Nationwide survey on Kawasaki disease in Japan.

Results of the statistical analysis of a nationwide survey of patients with Kawasaki disease diagnosed within a 2-year 6-month period, from July 1982 to December 1984, are as follows. (1) The cumulative number of patients reported by the end of 1984 was 63,399 (36,891 boys and 26,508 girls; male to female ratio 1.4). (2) There were two epidemic years, 1979 and 1982, in which the numbers of patients were more than twofold that of the previous years. (3) A curve plotted for age-specific incidence rate showed a unimodal peak at age 1 year. (4) Steroid therapy was used for 6.3% of the patients, aspirin for 89.8%, antibiotics for 57.6%, and gamma-globulin for 11.4%. (5) The proportion of sibling cases was 1.4% and that of recurrent cases was 3.9% of all cases reported. (6) The incidence of cardiac sequelae in 1 month after disease onset was 17.2%.

Recent results of health examinations on the general population in cadmium-polluted and control areas in Japan.

Health examinations by a revised method aimed at detecting renal tubular dysfunctions more effectively were conducted on the general population aged 50 years and over in cadmium-polluted areas (1826 persons) and control areas (1611 persons) in four prefectures in Japan in 1976. Although detailed analysis of the data is not yet completed, some of the results obtained are described here. The prevalence of glucosuria and low molecular weight proteinuria, frequency of decreased % TRP, and cadmium concentrations in urine are higher in the cadmium-polluted areas than in the controls. Clinically diagnosed cases with tubular dysfunctions seem to follow the same trend as above, though these cases are very few in number and they are limited to the advanced age group. When cadmium concentration in rice is taken as an index, a dose-response relationship is not necessarity explicit in the observations by prefecture. However, suggestive data are obtained in the observation by district in one cadmium-polluted area.

Childhood thyroid diseases around Chernobyl evaluated by ultrasound examination and fine needle aspiration cytology.

Screening by ultrasound examination and fine-needle aspiration cytological biopsy (FNA) was conducted in five regions in Belarus, Ukraine, and Russia to investigate the prevalence of childhood thyroid diseases around Chernobyl. Gomel, Zhitomir, Kiev, and the western area of Bryansk are the administrative regions where severe radioactive contamination occurred. The subjects from Mogilev, where contamination was relatively low, served as controls. Among 55,054 subjects (26,406 boys and 28,648 girls), the prevalence of ultrasonographic thyroid abnormalities such as nodule, cyst, and abnormal echogenity was significantly higher in the regions with severe contamination than in Mogilev. Of the 1,396 children showing echographic thyroid abnormalities 197 were selected for FNA, and a sample was successfully obtained for diagnosis from 171 (51 boys and 120 girls) of the 197 subjects. The aspirate was insufficient for diagnosis in the remaining 26 subjects. Thyroid cancer was encountered in four children (2.3%) from the contaminated regions, two children being from Gomel. The other thyroid diseases were follicular neoplasm, 6.4%; adenomatous goiter, 18.7%; chronic thyroiditis, 31.0%; and cyst, 24.0%, suggesting that a major cause of thyroid nodularity is nonneoplastic changes, mainly chronic thyroiditis and cysts. These results will serve as an important data base for further analyses and suggest that childhood thyroid diseases, including both neoplasms and immunological disorders, are consequences of radioactive fallout.

Geographical distribution of cerebrovascular disease mortality and food intakes in Japan.

