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Original article
Risk of asthma and chronic obstructive pulmonary disease in a large historical cohort of Danish firefighters
  1. Julie Elbæk Pedersen1,
  2. Kajsa Ugelvig Petersen1,
  3. Niels Erik Ebbehøj2,
  4. Jens Peter Bonde2,
  5. Johnni Hansen1
  1. 1 The Danish Cancer Society Research Center, The Danish Cancer Society, Copenhagen, Denmark
  2. 2 Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
  1. Correspondence to Julie Elbæk Pedersen, The Danish Cancer Society Research Center, Copenhagen 2100, Denmark; juliep{at}


Objective Firefighters are exposed to numerous respiratory hazards, but large studies on the risk of pulmonary disease are scarce. The objective of this study was to examine incidence of asthma and chronic obstructive pulmonary disease (COPD) in a nationwide cohort of Danish firefighters.

Methods We used individual historical employment records on 11 968 Danish male firefighters primarily supplied by trade unions and fire agencies. Furthermore, we used the Supplementary Pension Fund Register to form an occupational reference group consisting of military employees. Information on respiratory incidence was retrieved from the nationwide Danish National Patient Registry. Age and calendar time standardised incidence ratio (SIR) and Poisson regression analyses (incidence rate ratio) were used for estimation of risks, including 95% CIs.

Results Compared with military employees, the overall age and calendar-time adjusted risk for asthma was significantly increased among full-time firefighters (SIR=1.58, 95% CI 1.32 to 1.88), but not among part-time/volunteer firefighters. Full-time firefighters’ risk for asthma did not vary by duration of employment. No consistent evidence of an increased risk for chronic obstructive pulmonary disease was detected.

Conclusion Danish firefighters have an increased risk of asthma, but the causes, whether occupational or not, remain to be established.

  • firefighting
  • asthma
  • COPD
  • occupational epidemiology
  • historical cohort study

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  • Contributors JEP: performed programming of data, analyses, participated in interpretation of results and wrote the manuscript. KUP: was responsible for collecting the data, performed programming of data, participated in the interpretation of results and revised the manuscript critically. NEE and JPB: engaged in the design of the study, participated in the interpretation of results and revised the manuscript critically. JH: was a key contributor in the design process of the study and supervised the data collection, programming, analyses and participated in the interpretation of results, and supervised the writing of the manuscript; the overall content of the manuscript was guaranteed him. All authors have read and approved the final manuscript.

  • Funding Funding was provided by The Danish Working Environment Research Fund.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.