Mortality and cancer incidence in a pooled cohort of US firefighters from San Francisco, Chicago and Philadelphia (1950-2009)

Occup Environ Med. 2014 Jun;71(6):388-97. doi: 10.1136/oemed-2013-101662. Epub 2013 Oct 14.

Abstract

Objectives: To examine mortality patterns and cancer incidence in a pooled cohort of 29 993 US career firefighters employed since 1950 and followed through 2009.

Methods: Mortality and cancer incidence were evaluated by life table methods with the US population referent. Standardised mortality (SMR) and incidence (SIR) ratios were determined for 92 causes of death and 41 cancer incidence groupings. Analyses focused on 15 outcomes of a priori interest. Sensitivity analyses were conducted to examine the potential for significant bias.

Results: Person-years at risk totalled 858 938 and 403 152 for mortality and incidence analyses, respectively. All-cause mortality was at expectation (SMR=0.99, 95% CI 0.97 to 1.01, n=12 028). There was excess cancer mortality (SMR=1.14, 95% CI 1.10 to 1.18, n=3285) and incidence (SIR=1.09, 95% CI 1.06 to 1.12, n=4461) comprised mainly of digestive (SMR=1.26, 95% CI 1.18 to 1.34, n=928; SIR=1.17, 95% CI 1.10 to 1.25, n=930) and respiratory (SMR=1.10, 95% CI 1.04 to 1.17, n=1096; SIR=1.16, 95% CI 1.08 to 1.24, n=813) cancers. Consistent with previous reports, modest elevations were observed in several solid cancers; however, evidence of excess lymphatic or haematopoietic cancers was lacking. This study is the first to report excess malignant mesothelioma (SMR=2.00, 95% CI 1.03 to 3.49, n=12; SIR=2.29, 95% CI 1.60 to 3.19, n=35) among US firefighters. Results appeared robust under differing assumptions and analytic techniques.

Conclusions: Our results provide evidence of a relation between firefighting and cancer. The new finding of excess malignant mesothelioma is noteworthy, given that asbestos exposure is a known hazard of firefighting.

Keywords: Longitudinal studies < Methodology, speciality.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Asbestos / adverse effects
  • Cause of Death
  • Chicago / epidemiology
  • Cohort Studies
  • Digestive System Neoplasms / epidemiology
  • Digestive System Neoplasms / etiology*
  • Digestive System Neoplasms / mortality
  • Female
  • Firefighters*
  • Humans
  • Incidence
  • Lung Neoplasms / epidemiology
  • Lung Neoplasms / etiology*
  • Lung Neoplasms / mortality
  • Male
  • Mesothelioma / epidemiology
  • Mesothelioma / etiology*
  • Mesothelioma / mortality
  • Middle Aged
  • Neoplasms / epidemiology
  • Neoplasms / etiology
  • Occupational Diseases / epidemiology
  • Occupational Diseases / etiology*
  • Occupational Diseases / mortality
  • Occupational Exposure / adverse effects*
  • Philadelphia / epidemiology
  • Respiratory Tract Neoplasms / epidemiology
  • Respiratory Tract Neoplasms / etiology*
  • Respiratory Tract Neoplasms / mortality
  • San Francisco / epidemiology

Substances

  • Asbestos

Supplementary concepts

  • Mesothelioma, Malignant