The present study focuses on an analysis of the relationship between cerebrovascular disease mortality and food intake. For this purpose, standardized mortality ratios(SMRs) from cerebrovascular disease were calculated for 3341 basic administrative units (wards, cities, towns and villages) between 1969 and 1978 in Japan. The major nutrient intakes and 30 selected food items were obtained from the 1974-1974 Ministry of Health and Welfare, National Nutrition Surveys in 1040 randomly sampled census tracts in 600 areas (18% of the nation). Our analysis demonstrates that the geographical pattern of cerebrovascular disease SMRs in Japan vary from higher in East Japan to lower in the West, and higher in the less urbanized areas, and lower in the more urban ones. Foods positively associated with cerebrovascular disease were rice and other starchy foods, pork, algae (seaweed), and salty foods such as miso (soybean paste), pickled vegetables, soy sauce and salted fish. All of these foods, with the exception of pork, are part of the traditional Japanese diet. On the contrary, mortality was negatively associated with intakes of wheat, butter and margarine, beef and eggs, items considered to be representative of a European diet. Using a stepwise multiple regression analysis, miso and salted fish were selected as positive, and beef and eggs as negative correlates of cerebrovascular disease mortality. According to these results, it is suggested that these four foods are useful as negative and positive indicators of improvement in dietary intakes as related to the reduction in the occurrence of cerebrovascular disease.

The epidemiological approach to cadmium pollution in Japan.

The study of health problems due to cadmium pollution in Japan originated from an endemic episode of Itai-itai disease in a rural area in north-central Japan after World War II. The disease was defined as osteomalacia with tubular changes in the kidney and considered to be associated with excess intake of cadmium. This episode motivated the Japanese Government to conduct health examinations on the general population in cadmium-polluted and non-polluted areas throughout the country since 1969. Although Itai-itai disease-like bone changes were rarely found, these studies revealed a higher prevalence of renal tubular dysfunction among elderly people in the cadmium-polluted areas. No significant difference was noted in cancer mortality, but mortality from cardiovascular diseases and all causes tended to be lower in cadmium-polluted areas. Clinical and pathological studies in man as well as experiments on primates have recently been made to elucidate the pathogenesis of Itai-itai disease and the health effects of cadmium. The lack of knowledge on the ecological and biological complex of cadmium resulted in the impediment of studies on this problem. The lesson from this experience is that basic research is essential for promoting the study of pollutants such as heavy metals, though pollution problems usually require urgent solutions.

[Health effects of atomic bomb radiation].

The health effects of atomic bomb radiation have been studied by the Atomic Bomb Casualty Commission (ABCC) and its successor, the Radiation Effects Research Foundation (RERF) based on a fixed population of atomic bomb survivors in Hiroshima and Nagasaki which had been established in 1950. The results obtained to the present can be classified into the following three categories: (1) The effects for which a strong association with atomic bomb radiation has been found include malignant neoplasms, cataracts, chromosomal aberrations, small head size and mental retardation among the in utero exposed. (2) A weak association has been found in the several sites of cancers, some non-cancer mortalities and immunological abnormalities. (3) No association has been observed in some types of leukemia, osteosarcoma, accelerated aging, sterility and hereditary effects.

Indoor infection in a modern building.

Outbreaks of tuberculosis (TB), which are of a type rarely experienced in the past, have recently increased in Japan. An example of such an outbreak, which occurred in a modern building with fixed sash windows, will be described. The occurrence of four TB cases, which had been found during the period between May 1979 and June 1980 among company employees working in the same building in downtown Tokyo, motivated the conduct of epidemiological and environmental surveys on this episode. The first case, a 36-year-old male with a positive smear and cavities in both lungs, was considered to have been in an infectious state for about one year before his admission to a TB hospital in June 1979. Follow-up investigation of 99 contacts until March 1982 revealed the occurrence of 16 secondary cases. The secondary attack rate was highest among those working on the same floor of the building as this first case, but no case was found among employees of another company that occupied this building. The desks of secondary cases were aggregated near and around that of the first case. Although this building had central air-conditioning, ventilation was often closed for energy conservation purposes. This resulted in the increase of carbon dioxide concentration in the air up to a level of more than 1,000 ppm during working hours and to as high as 2,000 ppm when the ventilation was closed. It was thus concluded that the indoor infection of TB in this episode was attributable to the insufficient ventilation in the building.