Objectives To update the mortality experience of a previously studied cohort of 29 992 US urban career firefighters compared with the US general population and examine exposure-response relationships within the cohort.
Methods Vital status was updated through 2016 adding 7 years of follow-up. Cohort mortality compared with the US population was evaluated via life table analyses. Full risk-sets, matched on attained age, race, birthdate and fire department were created and analysed using the Cox proportional hazards regression to examine exposure-response associations between select mortality outcomes and exposure surrogates (exposed-days, fire-runs and fire-hours). Models were adjusted for a potential bias from healthy worker survivor effects by including a categorical variable for employment duration.
Results Compared with the US population, mortality from all cancers, mesothelioma, non-Hodgkin's lymphoma (NHL) and cancers of the oesophagus, intestine, rectum, lung and kidney were modestly elevated. Positive exposure-response relationships were observed for deaths from lung cancer, leukaemia and chronic obstructive pulmonary disease (COPD).
Conclusions This update confirms previous findings of excess mortality from all cancers and several site-specific cancers as well as positive exposure-response relations for lung cancer and leukaemia. New findings include excess NHL mortality compared with the general population and a positive exposure-response relationship for COPD. However, there was no evidence of an association between any quantitative exposure measure and NHL.
- longitudinal studies
- mortality studies
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Contributors LP participated in the collection of the follow-up data and wrote the first draft of the manuscript. SJB and JY conducted the analysis. All authors participated in the interpretation and presentation of results and have approved the final manuscript.
Funding The study was funded, in part, by an interagency agreement with the United States Fire Administration. The research was also supported, in part, by the intramural research programs at the National Cancer Institute and the National Institute for Occupational Safety and Health.
Disclaimer The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study received approvals from the Institutional Review Boards of the National Institute for Occupational Safety and Health and the National Cancer Institute. Informed consent was waived for this records-based study.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The data are protected by a 308(d) assurance of confidentiality that stipulates the data can only be accessed through a National Center for Health Statistics (NCHS) Research Data Center (RDC). Data will be made available to an NCHS RDC upon approval of a reasonable proposal for the data.
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