Incidence and mortality of malignant tumors among medical diagnostic X-ray workers in China

The incidence and mortality of malignant tumors in medical workers of diagnostic X-ray departments from 1950 to 1980 were investigated in 24 provinces of China. The control group was composed of medical staff from non-X-ray departments in the same hospitals. The number of persons surveyed in the irradiated group was 26983 (accumulated 301694 person-years) and that in the control group was 25785 (accumulated 401781 person-years). During this period, the incidences of all malignant tumors were 75.24 . 10-5 in the irradiated group and 58.74 . 10-5 in the control group, and the mortality rates were 50.30 . 10-5 and 36.78 . 10-5, respectively. The incidences of leukemia were 9.61 . 10-5 in the irradiated group and 2.74 . 10-5 in the control group, the standardized incidence of leukemia being 9.67 . 10-5 in the irradiated, which was significantly higher than that (2.77 . 10-5) in the control (P<0.01). The mortality rates of leukemia were 8.60 . 10-5 in the irradiated group and 1.24 . 10-5 in the control group, the standardized mortality rate of leukemia being 8.60 . 10-5 and 1.28 . 10-5, respectively. Both kinds of mortalities were significantly different between two groups (P<0.01). (Author)