Mortality in a cohort of US firefighters from San Francisco, Chicago and Philadelphia: an update

Abstract

ObjectivesTo 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.MethodsVital 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.ResultsCompared 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).ConclusionsThis 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.

Mortality among Fire Department of the City of New York Rescue and Recovery Workers Exposed to the World Trade Center Disaster, 2001–2017

“…Furthermore, the impact of the healthy worker effect in the FDNY population may not allow our results to be generalizable to other WTC-exposed cohorts. While we found lower mortality than a study of non-WTC-exposed US firefighters, we suspect that some of the differences in SMRs from those of the FDNY may be explained, in part, by the earlier average year of hire and longer follow-up time since hire of the non-WTC-exposed US firefighters [ 28 ]. This indicates an older population that is farther from the point of workforce entry and therefore, likely to have experienced a diminution of the healthy worker effect, bringing their mortality rates closer to that of the US general population.…”

“…Expected associations for well-established risk factors of premature mortality in our cohort provide confidence in our results. For example, SMRs of the cause-specific minor categories were overwhelmingly lower than expected compared with the general population, with the exception of non-significant but elevated rates of death from a building fire (SMR = 1.29), not surprising given that our population was nearly 89% firefighters, and mesothelioma (SMR = 1.71), which has been reported as elevated among firefighters compared with the general population [ 28 , 38 ]. Secondly, as was emphasized through SMR stratification by WTC-exposure, our cox proportional hazards analyses demonstrated that WTC-exposure intensity was not related to mortality risk while more typical risk factors such as being male, cigarette smoking, and older age conferred increased risk.…”

“…All-cause and cause-specific SMRs were examined overall and stratified by race (non-Hispanic white, non-white), work assignment (firefighters, EMS), and WTC-exposure (high, moderate/low). All LTAS major causes of death were reported and minor causes of death were chosen a priori based on the results of previous studies [ 17 , 28 ] and knowledge of the cohort. Minor causes of death were: human immunodeficiency virus (HIV), malignant neoplasms of the esophagus, pancreas, trachea/bronchus/lung, melanoma, mesothelioma, and the brain and other parts of the nervous system; non-Hodgkin’s lymphoma, multiple myeloma, benign and unspecified neoplasms of the eye, brain, and other parts of the nervous system, alcoholism, other nervous system diseases, rheumatic heart disease, hypertension with heart disease, ischemic heart disease, cerebrovascular disease, hypertension without heart disease, diseases of the arteries/veins/lymph nodes, pneumonia, chronic obstructive pulmonary disease (COPD), hernia and intestinal obstruction, chronic and unspecified renal failure, motor vehicle (-driver, -pedestrian), fire in a building, accidental poisoning, intentional self-harm (hereafter, this LTAS category (minor cause 116) referred to as “suicide”), and assault and homicide.…”

Organophosphate and organohalogen flame-retardant exposure and thyroid hormone disruption in a cohort of female firefighters and office workers from San Francisco

“…Breast cancer incidence was non-significantly elevated among men and among the 991 women included in the study and in both groups the increases were largest among those at younger ages (<65 years old for men and ages 50-55 for women (Daniels et al 2014)). In a published update adding 7 years of follow up to the pooled cohort, Pinkerton et al (2020) found that women firefighters had elevated mortality rates for bladder cancer and non-statistically elevated mortality from Non-Hodgkin's lymphoma, multiple myeloma, lung cancer and breast cancer (Pinkerton et al 2020). A study of Florida firefighters that included 5,000…”

“…Breast cancer incidence was non-significantly elevated among men and among the 991 women included in the study and in both groups the increases were largest among those at younger ages (<65 years old for men and ages 50-55 for women (Daniels et al 2014)). In a published update adding 7 years of follow up to the pooled cohort, Pinkerton et al (2020) found that women firefighters had elevated mortality rates for bladder cancer and non-statistically elevated mortality from Non-Hodgkin’s lymphoma, multiple myeloma, lung cancer and breast cancer (Pinkerton et al 2020). A study of Florida firefighters that included 5,000 women found elevated incidence of cervical and thyroid cancer and Hodgkin’s disease compared to the general Florida population (Ma et al 2006) and a more recent study of Florida firefighters using that state’s cancer registry found that women firefighters had elevated risk of melanoma, thyroid, and brain cancer (Lee et al 2020).…”