food frequency questionnaire. The median follow-up period was 19.3 years (1989-2009). The hazard ratios and 95% confidence intervals of mortality were calculated using categories of vitamin D intake.

RESULTS

During 965 970 person-years of follow-up, 1514 stroke and 702 coronary heart disease deaths were documented. Vitamin D intake was inversely associated with risk of mortality from total stroke especially intraparenchymal hemorrhage but not from coronary heart disease; the multivariable hazard ratios (95% confidence intervals) for the highest (≥440 IU/d) versus lowest (<110 IU/D) categories of vitamin D intake were 0.70 (0.54-0.91; P for trend=0.04) for total stroke and 0.66 (0.46-0.96; P for trend=0.04) for intraparenchymal hemorrhage.

CONCLUSIONS

Dietary vitamin D intake seems to be inversely associated with mortality from stroke.

Television viewing time and mortality from stroke and coronary artery disease among Japanese men and women -- the Japan Collaborative Cohort Study

BACKGROUND

No study has examined the association between television (TV) viewing time and mortality from stroke and coronary artery disease (CAD) in Japanese.

METHODS AND RESULTS

A total of 35,959 men and 49,940 women aged 40-79 years without a history of cardiovascular disease (CVD) and cancer were followed from 1988-1990 until 2009. During 19.2 median years of follow-up, there were 2,553 deaths from stroke, 1,206 from CAD and 5,835 from total CVD. Compared with viewing TV for <2 h/day, mortality from stroke, CAD and total CVD were higher for ≥6 h/day of TV viewing. The multivariable hazard ratios (HRs) for ≥6 h/day of TV viewing were 1.15 (95% confidence interval: 0.96-1.37) for stroke, 1.33 (1.03-1.72) for CAD and 1.19 (1.06-1.34) for total CVD. The corresponding HRs for each 1-h/day increment in TV viewing time were 1.01 (0.99-1.04), 1.04 (1.01-1.08) and 1.02 (1.01-1.04), respectively. The excess risk of mortality from CAD and total CVD was somewhat attenuated after further adjustment for potential mediators such as history of hypertension and diabetes: the multivariable HRs for ≥6 h/day of TV viewing were 1.24 (0.96-1.61) and 1.14 (1.02-1.28). The corresponding HRs for each 1-h/day increment in TV viewing time were 1.03 (1.00-1.07) and 1.01 (1.00-1.03).

CONCLUSIONS

Prolonged TV viewing was associated with a small but significant increase in mortality from CAD and total CVD in Japanese.

Cellular growth factors in relation to mortality from cardiovascular disease in middle-aged Japanese: the JACC study

OBJECTIVE

Limited evidence has been available on the relationships of cellular growth factors with cardiovascular disease in population-based samples.

METHODS

We conducted a nested case-control study under a large prospective cohort study (JACC study) where a total of 39,242 subjects aged 40-79 years provided serum sample. We measured cellular growth factors [insulin-like growth factors I, II and binding protein-3 (IGF-I, IGF-II and IGFBP-3) and transforming growth factor (TGF-β1)] among cases and controls, matched for sex, age, area of residence and year of serum storage.

RESULTS AND CONCLUSIONS

During the follow-up for 9 years, there were 233 deaths from total stroke (49 subarachnoid hemorrhages, 55 intraparenchymal hemorrhages, 71 ischemic strokes), and 97 deaths from coronary heart disease. The multivariable odds ratio (95%CI) of intraparenchymal hemorrhage associated with a 1-SD increment of IGF-I (men:4 8 ng/ml, women: 61 ng/ml) was 0.31 (0.14-0.71). That of ischemic stroke associated with a 1-SD increment of TGF-β1 (men: 8.0 ng/ml, women: 10.9 ng/ml) was 0.58 (0.34-0.98). Serum IGF-II and IGFBP-3 were not associated with mortality from any outcomes. In conclusion, IGF-I was inversely associated with mortality from intraparenchymal hemorrhage while TGF-β1 was so with ischemic stroke, suggesting potential roles of cellular proliferation in the development or prognosis of stroke.

Relation of serum α- and γ-tocopherol levels to cardiovascular disease-related mortality among Japanese men and women

Background

There is limited evidence regarding the relationship between serum tocopherol levels and cardiovascular disease.

