In Japan, hypertension and cerebrovascular diseases are reported to be more prevalent in rural than in urban areas, while the age-corrected prevalence of ischemic cardiac diseases is thought to be higher in urban areas. Not all rural areas show the same cardiovascular disease prevalence trend, however. In recent years in particular, the pace of urbanization of life-style has differed significantly from one region to another, a major factor contributing to regional differences in the cardiovascular morbidity pattern in rural areas. Another contributing factor is the fact that the aging of the population is progressing more rapidly in some areas than in others. As a whole, however, salt consumption is still greater is rural areas than in urban areas, although it has decreased significantly in recent years. Animal fat consumption is still smaller in rural than in urban areas. It is recommend-ed that cardiac disease prevention measures with special focus on problems specific to rural areas be taken, while maintaining good life-style in these areas. For example, there are a number of reports that serum cholesterol levels are similar in rural and urban areas in children, although they are lower in the former than in the latter in adults. When discussing cardiac diseases in rural areas from a long-term prospective, therefore, this fact must also be taken into account. Since the growing total number of elderly patients with cardiac diseases is expected to be much greater in rural areas than in urban areas, appropriate countermeasures, including the development of convenient diagnostic methods, care and rehabilitation methods, and creation of treatment facilities, are urgently required in rural areas. As mentioned above, each rural area has its own characteristics and problems. For this reason, it is desirable that appropriate measures be implemented taking into account the different characteristics of each region, backgrounds of disease and various risk factors. This paper therefore presents rural area-specific characteristics and problems related to major diseases.
Aspiration pneumonia is the fourth most frequeur cause of the death of Japanese. The disease accounts for 92% of the death of elderly people aged 65 and over. Pneumonia in the elderly is mostly due to silent aspiration. Aspiration is caused by disturbance of the pharyngeal reflex and cough reflex, which are profoundly reduced by the disturbances of brain activity. Mechanisms of both pharyngeal and cough reflexes are mediated by substance P. Strategy for increasing substance P should be further investigated. Mouth and teeth cleaning as well as sitting up straight for about four hours after meals significantly decreased febrile days related to respiratory infections. We also found that bactericidal clothes reduce infections in the elderly patients.
Stomach cancer is known as a neoplasm which shows big regional difference in the mortality, both internationally and in the country. This fact indicates an intimate relationship between the cancer generation and the lifestyle, especially dietary habits of the people. On the other hand, both Wynder and Doll showed that the biggest cause of all preventable cancers was foods. The present speaker showed the two-step theory of cancer generation of Berenblum, and applied the mechanism to his epidemiological study. In Japan, high-risk area of stomach cancer locates on the Japan Sea side of northern part, and the low-risk area locates on the Pacific Ocean side of this part. Dietary survey showed that the people of the high-risk area take shortage of vegetables, whereas those of low-risk area take plenty of vegetables. Also the mutagenicity of foods was high in the high risk area and low in the low risk area. The vegetables in diets tended to reduce mutagenicity of the diets. Two kinds of mutagen-depressive substances were purified and determined the chemical structure. On the other hand, sodium chloride was shown to be a promotor for the stomach cancer. It should be taking care from the stand-points of primary prevention of stomach cancer to take enough vegetables and reduce salty foods were stressed as the conclusion.
Tsutsugamushi disease (TD) had been recognized as a serious disease in Japan for more than several hundreds years, while, over the years the number of reported cases has been steadily declining with only a few cases being reported during the years of 1965 to 1975. The disease seemed to have been nearly eliminated: Since about 1976, however, the reported cases of the disease began to increase in many areas of the country even where the disease had never been identified previously. This significant increase in the number of reported cases of TD in Japan might be supported by the regulation of Chloramphenicol and the intensive use of β-lactum antibiotics which are not effective in treating TD but used as the first choice for most febrile infectious diseases. The use of the latter antibiotics led to the occurrence of several fatal cases, and these unfavorable occurrence have served as a stimulus to develop an enlightenment with rapid diagnosis and rapid treatment. Now, many prefectures have the authorized diagnostic laboratory using IP or IF technique. And the number of doctors who can identify the TD is much increasing, and resulted in the recent increase of the reported cases of TD in Japan. This will be rather valuable for the people who may suffer from this disease during the every incidental seasons. Because the patients will be easily cured by administration of the tetracycline group of antibiotics according to the correct diagnosis. Thus we believe that the early diagnosis and early treatment is most important and most effective way to control TD at present time in Japan.
Acute toxic effects from pesticides are fairly easily recognized, whereas the effects that result from long-term exposure to low doses are often difficult to distinguish. The chronic pesticide poisoning may occur theoretically, but as for the reported cases of pesticide poisoning and disorders the majority are generally acute pesticide poisoning and skin lesions. To make a proposal for the study of the chronic pesticide poisoning and disorders, the author have discussed about the subjects of general speech in the annual meeting of the Japanese Association of Rural Medicine and some nationwide reports on the chronic effects from pesticides. From the results, there are many controversial points to be improve as the confusion of the concepts and terminology used, overestimation of the decrease in serum and plasma cholinesterase activity for diagnosis of pesticide poisoning, fairly limited epidemiological study for evaluation of the chronic health effects associated with pesticide exposure, and so forth. Many detailed studies will be recommended as the following: 1) Establishment of the approaches to causal relationship between situation of pesticide exposure and health effects; 2) To seize the exposure levels of pesticides in the presentand the past; 3) The development of the methods of accurate examination and diagnosis, and their concrete application to a field study; 4) Establishment of the better designed of epidemiological study; 5) Enforcement of systematic study of health effects of occupational groups exposed to pesticides for long periods; 6) Establishment of the appropriate methods of toxicity testing and their well fitted extrapolation to health effects; 7) Opening to the general public of data on the toxicity testing and on the survey in an enterprise; 8) Cooperation and collaboration in studying among researchersand field workers, and others.