In this article, an attempt was made to epidemiologically study chronic obstructive diseases of the lung, particularly chronic bronchitis, in Yachiho, a rural village in Nagano Prefecture.
The findings reveal that the incidence of chronic bronchitis among inhabitants from 40 to 69 years of age stands at 9.8% for males and 5.7% for females.This incidence is lower than in air-polluted areas but higher than in the non-polluted areas in Japan.
The cause to this phenomenon is presumably attributable to the influences of threshing work in paddy fields.
The repeated recurrence of Dakkoku Kikanshien (bronchitis for which threshing is responsible) once in a year is associated to a great extent with incidence of chronic bronchitis or its deterioration. Another conceivable factor is the inadequacy of household facillities against the cold weather in this village.

A total village health control program has been instituted in Yachiho Village (pop. 5, 211, 1975National Census) since1959.
When the deaths caused by respiratory diseases in this village are compared between the first eight years under the health control program (1960-67) and the second eight years (1968-75), the deaths caused by lung tuberculosis decreased by67% and those by pneumonia and bronchitis dropped by52%. On the other hand, there have been no drops in the deaths caused by pulmonary emphysema and bronchial asthma, and their ratios are higher than the national averages.
The prevalence of bronchial asthma among inhabitants of Yachiho Village stands at0.9% among males and1.2% among females, and these percentages are practically the same as the national averages. On the other hand, the prevalence of chronic bronchitis is9.8% among males and5.7% among females, and these ratios are lower than in air-polluted urban areas but higher than in nonpolluted cities.
A wide variety of farm work-particularly, rice threshing and hulling-greatly infuences the incidence and course of chronic bronchitis. It is therefore important to implement measures for the prevention of chronic bronchitis and pulmonary emphysema.

Of all types of farm work in Japan, the threshing of rice, in which dust is generated in large quantities, produces the worst influence on the respiratory organ, and the author termed this symptom “thresher's bronchitis.” The repetition of thresher's bronchitis gives rise to chronic bronchitis. There have been the autposy cases of elderly farmers who suffered from pneumoconiosis, as he had been exposed to dustin over 30 years of threshing work. The symptom might well be called “thresher's pneumoconiosis.”

In the last 20 years since 1960, the population of Yachiho Village in Nagano Prefecture had decreased by 1, 089 (17.5%). In the same period, the share of people, 70 years old and over, had increased from 4.5% to 10.4 percent, suggesting that depopulation and aging are in progress. By type of farm management, farming families with sideline jobs share 87.4% of the population and there is a conspicuous increase in the number of farming families for which the non-agricultural income is greater than the agricultural income. Agricultural mechanization began to make rapid progress in or 1970: power cultivators are owned by all farming families and power sprayers and harvesters by about half of them.
Due to the increase in income from non-agricultural work and the development of merchandise distribution systems, the intake of animal food, which used to be significantly small in the rural communities, has increased. In the last 20 years, the intake has increased by 6.3 times for meat, 1.4 times for fish and 4.7 times for eggs.
A health care program for all residents of Yachiho Village has been instituted since 1954. The disease the prevalence of which was found to be highest in the past annual mass health screenings is hypertension. A check of the prevalence of stroke and myocardial infarction, which is an important parameter to assess effects from hypertension control, indicates that the prevalence of strokes was down 30.7% in 1971-82, the latter half of the control perind, from 1959-70, the former half. Howevre, there was a slight rise is the prevalence of myocardial infarction. The prevalence of strokes to myocardial infarction was 16: 1 in the former half and 9: 1 in the latter half, suggesting that prevalence of strokes was overwhelmingly high.
There has been an increase in the number of healthy old people under the village's comprehensive health care program. They work till they reach a considerably high age and their health condition is good.
Due to changes in the dietary pattern and a drop in the burdening of farm work, however, the obesity rate has increased among residents of Yachiho Village, and the cholesterol level, which used to be low, has risen. Particularly conspicuous are the rises in the numbers of obese persons and patients with cholesteremia among females in their 50s and 60s and among males in their 40s.
In order to further decrease the prevalence of strokes and prevent an increase in that of myocardial infarction, there is a need for an elaborate guidance and control program by vocation, sex and age.

Conducted in the Saku district (pop: 105, 000) of Nagano Prefecture, a WHO collaborative study and a district survey on the onset of stroke (994 respondents), it is evident that the past history of hypertension was extremely significant both for patients with cerebral hemorrhage and cerebral thrombosis. Among patients with cerebral hemorrhage and those, 69 years old and under, with cerebral thrombosis, the group which undid or suspended hypertension treatment was evidently larger than that who continued to undergo treatment. But among those, 70 years old and over, with cerebral thrombosis, no significant statistical difference was noted between the two groups.
In Yachiho, a mountain village in the Saku district, hypertension control has been carried out since 1959. As a result of the adequate control of blood pressure, strokes as a whole have dropped by about 30% and cerebral hemorrhage has halved. But there are signs of an increase in the prevalence of cerebral infarction, and multiple cerebral infarction in particular, among the elderly.
In recent years, the Westernization of the dietary pattern has been in progress in rural communities, thereby raising the serum total cholesterol level among their residents. An epidemiological study of strokes in 1964-71 demonstrated minus correlations between serum total cholesterol and the incidence of cerebral thrombosis, but no such correlations are observed at present. Nor is any correlation observed between serum total cholesterol and cerebral infarction.

