Occupation, Environment, and Mental Health

Abstract

Despite a decades-old call for better understanding of the role of environmental pollutant influences on mental health, a comprehensive review of the literature on non-occupational exposures to environmental pollutants and adult mental health has not been performed. Second, the Germanwings Flight 9525 crash has brought the sensitive subject of airline pilot mental health to the forefront in aviation. Third, scientists use biomarkers to evaluate metal exposures. One biomarker, toenails, is easily obtained and minimally invasive, but less commonly used as a biomarker of exposure. Their utility will depend on understanding characteristics of their variation in a population over time. Fourth, toenails are less commonly used as a biomarker of exposure and has not been evaluated on its relationship with psychiatric outcomes; particularly depression and anxiety. We reviewed the existing literature on environmental pollutant exposures and three specific mental health outcomes (depression, anxiety, and suicide) published on PubMed, Embase, Web of Science, and PsychINFO through the end of year 2016. Second, we conducted a descriptive cross-sectional study via an anonymous web-based survey administered to airline pilots between April and December 2015. Third, we utilized linear mixed models to assess correlation between toenail metal concentrations in multiple toenail samples from the same subject collected years apart among participants in the VA Normative Aging Study (NAS). Fourth, we utilized multivariate linear and logistic mixed models to assess the association with five toenail metals and outcomes measured by the Brief Symptom Index (BSI). The current literature, although limited, clearly suggests many kinds of environmental exposures may be risk factors for depression, anxiety, and suicide. Overall, the strongest studies appear to be of air pollution exposure. Second, hundreds of pilots currently flying are managing depressive symptoms perhaps without the possibility of treatment due to the fear of negative career impacts. Third, our results suggest that lead, arsenic, cadmium, manganese, and mercury levels from toenail clippings can reasonably reflect exposures over several years in elderly men in the NAS. Fourth, our study tentatively suggests that toenails from NAS participants may be an important biomarker to measure the association between metals and symptoms of depression or anxiety.