[Incidence rate of acute myocardial infarction in Hokkaido, Japan]

Epidemiology of cardiovascular disease in Japan: An overview study

Cardiovascular diseases (CVDs), such as heart disease and stroke, have a significant impact on life expectancy, healthy life expectancy, and medical costs in Japan. Each prefecture is currently promoting measures in accordance with the Japanese National Plan for Promotion of Measures Against Cerebrovascular and Cardiovascular Disease, which was established by the government. In recent years, the crude mortality rate of heart disease in Japan has been increasing year by year with the aging population. Meanwhile, the age-adjusted mortality rate has leveled off or shown a downward trend. In addition, the proportion of acute myocardial infarction has decreased, whereas the proportion of heart failure has increased. By contrast, both the crude and age-adjusted mortality rates of stroke have a declining trend. Nevertheless, considering the potential variations in death certificates issued for patients with myocardial infarction across different prefectures, it is crucial to determine the incidence of CVD in each prefecture for the accurate assessment of CVD trends. However, as for the incidence of CVD, not many prefectures have yet implemented registration programs. The age-adjusted incidence rate of acute myocardial infarction has been increasing in some areas and decreasing in others since 1990. The age-adjusted incidence rate of stroke has consistently declined since the 1960s. Nevertheless, the possible increase in the incidence rate of cerebral embolism and thrombotic cerebral infarction among patients with different stroke subtypes is a cause of concern. The impact of heart failure on the incidence of heart disease has increased. Therefore, relevant academic societies and prefectures must collaborate in registering the incidence of heart failure as well as myocardial infarction and implementing countermeasures.

Detection of carotid atherosclerosis in individuals with masked hypertension and white-coat hypertension by self-measured blood pressure at home: The Ohasama Study

OBJECTIVE

To investigate carotid atherosclerosis in individuals with masked hypertension (MHT) and white-coat hypertension (WCHT) in a general population.

METHODS

Self-measurement of blood pressure at home (HBP) and casual blood pressure (CBP) measurements were recorded in 812 individuals aged at least 55 years (mean 66.4 years) from the general Japanese population. The intima-media thickness (IMT) of the near and far wall of both common carotid arteries was measured and averaged. The relationships between carotid atherosclerosis (IMT and plaque) and the four blood pressure groups (sustained normal blood pressure: HBP < 135/85 mmHg, CBP < 140/90 mmHg; WCHT: HBP < 135/85 mmHg, CBP >or= 140/90 mmHg; MHT: HBP >or= 135/85 mmHg, CBP < 140/90 mmHg; sustained hypertension: HBP >or= 135/85 mmHg, CBP >or= 140/90 mmHg) were examined using multivariate analysis adjusted for possible confounding factors.

RESULTS

Adjusted IMT in individuals with sustained hypertension [0.77 mm; 95% confidence interval (CI) 0.75 to 0.79 mm] and MHT (0.77 mm; 95% CI 0.73 to 0.80 mm) was significantly greater than in those with sustained normal blood pressure (0.71 mm; 95% CI 0.69 to 0.72 mm) and WCHT (0.72 mm; 95% CI 0.71 to 0.74 mm) (P < 0.0001). The odds ratios for the presence of plaques in all four groups were similar to the trends in IMT.

CONCLUSIONS

Our findings imply that CBP measurements alone are insufficient to distinguish individuals at high risk of carotid atherosclerosis from those at low risk. However, these individuals do have distinct HBP measurements, suggesting that HBP measurement could become a valuable tool for predicting carotid atherosclerosis.

The Risk of Cardiovascular Events in Japanese Hypertensive Patients with Hypercholesterolemia: Sub-Analysis of the Japan Lipid Intervention Trial (J-LIT) Study, a Large-Scale Observational Cohort Study

