The Application of Cohort Analysis to the Study of Ionizing Radiation and Longevity in Physicians

Abstract

The mortality experience of 869 male physicians entering a radiology specialty society during the 50-year period 1905-1954 was compared with the experience of a similar group of 1170 entering a pathologist specialty group. The material was analyzed, keeping the data specific for age and for cohort of entry into the respective societies. There is a suggestion that for the cohorts entering the societies between 1905-1914 the mortality rates of radiologists above age 50 exceed those of the pathologists. The data for the entire 50-year cohort reveals no significant decrease in the survivorship of radiologists, compared to pathologists. Larger groups will be needed to obtain definitive findings, but even with the small numbers in this study it can be estimated that the maximum effect on median duration of life is likely to be no greater than from 3 to 4 years. Incomplete cause-of-death data, based on information from only 75% of the total deaths, showed an apparent excess of leukemia among the radiologists which was about equal in magnitude to an apparent tuberculosis excess among pathologists.