Yutaka Hasuo

Seasonal variation in stroke incidence in Hisayama, Japan.

We investigated seasonal variation in the incidence of cerebral stroke among the general population aged greater than or equal to 40 years in November of 1961 in Hisayama, Japan. During the 24-year follow-up period, 311 cases of cerebrovascular diseases occurred. The date or month of onset was determined in 308 cases, of which 51 were classified as intracerebral hemorrhage, 223 as cerebral infarction, and 27 as subarachnoid hemorrhage. We observed a significant seasonality in the incidence of all stroke (p less than 0.01), of intracerebral hemorrhage (p less than 0.05), and of cerebral infarction (p less than 0.01), whereas subarachnoid hemorrhage had no significant seasonal pattern. Subjects less than 64 years of age showed a significant seasonal variation in the incidence of both intracerebral hemorrhage (p less than 0.05) and cerebral infarction (p less than 0.01). A significant seasonal pattern for the incidence of intracerebral hemorrhage was also noted among persons with hypertension (p less than 0.05) or a high serum cholesterol level (p less than 0.05), whereas such a pattern for cerebral infarction was documented among normotensive persons (p less than 0.05) and those with a low serum cholesterol level (p less than 0.01). In addition, the incidences of intracerebral hemorrhage and cerebral infarction were negatively correlated with mean ambient temperature (p less than 0.01 and p less than 0.05, respectively), and all stroke and intracerebral hemorrhage in men were significantly related to intradiurnal temperature change (p less than 0.05 and p less than 0.01, respectively). The significance of the seasonal occurrence of stroke is discussed in relation to relevant risk factors.

Prevalence of Type 2 (non-insulin-dependent) diabetes mellitus and impaired glucose tolerance in the Japanese general population: the Hisayama study

SummaryWe determined the population-based prevalence of diabetes mellitus in members of the Japanese community, Hisayama aged 40–79 years old by a 75-g oral glucose tolerance test. The basic population used to calculate diabetic prevalence was 1,077 men (72.8% of the whole population in the same age range) and 1,413 women (80.8%) including ten diabetic patients on insulin therapy. In addition, we compared the prevalence of history of diabetes which was acquired by interview or questionnaire, between participants and non-participants in the 75-g oral glucose tolerance test, but they were not statistically different. The age-adjusted prevalence of diabetes to world population was 12.7% for men and 8.4% for women, and that of impaired glucose tolerance was 19.6% for men and 18.4% for women. These figures were much higher than those previously reported from several Japanese communities. The results obtained from the present study could reveal true prevalence of diabetes among the Japanese population. In addition, the reasons for the increasing prevalence of diabetes among the recent Japanese population are also discussed.

Prevalence and etiology of dementia in a Japanese community.

Background and Purpose We sought to determine the type-specific prevalence of dementia and its risk factors in elderly persons from the Japanese community of Hisayama. Methods We studied the prevalence of dementia in 887 Hisayama residents (353 men and 534 women) aged 65 years or older (screening rate, 94.6%) using various items of clinical information, neurological examination, and dementia scales. We also studied brain morphology in 50 of 59 determined to have dementia by computed tomography or autopsy during the subsequent 54-month period. Factors relevant dementia were compared between 27 patients with vascular dementia and 789 control subjects without dementia in a retrospective fashion. Results The prevalence rate of dementia among Hisayama residents aged 65 or older was estimated at 6.7%, with a females to males ratio of 1:2. Among 50 cases of dementia in which brain morphology was examined, the frequency of vascular dementia was 56%; this rate was 2.2 times higher than that for senile dementia of the Alzheimer type. Aging, hypertension, electrocardiographic abnormalities, and high hematocrit were significantly (p<0.05) and independently associated with the occurrence of vascular dementia. Conclusions Prevalence of dementia among the Hisayama residents was relatively identical to that previously reported, but vascular dementia was more predominant Risk factors for vascular dementia were similar to those for lacunar infarcts. Control of hypertension may be a key to reducing dementia among the Japanese population.

Incidence and prognosis of subarachnoid hemorrhage in a Japanese rural community.

Twenty-six first episodes of subarachnoid hemorrhage occurred among 1,621 Hisayama residents aged greater than or equal to 40 years during the 22-year follow-up of a prospective study. Subarachnoid hemorrhage was confirmed by both clinical and autopsy findings. The average annual incidence (96.1/100,000 population) was 3-13 times higher than any previously reported and steeply increased with age in both sexes, being 2.3 times higher for women than for men after adjusting for age. Nine patients (35%) died less than or equal to 8 hours after the onset of subarachnoid hemorrhage. None was correctly diagnosed on the death certificates, and four of the nine (44%) were misdiagnosed as intracerebral hemorrhage. We found the survival rate of patients suffering subarachnoid hemorrhage to be much lower than previously reported because we detected a large number of sudden deaths due to subarachnoid hemorrhage through the high rate of autopsy in our cohort (81.4%).

Intracerebral hemorrhage in a Japanese community, Hisayama: incidence, changing pattern during long-term follow-up, and related factors.

The incidence of intracerebral hemorrhage over 13 years is compared between two Hisayama cohorts. Among men aged 40 years or older, the annual incidence declined significantly from 3.1/1,000 in the early cohort (1961-1970) to 1.2/1,000 in the recent cohort (1974-1983). Massive ganglionic hemorrhage decreased, while small or medium-sized intracerebral hemorrhage increased in the recent cohort on pathologic or computed tomographic examination. These trends could be due to the reduced prevalence of hypertension in the Hisayama population. The association of serum total cholesterol with intracerebral hemorrhage is discussed based on the results during a 22-year follow-up period.