Coronary events and stroke are leading causes of death in Japan. However, the effects of hypertension on the risk of coronary events and stroke have not been well established in Japanese hypercholesterolemic patients. This study aimed to determine the relationship between the risk of coronary events or stroke and blood pressure and cholesterol levels during low-dose simvastatin treatment using data from the Japan Lipid Intervention Trial (J-LIT) study (a large scale nationwide cohort study). In the present study, 47,294 hypercholesterolemic patients were treated with open-labeled simvastatin (5 to 10 mg/day) for 6 years by a large number of physicians in a clinical setting. The adjusted incidence rates of coronary events in males and females were 8.9 and 2.3 and those of stroke were 17.6 and 11.3/1000 patients during the 6-year period, respectively. The incidence rate of stroke was higher than that of coronary events in both males and females. An obvious sex difference was observed in terms of the incidence of coronary events. The risk of coronary events, stroke, and total cardiovascular events were increased, with elevations in blood pressure observed in patients treated for hypercholesterolemia. The risk of total cardiovascular events in the groups exhibiting less lipid control increased, with lower blood pressure levels than those of the well-controlled group. For patients with hypercholesterolemia and hypertension, blood pressure should be strictly controlled in order to prevent both coronary events and stroke, and the serum total cholesterol levels should be maintained at low levels as well.

Complications in adults with growth hormone deficiency--a survey study in Japan

It has been reported that adult patients with growth hormone deficiency (GHD) have increased risk factors for cardiovascular disorders in Western countries. However, data on this issue in Japan have not been fully investigated. To clarify the situation on this issue in Japan, a nationwide questionnaire survey was conducted by Study Group of Hypothalamo-Pituitary Disease, and medical records of 863 adult patients were recruited. The incidences of complications and risk factors for cardiovascular diseases were compared between GH deficient patients (GHD, n = 494) and GH intact patients (GHI, n = 369). The incidence of myocardial infarction was higher in GHD (1.2%) than in GHI (0.8%), but not significantly. The incidences of angina pectoris and liver dysfunction were significantly higher in GHD than in GHI (2.8 vs 0.8%, p = 0.048, and 11.9 vs 5.5%, p<0.0001, respectively). The prevalences of obesity and hyperlipidemia (HL) were significantly higher in GHD (p = 0.004, p<0.001, respectively). Combinations of HL plus diabetes mellitus (DM) or hypertension (HT) were more common in GHD than in GHI (HL + DM; 7.2 vs. 2.9%, HL + HT; 10.9 vs. 2.9%). These results indicated that GH deficiency have an increased prevalence of cardiovascular risk factors in Japanese similar to Western countries, and suggested that GH supplement therapy may be needed to reduce those complications.

Prognosis of hypercholesterolemic patients taking pravastatin for five years: the Chiba Lipid Intervention Program (CLIP) Study

The Chiba Lipid Intervention Program (CLIP) Study was designed to clarify the prognosis of Japanese hypercholesterolemic patients taking pravastatin for 5 years. Hypercholesterolemic patients (n = 2,529) with a total cholesterol level > or = 220 mg/dl and without histories of ischemic coronary heart disease and/or cerebral infarction were administered pravastatin (10-20 mg/day). Among them, 2,131 took pravastatin fully (Pravastatin-continued group), and 398 discontinued the treatment (Discontinued group). The baseline total cholesterol level was 264.3 +/- 34.7 mg/dl (mean +/- standard deviation). The mean reduction rates of total cholesterol and low-density lipoprotein (LDL) cholesterol were 18.0% and 27.2%, respectively. Mild and moderate adverse events occurred in 86 cases (3.6%). Serious adverse events were not observed. Death rates of the pravastatin-continued group and of the discontinued group were 2.6 and 16.0/1,000 persons/year, respectively. Cardiac events (fatal and nonfatal myocardial infarction, cardiac death, angina pectoris) in all, occurred in 35 patients (incidence rate = 2.77/1,000 persons/year). In the pravastatin continued group, 9 causes of fatal and nonfatal myocardial infarction occurred (0.84/1,000 persons/year), whereas in the discontinued group, 4 cases occurred (2.06/1,000 persons/ year). The risk ratio for cardiac events was correlated with the number of risks. In the low-risk group (< or = 1 risk), decreased rates of LDL-cholesterol were less in the cardiac event group than the non-cardiac event group (LDL-cholesterol; 16% vs 25%, p = 0.04). These results suggested the following; 1) Pravastatin maintained a cholesterol lowering effect long-term without serious complications. 2) Pravastatin administration might reduce the mortality rate and myocardial infarction. 3) The combination of multiple risks is a strong factor for a cardiac event in addition to hypercholesterolemia.