Methods

We conducted a nested case-control study as part of the Japan Collaborative Cohort Study for evaluation of cancer risk (JACC Study). Baseline serum samples were collected from 39 242 participants (age range, 40–79 years) between 1988 and 1990. During the 13-year follow-up, there were 530 stroke deaths (302 ischemic strokes and 210 hemorrhagic strokes) and 211 deaths from coronary heart disease. Controls were matched for sex, age, and area of residence.

Results

Serum α-tocopherol level was not associated with any type of cardiovascular death in men; however, in women, it was inversely associated with total stroke mortality and hemorrhagic stroke mortality. The multivariate odds ratio (95% CI) for the highest versus the lowest quintile of serum α-tocopherol levels among women was 0.35 (0.16–0.77; P for trend = 0.009) for total stroke and 0.26 (0.07–0.97; P for trend = 0.048) for hemorrhagic stroke. Serum γ-tocopherol was inversely associated with ischemic stroke mortality in men but positively associated with hemorrhagic stroke mortality in women. The respective multivariate odds ratios (95% CI) for the highest versus the lowest quintile and for a 1-standard deviation increment in γ-tocopherol level were 0.48 (0.22–1.06; P for trend = 0.07) and 0.77 (0.58–1.02), respectively, for ischemic stroke in men and 3.10 (0.95–10.12; P for trend = 0.052) and 1.49 (1.04–2.13) for hemorrhagic stroke in women.

Conclusions

Among women, hemorrhagic stroke mortality was inversely associated with serum α-tocopherol and positively associated with serum γ-tocopherol. These findings are due in part to the antioxidative and antithrombotic activities of these tocopherols.

Salt preference and mortality from stroke and coronary heart disease for Japanese men and women: the JACC study

OBJECTIVE

The study aims to examine the association between salt preference and mortality from stroke and coronary heart disease (CHD).

METHODS

Between 1988 and 1990, 35515 men and 49275 women aged 40-79 years completed a self-administered questionnaire in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk sponsored by Monbusho. During a median duration of 16.4 years, 1970 stroke and 922 CHD deaths were observed. Salt preference was divided into three groups: low, moderate and high.

RESULTS

Mortality rates per 1000 person-year from stroke were 2.0 for men, 1.3 for women and 1.6 for total subjects. The respective mortality from CHD was 1.1, 0.5 and 0.8, and that from total cardiovascular disease was 4.6, 2.9 and 3.6. Salt preference was positively associated with mortality from stroke for both sexes. The multivariable hazard ratios of stroke mortality for high versus low salt preference were 1.21(0.99-1.49) for men, 1.22(1.00-1.49) for women and 1.23(1.06-1.41) for total subjects. That positive association was primarily observed among male heavy drinkers (≥ 46.0 g ethanol/day). Salt preference tended to be inversely associated with mortality from CHD.

CONCLUSION

Salt preference was associated with increased mortality from stroke for both sexes, particularly for male heavy drinkers.

Mild retinopathy is a risk factor for cardiovascular mortality in Japanese with and without hypertension: the Ibaraki Prefectural Health Study

BACKGROUND

It is unclear whether mild hypertensive retinopathy is a risk factor for mortality. This study examined whether mild hypertensive retinopathy could be a risk factor for cardiovascular mortality in subjects with and without hypertension.

METHODS AND RESULTS

In this cohort study, 87 890 individuals (29 917 men and 57 973 women) 40 to 79 years of age in 1993 were followed up until 2008. Retinal photography was classified as normal, grade 1, or grade 2 based on the Keith-Wagener-Barker system. Risk ratios for all-cause and cause-specific mortality for each classification were calculated with Cox proportional hazards regression models. Covariates included age, systolic blood pressure, antihypertensive medication use, and other cardiovascular risk factors. Multivariable hazard ratios for total cardiovascular disease mortality were 1.24 (95% confidence interval [CI], 1.12-1.38) and 1.23 (95% CI, 1.03-1.47) for grades 1 and 2 among men and 1.12 (95% CI, 1.01-1.24) and 1.44 (95% CI, 1.24-1.68) for grades 1 and 2 among women, respectively. Hazard ratios for total stroke mortality were 1.31 (95% CI, 1.13-1.53) and 1.38 (95% CI, 1.08-1.77) for grades 1 and 2 among men and 1.30 (95% CI, 1.12-1.50) and 1.70 (95% CI, 1.36-2.11) for grades 1 and 2 among women, respectively. For both hypertensive and normotensive subjects of each sex, multivariable hazard ratios for all-cause mortality, total cardiovascular mortality, and total stroke mortality were significantly higher for grade 1 or 2 compared with normal.

