The corrected death rate is by far higher among those engaged in agriculture and fishery than those engaged in other occupations.
The purpose of this study is to provide data useful for the public health service and medical care in the future. For this purpose, investigation was made into the ways of life the deceased had led while alive and medical treatment they had received. Furthermore, the causes of death were examined in light of social as well as medical factors.
1. Our survey at hospitals showed that the largest number of deaths was caused by malignant neoplasm. This was followed by cerebrovascular disorder, heart disease and others, in that order.
According to a comparative study conducted by a group of researchers at Hiroshima General Hospital on the causes of death between urban and rural communities, the ratios of cerebrovascular disease, accidents, trauma and suicide to the total are higher in rural areas than in urban areas, respectively. Malignant neoplasm and myocardial infarction were associated with urban lifestyle. As for neoplasm, lung cancer more frequently attacks urbanites, while cancer of the colon occurs in rural inhabitants.
2. Pattern of Death
A close look at death notices does not always reveal a clearcut pattern of death in rural areas. It varies greatly depending on economic, industrial and other factors of regions.
However, a general picture of what takes the lives of people can be drawn. The most frequent causes of death among those at 50 or below are accidents, neoplasm, and suicide.
A study of the suicide cases in Shimane Prefecture over the past eight years shows that there is a upward tendency for men aged 65 years or above in urban areas and younger than 65 in rural areas to commit suicide. As for women, suicide cases are on the rise among those younger than 65 years old in both urban and rural areas. As the causes of self-killing, suffering from illness stands out from any other, with mental disturbance, household economy, family trouble, pressure of work and love affairs trailing behind.
3. Start of Medical Examination
Of the dead, the majority had visited hospitals or clinics before their death, complaining about displeasure. About 30% of those who had suffered from mental disease, attempted suicide or had some other reasons had seen doctors. Unexpectedly, however only a small number of them consulted physicians after undergoing a regular mass health screening.
Within a month from the onset of subjective symptoms, 80% received medical examination and most of them visited hospitals or clinics early in the morning. Nevertheless, many met their death in a relatively short period of time. That was a surprising finding.
To be more specific. In one month after the onset of their disease, 30% of them died; in 6 months, about 60%; and one year, 70%. In the cases of neoplasm, about 50% survived for more than one year. A very few, who had their malady detected early in a screening, remained alive for more than five years. This fact proved that the screening for early detection of diseases is important.
4. Risk Factors The correlations between the major causes of death and the ways of living were examined to ponder over risk factors for diseases. However, it was difficult to link the causes of death and lifestyles. Various research institutes study this subject in different ways. The biological process from birth to death is interlocked with various social factors and environmental influences.
Based on the findings of a case control study on lung cancer, we obtained the odds ratios by occupation. The ratio was low among those engaged in agriculture, forestry and fishery, and significantly high among those working in wood and metal processing plants. Moreover, it was made clear that cigarette smoking and exposure to mineral particulates multiply risks of developing lung cancer.

The present author found five patients with attack of allergic diseases caused by working in the tea-garden. To determine causative allergen, an intracutaneous reaction test, provocation test, Prausnitz-Kustner reaction test were carried out on these cases. As a result, these cases were considered to be caused by the inhalation of tea-leaf ciliae scattered in the air, and reasoned that other ciliae of leaves could be inhalative allergens.
Soon after this study had done, the author found many respiratory symptoms among cultivator of chrysathemum. By some allergological tests, these symptoms were also considered to be caused by the inhalation of chrysanthemum-leaf ciliae.
In this article, the author reviewed on these inhalative allergy of ciliae of leaves and respiratory impairments due to agricultural work.

Professional termite-control crews handle a large amount of organophosphorus insecticides such as chlorpyrifos and dichlofention (ECP), and inevitably are exposed to these insecticides throughout the spraying season. To assess the effects of exposure to organophosphates on the immune system of the insecticide applicators, subpopulation and functional subsets of lymphocytes in the blood were investigated.
Between the termite exterminators and the control group, significant differences were found in the mean levels of helper CD4+CD45RO+ cells, suppressor CD8⁺CD28^- cells and precytotoxic CD8⁺CD28⁺ cells. The termite exterminators showed lower percentages of bot CD4⁺CD45RO⁺ cells and CD8⁺CD28⁺ cells, and a higher percentage of CD8⁺CD28^- cells. In addition, a significant difference was observed in the percentages of CD20⁺ cells, which are regard as pan B cells, and both CD28⁺ cells and CD45RO⁺ cells associated with antigens of activated T cells. In the termite exterminators, the percentages of both CD28⁺ cells and CD45 RO⁺ cells decreased and the percentage of CD20⁺ cells increased.
These findings suggest that the alterations on subpopulation and functional subsets of lymphocytes in termite exterminators could be associated with the effects of chronic exposure to high doses of organophosphates on the immune system.

