粉じん作業離職後のじん肺

Abstract

In Japan, there were about 12, 000 workers awarded compensations for total disability due to pneumoconiosis in December 1977. The number of new cases showed to be on the increase year by year, especially from the year 1971 onward. The purpose of this study was to interpret more accurately characteristics and factors of the incidence of pneumoconiosis. Questionnaires were mailed to 3, 400 cases awarded compensations for total disability due to pneumoconiosis out of which 2, 991 were completed and returned. The results were as follows: 1) Of the 2, 991 cases, 47% were certified at some time after having left dusty occupations. Perecentage of the cases by succeeding periods of year certified showed to increase, 17% from September 1955 to March 1960, 52% from April 1960 to March 1978 and 69% from April 1978 to June 1979. 2) The length of the period from the separation from dusty occupations to the certification for compensation showed to increase. Percentage of the cases certified after ten years and over from the separation was 2% from September 1955 to March 1960, 21% from April 1960 to March 1978 and 33% from April 1978 to June 1979. 3) Mean age of the cases certified after having left dusty occupations was higher than that of the cases certified within the period employment of the dusty occupations. 4) Of 1, 402 cases certified after having left dusty occupations, 49% were coal workers, 28% metal miners and 10% tunnel workers and those in construction. 5) Mean age of the coal workers certified was the highest among those 1, 402 certified cases. Regarding the reasons of separation of coal workers who were certified after having left, discharge was 40%, age-limit 28%, aggravation of physical conditions 19% and other 13%. 6) Mean age of the tunnel workers and those in construction who were certified was the lowest and the mean duration of the service was the shortest among those 1, 402 certified cases. Regarding the reasons of separation of these workers, aggravation of physical condition was 57%, discharge 14%, age-limit 0%, transference 16% and others 13%.