CONCLUSIONS

Mild hypertensive retinopathy is a risk factor for cardiovascular mortality independently of cardiovascular risk factors among men and women with and without hypertension.

Deaths from heart failure: using coarsened exact matching to correct cause-of-death statistics

Background

Incomplete information on death certificates makes recorded cause-of-death data less useful for public health monitoring and planning. Certifying physicians sometimes list only the mode of death without indicating the underlying disease or diseases that led to the death. Inconsistent cause-of-death assignment among cardiovascular causes of death is of particular concern. This can prevent valid epidemiologic comparisons across countries and over time.

Methods

We propose that coarsened exact matching be used to infer the underlying causes of death where only the mode of death is known. We focus on the case of heart failure in US, Mexican, and Brazilian death records.

Results

Redistribution algorithms derived using this method assign the largest proportion of heart failure deaths to ischemic heart disease in all three countries (53%, 26%, and 22% respectively), with larger proportions assigned to hypertensive heart disease and diabetes in Mexico and Brazil (16% and 23% vs. 7% for hypertensive heart disease, and 13% and 9% vs. 6% for diabetes). Reassigning these heart failure deaths increases the US ischemic heart disease mortality rate by 6%.

Conclusions

The frequency with which physicians list heart failure in the causal chain for various underlying causes of death allows for inference about how physicians use heart failure on the death certificate in different settings. This easy-to-use method has the potential to reduce bias and increase comparability in cause-of-death data, thereby improving the public health utility of death records.

Association between non-high-density lipoprotein cholesterol concentrations and mortality from coronary heart disease among Japanese men and women: the Ibaraki Prefectural Health Study

AIM

The aim of this study was to examine whether non-high-density lipoprotein cholesterol (non-HDL-cholesterol) raises the risk of coronary heart disease in a dose-response fashion in a non-obese population with low total cholesterol levels and high HDL-cholesterol levels, such as Japanese.

METHODS

A total of 30,802 men and 60,417 women, aged 40 to 79 years with no history of stroke or coronary heart disease, completed a baseline risk factor survey in 1993 under the auspices of the Ibaraki Prefectural Health Study. Systematic mortality surveillance through 2003 identified 539 coronary heart disease deaths.

RESULTS

The mean values for non-HDL-cholesterol were 140 mg/dL for men and 151 mg/dL for women. The corresponding mean values were 193 mg/dL and 208 mg/dL total cholesterol and 52 mg/dL and 57 mg/dL HDL-cholesterol, respectively. Men with non-HDL-cholesterol > or = 180 mg/dL had a two-fold higher age-adjusted risk of mortality from coronary heart disease than did those with non-HDL-cholesterol <100 mg/dL, whereas no such association was found for women. The multivariable hazard ratio for > or = 180 mg/dL versus <100 mg/dL of non-HDL-cholesterol was 2.22 (95% confidence interval: 1.37 to 3.62) for men and 0.71 (0.37 to 1.34) for women.

CONCLUSION

Higher concentrations of non-HDL-cholesterol were associated with an increased risk of mortality from coronary heart disease for men, but not for women.

Associations between metabolic syndrome and mortality from cardiovascular disease in Japanese general population, findings on overweight and non-overweight individuals. Ibaraki Prefectural Health Study

BACKGROUND

The impact of being overweight, as a component of the metabolic syndrome (MetS), for cardiovascular disease (CVD) mortality was investigated and compared with the predictive value of MetS by 2 different definitions.

METHODS AND RESULTS

A 12-year prospective study of 30,774 Japanese men and 60,383 women aged 40-79 years was conducted. The multivariate hazard ratio (HR; 95% confidence interval) of total CVD mortality for overweight subjects with >or=2 additional risk factors with reference to subjects with 0 of 4 MetS components was 1.83 (1.41-2.38) for men and 1.90 (1.45-2.49) for women, and for non-overweight subjects with >or=2 additional risk factors 1.75 (1.38-2.24) and 1.97 (1.52-2.55), respectively. The proportion of excess CVD deaths in the latter group was 1.5-fold higher than that in the former group. Multivariate HRs of coronary heart disease and total CVD mortality for MetS by the modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute were 1.62 (1.31-2.00) and 1.23 (1.09-1.39), respectively, for men and 1.32 (1.05-1.65) and 1.12 (1.00-1.25), respectively, for women. The respective HRs for MetS by the International Diabetic Federation definition did not reach statistical significance, except for coronary heart disease in men.