Studying the causes of death among inhabitants in mountain villages located alongside the middle stream of the Tenryu River, and farming-fishing villages located along Tokyo Bay, we found that the death rate from lung cancer was high in the former, and that from stomach cancer was high in the latter. So, in those two districts, we carried out case-control studies about both kinds of cancer. Investigation was made into the dead cases from lung cancer, 84 male cases and 168 male controls, and the dead cases from stomach cancer, 83 male and 39 female cases and the same number of controls. We selected these controls, matching district, sex, age, and year of death, and studied occupation and smoking in lung cancer cases ; occupation, eating habits, kinds of food, drinking and smoking in stomach cancer cases. The odds ratio concerning to lung cancer was as low as 0.40 among people engaged in agriculture, forestry or fishery. But that was as high as 3.25 among people exposed to metal dust, and also as high as 3.10 among those exposed to wood dust. The multiplier effect could be suggested between smoking and metal or wood dust exposure. The odds ratio concerning to stomach cancer was as low as 0.69 among males engaged in agriculture, forestry or fishery. Regarding eating habits, ‘rapid eating’ was as high as 2.57 in males, 3.00 in females. Concerning the kinds of food, ‘salted fish’ was as high as 1.90 in males, and ‘white vegetables’ was as low as 0.36 in females. No assocciation was found between stomach cancer and smoking or drinking.

It is to be noted that in rural districts where they live and work in fresh and clean air the incidence of chronic obstructive pulmonary diseases is as high as in the districts of air-pollution. Besides, there are a variety of respiratory diseases particularly incidental to life-environment and farm work. To be more informed of their actual conditions, the Japanese Association of Rural Medicine organized a special study group and has carried out various studies for four consecutive years with grants from the Ministry of Health and Welfare. The major results obtained are as follows:
(1) There were a variety of farm operations which produced or increased respiratory symptoms, including thrashing and scatteringof agricultural chemicals;
(2) It became clear that there existed in an advanced age group certain cases of “agricultural pneumoconiosis” which could be regarded as the terminal of the so-called “thrash-bronchitis”
(3) Among the cultivators of rush, raw material for Tatami, there existed cases of pneumoconiosis;
(4) There were a variety of agents to produce bronchial asthma, such as rice straw, chaff, tea-leaves and chrysanthemum-leaves;
(5) In Japan only two cases of farmer's lung were reported prior to this study. One more case was added to the list by this study group. Besides, cases positive to fungous agents were found among farmers in considerably high percentage.

It is to be noted that in rural districts where they live and work in fresh and clean air the incidence of chronic obstructive pulmonary diseases is as high as in the districts of air-pollution. Besides, there are a variety of respiratory diseases particularly incidental to life-environment and farm work. To be more informed of their actual conditions, the Japanese Association of Rural Medicine organized a special study group and has carried out various studies for four consecutive years with grants from the Ministry of Health and Welfare. The major results obtained are as follows
(1) There were a variety of farm operations which produced or increased respiratory symptoms, including thrashing and scattering of agricultural chemicals;
(2) It became clear that there existed in an advanced age group certain cases of “agricultural pneumoconiosis” which could be regarded as the terminal of the so-called “thrash-bronchitis”
(3) Among the cultivators of rush, raw material for Tatami, There existed cases of pneumoconiosis;
(4) There were a variety of agents to produce bronchial asthma, such as rice straw, chaff, tea-leaves and chrysanthemum-leaves;
(5) In Japan only two cases of farmer's lung were reported prior to this study. One more case was added to the list by this study group. Besides, cases positive to fungous agents were found among farmers in considerably high percentage.

One is inclined to imagine that the incidence of respiratory diseases will be negligible among rural people who live and work in fresh and clean air. On the contrary, however, we have reports on the high incidence of chronic obstructive pulmonary diseases and on the existence of a variety of specific respiratory diseases which are incidental to farm work. To clarify this situation, the Japanese Association of Rural Medicine organized a special study group and carried out various studies with grants from the Ministry of Health and Welfare. This is the study group's summary report of the four year research project prepared in conclusion of the project.
The actual state of respiratory diseases among rural people, as investigated by the present study group, can be summarized as follows:
1) In rural districts, in spite of its freedom air-pollution, there exist in high percentages people suffering from respiratory symptoms and patients of obstructive pulmonary diseases. As the important cause of this phenomenon, farm operations, especially thrashing, rice-hulling, compost preparation, scattering of agricultural chemicals can bementioned, which invite the development of symptoms and their aggravation.
2) Pathologically, farmer's pneumoconiosis attributable to farm operation dust was evidenced, crying for the necessity of dust prevention measure during farm operations.
3) In connection with atopic asthma the study group proved the antigenicity of rice-straw, wheat-straw, celiae of tea-sprout, young leaves, and chrysanthemum leaves. There are also anumber of already known antigens. It is necessary to establish measures for its prevention and treatment.
4) In rural districts of Japan, esp. in stock-raising farm houses, there are in comparatively high percentages those who react positive to fungous antigens which are the causes of farmer's lung. However, there have hitherto been reported only two cases, and the study group added one more. In the future, more extensive practice of immunological tests and clinical follow-ups of the positive cases will be necessary.
5) In view of the results reported above, it is considered that there are numerous questions concerning respiratory troubles and diseases in rural districts which are awaiting further study.