United Fire Service Women

Given the complex exposures from both exogenous and endogenous sources that an individual experiences during life, exposome-wide association studies that interrogate levels of small molecules in biospecimens have been proposed for discovering causes of chronic diseases. We conducted a study to explore associations between environmental chemicals and endogenous molecules using Gaussian graphical models (GGMs) of non-targeted metabolomics data measured in a cohort of California women firefighters and office workers. GGMs revealed many exposure-metabolite associations, including that exposures to mono-hydroxyisononyl phthalate, ethyl paraben and 4-ethylbenzoic acid were associated with metabolites involved in steroid hormone biosynthesis, and perfluoroalkyl substances were linked to bile acids—hormones that regulate cholesterol and glucose metabolism—and inflammatory signaling molecules. Some hypotheses generated from these findings were confirmed by analysis of data from the National Health and Nutrition Examination Survey. Taken together, our findings demonstrate a novel approach to discovering associations between chemical exposures and biological processes of potential relevance for disease causation.

Abstract BackgroundStudies in male firefighters have demonstrated increased exposures to carcinogenic compounds and increased rates of certain cancers compared to the general population. Many chemicals related to these occupational exposures have been associated with breast tumor development in animal and human studies, yet, there have been no studies on women firefighters due to their low numbers in most fire departments. To address this data gap, the Women Firefighters Biomonitoring Collaborative (WFBC) created a biological sample archive and analyzed levels of perfluoroalkyl substances (PFAS) among women firefighters and office workers in San Francisco.MethodsActive duty women firefighters (n=86) and office workers (n=84) were recruited from the San Francisco Fire Department and the City and County of San Francisco, respectively. Serum samples were collected and analyzed using liquid chromatography tandem mass spectrometry (LC MS/MS) to measure and compare PFAS levels between firefighters and office workers. For PFAS congeners detected in at least 70% of our study population, we examined differences in serum PFAS levels controlling for dietary, demographic and other confounders. Among firefighters, we assessed associations between occupational activities and PFAS levels.ResultsEight of 12 PFAS congeners were detected at levels above the limit of detection and seven were detected in at least 70% of the study population. Four PFAS were detected in all study participants (PFNA, PFOA, PFOS, PFHxS). In regression models comparing PFAS levels by occupation and adjusting for potential confounders, firefighters had higher geometric mean (GM) concentrations of PFAS compared to office workers: 2.39 (95%CI = 1.64,3.48), 2.32 (95% CI = 1.17,4.62) and 1.26 (95% CI = 0.99, 1.59) times higher for PFHxS, PFUnDA and PFNA, respectively. In analyses limited to firefighters, PFAS levels varied by assigned position in the fire department—firefighters and officers had higher PFNA, PFOA, PFDA, and PFUnDA compared to drivers. Additionally, firefighters who reported having used firefighting foam had higher concentrations of PFOA compared firefighters who reported never having used foam.ConclusionOur study found ubiquitous exposures to PFAS among WFBC participants, with women firefighters exposed to higher levels of some PFAS compared to office workers, suggesting that some of these exposures may be occupationally related.

Occupational studies indicate that firefighters are at higher risk for different types of cancers than the general population, and concern has mounted about elevated rates of premenopausal breast cancer among women firefighters. The Women Firefighters Biomonitoring Collaborative (WFBC) is a community-based participatory research project analyzing exposures to environmental chemicals linked to breast cancer among female firefighters in San Francisco (SF) compared to non-firefighters. As scientific partners in the WFBC, women firefighters have been involved in study design, data collection, and results communication. Between 2013 and 2014 we recruited 86 women firefighters and 84 office workers employed in San Francisco, conducted an exposure assessment interview, and collected blood samples. We conducted targeted analysis for 12 perfluoroalkyl substances (PFAS) using liquid chromatography-tandem mass spectrometry. We detected seven compounds in over 70% of participants at levels above the level of detection (LOD 0.02-0.05 ng/ml), five of which were detected in 98 -100% of participants. Multivariate models showed that firefighters had a 1.53 and 2.19 times higher concentration of PFNA and PFHxS respectively, compared to non-firefighters. Among firefighters only, multivariate models showed increased concentration of PFNA, PFOA, PFOS and PFUnDA for firefighters aged 50 years or older, and higher PFOA levels among firefighters who reported ever using firefighting foam. Additionally, PFHxS levels were higher among those who “rarely” used personal protective equipment (PPE) compared to those who reported “always/often” using PPE. Our results indicate that women firefighters have higher levels of some PFAS compared to office workers, and that these exposures may be associated with firefighting foam and PPE use.Further research is needed to understand the health implications, particularly for breast cancer risk, of these exposures.