CONCLUSIONS

Non-overweight individuals with metabolic risk factors, as well as overweight individuals with such factors, should be targeted to reduce the CVD burden in the general population.

C-reactive protein levels and risk of mortality from cardiovascular disease in Japanese: the JACC Study

OBJECTS

Limited evidence of association between C-reactive protein levels and cardiovascular disease has been produced for Japanese whose median protein levels are low by western standards.

METHODS

We conducted a nested case-control study as part of the Japan Collaborative Cohort Study for evaluation of cancer risk (JACC Study). A total of 39,242 subjects 40-79 years of age provided serum samples at baseline between 1988 and 1990. During the 13-year follow-up, there were 525 deaths from total strokes (ICD10: I60-I69), 209 coronary heart diseases (I20-I25) and 939 total cardiovascular diseases (I00-I99). The control subjects were matched for sex, age, area of residence and year of serum storage, and analyses were conducted after further adjustment for cardiovascular risk factors. Serum high-sensitivity C-reactive protein (hs-CRP) levels were measured with ultra-sensitive latex-enhanced immunoassay.

RESULTS

Median hs-CRP levels for controls were 0.40 mg/L for men and 0.41 mg/L for women. Hs-CRP levels were positively associated with risks of mortality from stroke, coronary heart disease, and total cardiovascular disease for men. The respective multivariable odds ratios (OR 95% CI) for the highest (>or=0.85 mg/L) vs. lowest (<0.19 mg/L) quartiles of hs-CRP for men were 1.60 (0.90-2.85), 3.68 (1.02-13.3), and 2.31 (1.49-3.59). For women, positive associations with hs-CRP levels were weaker, reaching statistical significance only for total cardiovascular disease: OR=1.69 (1.06-2.68). The positive association with total cardiovascular disease did not vary according to sex, age, smoking status, or body mass index.

CONCLUSIONS

Higher serum hs-CRP levels were associated with higher mortality from cardiovascular disease in Japanese.

Association of sleep duration with mortality from cardiovascular disease and other causes for Japanese men and women: the JACC study

STUDY OBJECTIVES

To examine sex-specific associations between sleep duration and mortality from cardiovascular disease and other causes.

DESIGN

Cohort study.

SETTING

Community-based study.

PARTICIPANTS

A total of 98,634 subjects (41,489 men and 57,145 women) aged 40 to 79 years from 1988 to 1990 and were followed until 2003.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

During a median follow-up of 14.3 years, there were 1964 deaths (men and women: 1038 and 926) from stroke, 881 (508 and 373) from coronary heart disease, 4287 (2297 and 1990) from cardiovascular disease, 5465 (3432 and 2033) from cancer, and 14,540 (8548 and 5992) from all causes. Compared with a sleep duration of 7 hours, sleep duration of 4 hours or less was associated with increased mortality from coronary heart disease for women and noncardiovascular disease/noncancer and all causes in both sexes. The respective multivariable hazard ratios were 2.32 (1.19-4.50) for coronary heart disease in women, 1.49 (1.02-2.18) and 1.47 (1.01-2.15) for noncardiovascular disease/noncancer, and 1.29 (1.02-1.64) and 1.28 (1.03-1.60) for all causes in men and women, respectively. Long sleep duration of 10 hours or longer was associated with 1.5- to 2-fold increased mortality from total and ischemic stroke, total cardiovascular disease, noncardiovascular disease/noncancer, and all causes for men and women, compared with 7 hours of sleep in both sexes. There was no association between sleep duration and cancer mortality in either sex.

CONCLUSIONS

Both short and long sleep duration were associated with increased mortality from cardiovascular disease, noncardiovascular disease/noncancer, and all causes for both sexes, yielding a U-shaped relationship with total mortality with a nadir at 7 hours of sleep.

Alcohol consumption and mortality from stroke and coronary heart disease among Japanese men and women: the Japan collaborative cohort study

BACKGROUND AND PURPOSE

Previous studies have demonstrated the association between alcohol consumption and cardiovascular mortality. However, the sex-specific association between alcohol consumption and mortality from stroke and coronary heart disease remains unclear.

METHODS

Between 1988 and 1990, 34,776 men and 48 906 women aged 40 to 79 years completed a self-administered questionnaire including information about alcohol consumption. They were followed-up for a median duration of 14.2 years.

