risk comparison. The study we report here was designed to include a military reference cohort to provide a finer comparison. The SMR comparison to the U.S. male population of the period under study adds, as mentioned above, a perspective that is useful as long as one keeps its limitations in mind.
The results of our SMR analysis are presented in the following pages by service and disease category. In the case of the Navy for all-cause and allmalignancy mortality (Tables C-1 to C-2), the cohort is subdivided into the seven analysis levels as described in Chapter 10. For Navy leukemias, there were insufficient numbers of cases to use the seven-level analysis. For leukemias (Table C-3), the SMR data are collapsed over ranks and presented by participant status, boarder status, and Engineering & Hull status. For the Army (Table C-4, including the Air Corps) and the Marines (Table C-5), no occupational information is available; therefore, SMRs are calculated for the service as a whole. The disease categories include:
The tabulations of mortality rates (U.S. white male) we used as a comparison standard in this SMR analysis included chronic lymphocytic leukemia (CLL), which is not thought to be radiogenic. Of these there were approximately equal numbers in the controls and participants (10 and 11 respectively). Because of its nonradiogenic nature, CLL was excluded in the primary analysis using the proportional hazards model (see Chapters 10 and 11).