Of the patients with cerebral stroke admitted to the Saku Central Hospital from April 1972 to October 1977, we surveyed 60 people, aged 49 and under.
1) By type of disease, cerebral hemorrhage accounted for 40%, cerebral infarction 30%, and subarachnoid hemorrhage 30%. The prevalence of cerebral hemorrhage and subarachnoideal hemorrhage in this age group was higher than those in all ages.
2) Even in this age bracket, there were many with histories of hypertension and long periods of affection. The onset was observed among many of those who had not undergone or had discontinued treatment.
3) Abnormal ECG findings were observed in 35%.
4) Patients with a cardio-thoracic ratio of 51% and over in chest X-ray findings accounted for 64% of all patients.
5) Abnomally high hematocrit, serum and total cholesterol values were noted for few cases.
6) In respect to the prognosis of life and sequela, patients with cerebral infarction in this age bracket were better than those of all ages, but no statistically significant difference was observed between patients with ceberal hemorrhage in this age bracket and those in all ages.

A survey has been under way on the incidence of cerebral apoplexy among the inhabitants (pop. 105, 185, National Census, 1970) of the Saku district of Nagano Prefecture since April 1972.
This survey, which constitutes a WHO cooperative study, has been under way with cooperation rendered by the local Medical Association, Association of Public Health Nurses in Saku District and Saku Public Health Center with the Saku Central Hospital acting as the survey center.
In the period of two years till March 1974, 585 persons were registered as having been seized with cerebral apoplexy. The annual incidence rate stood at 265 per 100, 000 population. Classified by types of cerebral apoplexy, cerebral hemorrhage accounted for 26%, cerebral thrombosis for 57%, cerebral embolism for 3%, subarachnoid hemorrhage for 9%, and other types for 5%.
By sexes, the incidence rate among males was 1.3 times higher than among females. By ages, the incidence was highest in the seventies.
When the prognosis of cerebral apoplexy is viewed in terms of deaths in the early period of less than three weeks after the onset, the mortality rate stood at 45%.
The hospitalization rate of patients seized with cerebral apoplexy was 55%. There was a significant difference in the mortality rate between inpatients (with 28%) and outpatients (65%).
The ratio of concurrence of autopsy and clinical diagnosis stood at 83% with Okinaka's criteria and 79% with Ikeda's CVD index.
The incidence of hypertension before the onset of cerebral apoplexy was extremely high among the patients seized with cerebral hemorrhage and cerebral infarction.With respect to the treatment of hypertension, the discontinuance of treatment and the failure to undergo it are high in percentage among the patients seized with cerebral hemorrhage. With reference to cerebral infarction patients of 70 years and older in age, there is little defference between the group who discontinued or failed to undergo treatment and the group who underwent it.
The recurrence of cerebral apoplexy stood at 11% for cerebral hemorrhage, 19% for cerebral infarction, and 11% for subarachnoid hemorrhage.

A total of 194 cases of liver cirrhosis, which had been treated in our hospital during the past 5 years, were calssified by the causes into the following four groups:(I) hepatitis B virus, (II) alcoholic, (III) special origins, and (IV) reasons unknown. They each accounted for 23.2%, 35.6%, 1.5% and 39.7%, of the total.
Their clinical features and prognosis were examined. To be noted is the finding that many patients in group IV had had blood transfusions. This suggests that non A non B hepatitis viruses might be involved in the occurrence of the liver disease. On the whole, the five-year survival rate was 45.6%. There was not any significant difference among the four groups. However, prognoses were poor in groups II, I and IV, in that order.
As regards the cause of death, rupture of esophageal varice and hepatic failure showed a gradual decline, but complications of hepatocellular carcinomas sharply increased. Especially, in group I, this mortality was as high as 31.1%.

A check of the health of residents in their twenties and thirties in Nagano Prefecture's rural communities indicates that the rate of hypertensives and the incidence of cholesterolemia were low in those age groups. There were signs that the prevalence of obesity is somewhat high among males but low among females. Virtually no incidence of anemia was observed among men but the incidence was fairly high among women. The number of persons with hepatic dysfunction was relatively large among men. In terms of the intake of nutrients, there were not a few men for whom the meals were imbalanced, and the intake of alcoholic beverages was high.
It is necessary that women should refrain from taking in confectionary and taken in fishmeat, meat, milk, egg, soybeans and other proteins. In Nagano Prefecture's rural communities, there remain signs that the intake of salt is high even in young generation, so that it is important to take measures for the prevention of hypertension.