RESULTS

Of the 83,682 respondents, 1628 died from stroke and 736 died from coronary heart disease. For men, heavy drinking (>or=46.0 g ethanol/day) was associated with increased mortality from total, hemorrhagic, and ischemic strokes, whereas light-to-moderate drinking was associated with reduced mortality from total cardiovascular disease, compared with not drinking. The respective multivariable hazard ratios (95% CI) were 1.48 (1.22 to 1.80) for total stoke, 1.67 (1.17 to 2.38) for hemorrhagic stroke, 1.35 (1.04 to 1.75) for ischemic stroke, and 0.88 (0.78 to 1.00) for total cardiovascular disease. Women who were heavy drinkers (>or=46.0 g ethanol/day) showed increased mortality from coronary heart disease, and there was reduced mortality from total cardiovascular disease for drinkers of 0.1 to 22.9 g ethanol per day compared with mortality for nondrinkers. The respective multivariable hazard ratios (95% CI) for the 2 categories of drinkers were 4.10 (1.63 to 10.3) and 0.75 (0.62 to 0.91).

CONCLUSIONS

Heavy alcohol consumption is associated with increased mortality from total stroke, particularly hemorrhagic stroke, and total cardiovascular disease for men, and from coronary heart disease for women, whereas light-to-moderate drinking may be associated with reduced mortality from cardiovascular disease for both sexes.

Explanation for the Japanese paradox: prevention of increase in coronary heart disease and reduction in stroke

Japan's age-adjusted rate for mortality from stroke increased after the Second World War until 1965 and then showed a significant decline until 1990; however, the age-adjusted rate for mortality from all heart disease and coronary heart disease (CHD) increased until 1970 and then declined slowly. A puzzling question is why the rate of mortality from CHD declined in spite of an increase in serum total cholesterol level following an increase in fat consumption. It was confirmed that CHD incidence was far lower in several Japanese populations compared to Western countries in the " Monitoring Trends and Determinants in Cardiovascular Disease " (MONICA) project; therefore, the lower CHD mortality in Japan stems from the lower CHD incidence. CHD risk factors based on epidemiologic cohort studies in Japan were no different from those of other industrialized countries: hypertension, hypercholesterolemia, smoking and diabetes mellitus (DM). So, how can we explain this phenomenon?There are three possible explanations. One is the decline in population blood pressure level and the prevalence of hypertension during the years 1965-1990; the second is the decline in smoking rate in men and women; the third is that the serum total cholesterol level for middle-aged and elderly populations remains 5-15 mg/dL lower than that of the US elderly counterpart, although men aged 40-49 in Japan and the US had similar serum total cholesterol levels. It was also noted that elderly people in Japan, as observed in the Seven Countries Study, had far lower serum total cholesterol levels in midlife, i.e., around 160 mg/dL in the 1960s. This was not the case for elderly in the US where a higher serum total cholesterol level was observed in midlife. In conclusion, the lower serum cholesterol level in the past of Japanese middle-aged and elderly people compared to Western counterparts helps to maintain the low CHD incidence and mortality supported by the declining trend in blood pressure level and smoking rate for both men and women.

Resting heart rate and cause-specific death in a 16.5-year cohort study of the Japanese general population

BACKGROUND

Several prospective studies have reported resting heart rate (HR) to be a risk factor for certain cause-specific death, together with sex- or age-specific differences in the effects of HR on death. However, there have been few prospective data from non-Western populations.

METHODS

Cohort study, over 16.5 years to date of death or end of follow-up (November 15, 1998) involving 8800 men and women > or =30 years of age randomly selected throughout Japan, who participated in the National Survey on Circulatory Disorders in 1980. Resting HR was determined from 3 consecutive intervals between R waves on the 12-lead electrocardiogram.

RESULTS

For middle-aged men (30 to 59 years of age), in the highest quartile of HR, there was a significant positive association with cardiovascular (RR, 2.55; 95% CI, 1.22 to 5.31) and all-cause death (RR, 1.45; 95% CI, 1.06 to 2.00). For middle-aged women, in the highest quartile, there was a significant positive association with noncancer, noncardiovascular (RR, 2.41; 95% CI, 1.04 to 5.59), and all-cause death (RR, 1.94; 95% CI, 1.26 to 3.01). Resting HR also showed a significant positive association with cardiac events but not to stroke. These relations were not evident for elderly subjects (> or =60 years of age). Results were not affected when deaths within the first 5 years of follow-up were excluded, except for noncancer, noncardiovascular death.

CONCLUSIONS

High resting HR is an independent predictor of long-term death in the Japanese general population.

