The cancer risk and epidemiological analysis for medical X-ray workers in Shanghai / 中华放射医学与防护杂志

ABSTRACT

Objective:To study the risk of malignant tumor in medical X-ray workers in Shanghai and provide scientific data for the study on occupationally exposed population.Methods:A retrospective cohort study was conducted to investigate the risk of cancer. Totally, 715 physicians in radiology departments during 1950-1980 in Shanghai were selected as exposure group, while 738 with non-radiology departments in the same hospital in the same time period as control group. The basic information on the selected physicians and associated cancer incidence were collected. The comulative number of individuals with cancer from 1980 to 2021 was calculated. The relative risk ( RR) of cancer was analyzed using logistic regression model in terms of gender, birth year, and work starting year. As well, stratified analysis based on confounding factors was conducted. Results:A total of 1 369 individuals were followed up, including 668 in exposure group and 701 in control group. The cumulative person-year of observed individuals was 52 980. As of 31 December 2021, a total of 199 patients with various malignant tumors were identified. The results of the logistic regression analysis showed that the risk of malignant tumors in exposure group was significantly higher than that in control group. The adjusted RR of solid cancer and total cancer was 1.49 (95% CI 1.08-2.05, P=0.015) and 1.40 (95% CI 1.02-1.92, P=0.036), respectively. In addition, the risk of thyroid cancer in exposure group was significantly higher than that in control group ( RR=10.06, 95% CI 2.05-49.62, P=0.005). Stratified analysis showed that the exposure group had a higher risk of total cancer both for femals and workers taking their jobs at age of 21-25. Conclusions:The risk of thyroid cancer, solid cancer and total cancer in the medical X-ray workers was significantly higher than that in control group. It is suggested that radiation protection in medical practice should be strengthened for the occupationally exposed workers, especially for femals and workers taking their jobs at low age.