Objective Firefighters are exposed to numerous occupational hazards including chemicals, particles, shift work and physical strain potentially affecting their health. Recently, firefighting has been classified by the International Agency for Research on Cancer as possibly carcinogenic due to a reported increase in non-Hodgkin’s lymphoma, testicular and prostate cancer, based, however, on relatively small studies focusing mainly on mortality rather than incidence. The aim of this study is to examine whether Danish firefighters have increased incidence of specific cancers.

Method We have established a historical cohort of Danish firefighters by collecting individual employment and membership records from employers and trade unions. Reference groups, i.e. the general working male population, police and military, are established using information from the Supplementary Pension Fund Register, which has kept detailed information on all employments in Denmark since 1964. Information on specific cancers is assigned to all members of the cohort and reference groups by register linkage using the unique Central Person Number assigned to all residents in Denmark and information from the Danish Cancer Registry and the Danish Civil Register. Further, we have established job-exposure matrices based on records from historical archives, including analyses of fire smoke since 1930. In addition, duration of employment as firefighter, first year in service and job function are used as proxies for exposure levels. Standardised incidence ratios for the selected cancers will be estimated.

Results We have identified a total of 16.860 Danish firefighters, born in the period 1878-1997 and in service from 1901 to the end of follow-up in 2014.

Conclusion We have identified a large group of Danish firefighters covering exposure scenarios for more than 100 years of firefighting. We will present results on incidence of selected cancers for this occupation.