Trends in fatal coronary heart disease among people aged 25-74 years in Oita City, Japan, from 1987-1998

Serum cholesterol has been increasing in recent years in Japan. There is concern that risk of coronary heart disease (CHD) may be increasing too, but there is little information on validated fatal CHD trends in the Japanese population. We identified 1,056 deaths from heart disease and other deaths possibly hiding CHD from death certificates of residents aged 25-74 years in Oita City, Japan in 1987-1988, 1992-1993, and 1997-1998 (mean population, 273,000 in 1997-1998). We validated 994 of them by medical record review and physician interviews, classifying them into definite fatal acute myocardial infarction (AMI) and possible fatal AMI or CHD death based on Monitoring Trends and Determinants in Cardiovascular Disease project's criteria. Sudden death was defined to estimate the number of CHD sudden deaths. In men, age-adjusted mortality rates due to validated fatal CHD remained quite stable over 10 years (25.3 per 100,000 [95% CI, 15.0-35.5] in 1987-1988 to 24.2 per 100,000 [95% CI, 16.1-32.3] in 1997-1998). When 50% or all sudden deaths were included as fatal CHD, the rates for men tended to decline. This was due to decreasing out-of-hospital deaths in connection with a declining CHD death rate among men aged 65-74 years, whereas in-hospital CHD deaths were level. In women, the rate of validated fatal CHD was highest in 1992-1993, but the 1997-1998 rate was similar to the 1987-1988 rate. We did not find that fatal CHD rates increased in Oita men and women from 1987-1998. Rather, out-of-hospital fatal CHD tended to decline in Oita men.

Comparison of fatal coronary heart disease occurrence based on population surveys in Japan and the USA

BACKGROUND

Although vital statistics have indicated large Japanese-American differences in mortality rates for coronary heart disease (CHD), the magnitude of difference has not been documented well using comparable validation of cause of death.

METHODS

Population-based fatal CHD data were compared between the Oita Cardiac Death Survey, Japan and the Atherosclerosis Risk in Communities (ARIC) Study, USA. Both studies (population: Oita City 198 093; the ARIC comunities 286 820) identified possible fatal CHD events (International Classification of Diseases, Ninth Revision [ICD-9]: 410-414, 250, 401-402, 427-429, 440, and 798-799) among residents aged 35-74 years during 1992-1993. Comparable criteria for classifying cause of death were applied. Sex-specific, age-adjusted mortality rates of CHD were calculated by place of death.

RESULTS

In all, 330 deaths in Oita and 1398 in the ARIC communities had eligible ICD-9 death certificate codes; CHD codes (ICD-9 410-414) comprised 30.6% of investigated deaths in Oita and 58.6% in ARIC. For men, the non-validated rate ratio for CHD deaths (ARIC:Oita City) was 5.9 (95% CI : 4.2-8.5), which fell to 4.7 (95% CI : 3.5-6.4) with validation and inclusion of sudden deaths within one hour of onset as fatal CHD. For women, the overall non-validated rate ratio was 4.6 (95% CI : 2.8-7.6), which fell to 3.9 (95% CI : 2.4-6.3) with validation and but there was little further change when the sudden deaths were added.

CONCLUSIONS

Our results suggest that differences in fatal CHD rates between Japanese and Americans were not as large as suggested by vital statistics when events were validated and sudden deaths were included.

Analysis of the treatment of acute myocardial infarction using ambulance records in Japanese cities

By means of ambulance records, the current state of medical services for the treatment of acute myocardial infarction (AMI) was investigated in Chiba City and Ichihara City, Japan. From all patients transported by ambulance personnel in 1992 (n=31,191), 388 patients who were admitted within 2 weeks after the onset were studied. Types of admitting institution, diagnoses, medical treatments and prognoses were investigated. According to medical records, 168 patients fulfilled the criteria of definite AMI and were admitted alive. Percutaneous transluminal coronary angioplasty (PTCA) and recanalization (PTCR) were performed on 54 and 6 patients, respectively. The hospital case-fatality rates were lower in the patients who underwent emergency PTCA or PTCR than in the others. Emergency PTCA or PTCR, and admission to coronary care units (CCU) or institutions equipped with coronary angiography, decreased the fatality risk, even after considering age, sex, and disease severity. These results show the importance of the selection of institutions for AMI patients. Because 40% of definite AMI patients were sent to institutions without CCU, it is essential that enough CCU are available through an improvement in cooperation between the various types of institutions, and in the proper transfer of AMI patients to CCU