Cancer incidence and mortality among firefighters

Abstract

Firefighters are exposed to both known and suspected carcinogens. This study aims to systematically review the literature on the association of firefighting occupation and cancer incidence and mortality, overall and for specific cancer sites. A systematic review using PubMed, Embase, and Web of Science was performed up to January 1, 2018. We extracted risk estimates of cancers and calculated summary incidence risk estimates (SIRE), summary mortality risk estimates (SMRE), and their 95% confidence intervals (CI). Publication bias and risk of bias in individual studies were assessed using Begg's and Egger's tests and the Newcastle‐Ottawa scale (NOS), respectively. We included 50 papers in the review and 48 in the meta‐analysis. We found significantly elevated SIREs for cancer of the colon (1.14; CI 1.06 to 1.21), rectum (1.09; CI 1.00 to 1.20), prostate (1.15; CI 1.05 to 1.27), testis (1.34; CI 1.08 to 1.68), bladder (1.12; CI 1.04 to 1.21), thyroid (1.22; CI 1.01 to 1.48), pleura (1.60; CI 1.09 to 2.34), and for malignant melanoma (1.21; CI 1.02 to 1.45). We found significant SMREs of 1.36 (1.18 to 1.57) and 1.42 (1.05 to 1.90) for rectal cancer and Non‐Hodgkin's lymphoma, respectively. Considering the significantly elevated risk of some cancers in this occupational group, we suggest improving preventive measures and securing adequate and relevant medical attention for this group. Further studies with more accurate and in‐depth exposure assessments are indicated.

Cancer risk among career male and female Florida firefighters: Evidence from the Florida Firefighter Cancer Registry (1981‐2014)

“…Female firefighters were at increased risk of thyroid and brain cancer with some evidence for increased risk of melanoma which approached statistical significance (aOR = 1.68; 95% CI: 0.97‐2.90). These risks were higher than pooled estimates reported in the recently published meta‐analysis by Jalilian et al, 6 which was largely based on analysis of individual studies of male firefighters, or those that pooled findings for male and female firefighters. For example, risk of thyroid cancer was markedly higher in male and female Florida firefighters (2.17; 1.78‐2.66, and 2.42; 1.56‐3.74) relative to the summary incidence risk estimate (SIRE) reported in the meta‐analysis (SIRE = 1.22; 95% CI: 1.01‐1.48) 6 …”

“…One possible explanation for these differences is that the present analysis employed a case‐control analytic method while a number of papers included in the Jalilian meta‐analysis compared firefighter incidence rates with general population incidence rates 6 . As indicated earlier, this latter approach can be more susceptible to underestimating true risk given the healthy worker effect 24,32 .…”

“…As indicated earlier, this latter approach can be more susceptible to underestimating true risk given the healthy worker effect 24,32 . Of note, nine of the 29 cancer incidence studies included in the Jalilian meta‐analysis calculations, 6 including the initial Florida analysis, 19 employed national or regional comparators in their SIR calculations (see Table S5) 6 …”

“…Numerous epidemiologic studies have subsequently examined cancer incidence and mortality risk among firefighters resulting in the publication of several reviews and meta‐analyses of this literature 1,4,5 . A 2019 meta‐analysis pooled incidence data from 29 studies representing over 30 000 mostly male firefighters from 11 countries, making it the most comprehensive review to date 6 . Due to the small number of female firefighters, extracted effect sizes were limited to males or presented as combined effect sizes for males and females.…”

Author's Reply to: Cancer incidence and mortality among firefighters

“…1 At first, the letter presents a short summary of main results and then comments on the findings for incidence and mortality separately. 1 At first, the letter presents a short summary of main results and then comments on the findings for incidence and mortality separately.…”