Accuracy of diagnosis on death certificates for underlying causes of death in a long-term autopsy-based population study in Hisayama, Japan; with special reference to cardiovascular diseases.

Major categorical diagnosis by International Classification of Diseases and type-specific diagnosis for cardiovascular diseases in death certificates were compared to the diagnosis made at autopsy in 864 consecutive autopsy cases aged 20 or over, among the Japanese residents in Hisayama town. Cerebral stroke was correctly diagnosed in 84%, malignant neoplasms in 78% and cardiac disease in 66%. Cerebral stroke and cardiac disease tended to be overdiagnosed, while malignant neoplasms were underdiagnosed. The validation of certified diagnosis was less reliable in the aged population, and in type-specific diagnosis of cardiovascular diseases. Cerebral hemorrhage with false negative or false positive diagnoses was usually classified into type unspecified stroke or different categories of cerebral stroke, while those misdiagnosed as cases of cerebral infarction frequently had no significant lesions in the autopsied brain. Finally, the relationship between the validation of diagnosis on the death certificates and the secular trend in cardiovascular disease in the Japanese vital statistics was discussed.

Hematocrit as a risk factor of cerebral infarction: long-term prospective population survey in a Japanese rural community.

To elucidate the relation of hematocrit (Hct) to the incidence of cerebral infarction, a prospective follow-up study of 16 years (1965-81) was performed in a general population sample of 1220 Hisayama residents aged 44 and over, of both sexes. Most of the subjects who died during the follow-up period were autopsied, the rate being 89.0%. Hct decreased with advancing age in men, but not in women. The average value for Hct was significantly lower in women than in men. According to the mean value +/- 1 SD of Hct, the subjects were grouped into 3, in each sex as follows: low (less than 35%), normal (35-45%) and high (greater than or equal to 45%) for men, and, low (less than 30%), normal (30-40%) and high (greater than or equal to 40%) for women. During the follow-up period, cerebral infarction occurred in 117 patients. The cumulative incidence of cerebral infarction in the low Hct group for men was the lowest, even after adjustments for age and blood pressure. Conversely, the incidence in the low Hct group of women was significantly higher than that in the normal Hct group and was consistently increased with time during 2-5 years of the follow-up. After the 6th year or later, however, the incidence was gradually but significantly increased in the high Hct group, compared with the normal Hct group. Since Hct levels were related with other variables such as serum total cholesterol, serum total protein, Quetelet index and prevalence of hypertension in both sexes, heavy alcohol consumption in men, and glucose intolerance in women, such variables were taken into account using Coxs proportional hazards regression model.(ABSTRACT TRUNCATED AT 250 WORDS)

A Sensitive Thyroid Stimulating Hormone Assay for Screening of Thyroid Functional Disorder in Elderly Japanese

The use of a screening test for thyroid functional disorder by sensitive thyroid stimulating hormone assay in the elderly was investigated. The basal thyroid stimulating hormone levels predicted the response of thyroid stimulating hormone to thyrotropin releasing hormone; it was suppressed in 99 (99.0%) of 100 hyperthyroid patients. Therefore, not only primary hypothyroidism but also hyperthyroidism can be excluded when the serum thyroid stimulating hormone levels are normal.

The association of the insulin resistance syndrome with impaired glucose tolerance and NIDDM in the Japanese general population: the Hisayama study

SummaryTo elucidate the risk factors for initiating glucose intolerance, the relevant factors were explored in a cross-sectional survey conducted in a sample population aged 40–79 years old selected from a Japanese community, Hisayama, Japan in 1988. A 75-g oral glucose tolerance test was used to classify 1,073 men (72.5% of the entire population in the same age range) and 1,407 women (80.5%) into normal, impaired glucose tolerance and diabetes mellitus groups. In all age and sex groups with normal glucose tolerance, the sum of fasting and 2-h post-load insulin values varied widely and demonstrated significant positive correlations with triglycerides, body mass index, waist-hip ratio, systolic and diastolic blood pressure, while it negatively correlated to HDL cholesterol (p<0.05). Insulin resistance was presumed to develop in normal glucose tolerance subjects with hyperinsulinaemia. The sum of the insulin concentrations, triglycerides, body mass index, waist-hip ratio and blood pressure levels was significantly associated with impaired glucose tolerance in all age and sex groups after adjustment for age (p<0.05) and was also related to diabetes in either all or some age and sex groups, respectively (p<0.05). It was shown that glucose intolerance in the general population was associated with the factors related to insulin resistance. These cross-sectional data, therefore, support the hypothesis that insulin resistance is the primary defect in the development of glucose intolerance in the Japanese general population. However, a further prospective study is still needed in order to confirm this hypothesis.

Prevalence and long-term prognosis of mild hypertensives and hypertensives in a Japanese community, Hisayama

The prognosis and outcome for mild hypertensives (90 mmHg less than or equal to diastolic pressure less than or equal to 104 mmHg) and hypertensives (diastolic pressure greater than or equal to 105 mmHg) was prospectively studied in Hisayama, Japan, and compared between 1621 subjects aged 40 years or over, recruited in 1961, and 2053 subjects recruited in 1974. Each cohort was studied in a follow-up which lasted 10 years. The pharmacological treatment of hypertension proved effective among residents recruited in 1974: the survival rate had favorably improved, and the rates of mortality from cerebral stroke and morbidity from intracerebral stroke and morbidity from intracerebral hemorrhage declined significantly in mild hypertensives and hypertensives in the more recently recruited population. The management of mild hypertension was considered more likely to be effective in reducing stroke than in reducing coronary heart disease in the Japanese general population.