Selenium modifies associations between multiple metals and neurologic symptoms in Gulf states residents

Background: Metals have been shown to have a wide range of neurologic effects across the life course, but most studies consider neurodevelopment or neurodegenerative diseases in older adults. We investigated exposure to metals during adulthood in association with subclinical neurologic endpoints, considering the metals individually and as a mixture, and potential interactions among exposures. Methods: We measured blood levels of cadmium, lead, mercury, manganese, and selenium in 1007 Gulf state residents and estimated cross-sectional associations between ranked levels of blood metals and the presence of self-reported neurologic symptoms. Single pollutant models were mutually adjusted for other metals and we used quantile g-computation to evaluate associations with exposure to the combined mixture. In stratified analyses, we assessed heterogeneity by smoking and blood selenium. Results: The highest quartile of cadmium was associated with a higher prevalence of central nervous system symptoms (prevalence ratio [PR] = 1.50; 95% confidence interval [CI] = 1.13, 1.99), with stronger associations among nonsmokers (PR = 1.63; 95% CI = 1.11, 2.38) and those with low selenium (PR = 2.29, 95% CI = 1.50, 3.49). Selenium also modified associations between lead and peripheral nervous system symptoms, with increased symptoms in the low selenium group at all quartiles of exposure (P-trend = 0.07). Conversely, those with the highest co-exposure to mercury and selenium had reduced neurologic symptoms (PR = 0.73, 95% CI = 0.55, 0.96). Results of the mixture analysis were consistent with single chemical results. Conclusions: Cadmium exhibited the most consistent relationship with increased neurologic symptoms, though lead was an important exposure in subgroup analyses. Selenium may modify subclinical neurotoxic effects of metals at non-occupational levels in adults

Associations between blood BTEXS concentrations and hematologic parameters among adult residents of the U.S. Gulf States

Background Studies of workers exposed to benzene at average air concentrations below one part per million suggest that benzene, a known hematotoxin, causes hematopoietic damage even at low exposure levels. However, evidence of such effects outside of occupational settings and for other volatile organic compounds (VOCs) is limited. Objective To investigate associations between ambient exposures to five VOCs, including benzene, and hematologic parameters among adult residents of the U.S. Gulf Coast. Materials and methods Blood concentrations of selected VOCs were measured in a sample of adult participants in the Gulf Long-term Follow-up Study (GuLF STUDY) during 2012 and 2013. Complete blood counts with differentials were also performed on a subset of participants (n=406). We used these data together with detailed questionnaire data to estimate adjusted associations between blood BTEXS (benzene, toluene, ethylbenzene, o-xylene, m/p-xylene, and styrene) concentrations and hematologic parameters using generalized linear models. Results We observed inverse associations between blood benzene concentrations and hemoglobin concentration and mean corpuscular hemoglobin concentration, and a positive association with red cell distribution width among tobacco smoke-unexposed participants (n=146). Among tobacco smoke-exposed participants (n=247), we observed positive associations between blood VOC concentrations and several hematologic parameters, including increased white blood cell and platelet counts, suggestive of hematopoietic stimulation typically associated with tobacco smoke exposure. Most associations were stronger for benzene than for the other VOCs. Conclusions Our results suggest that ambient exposure to BTEXS, particularly benzene, may be associated with hematologic effects, including decreased hemoglobin concentration, mean corpuscular hemoglobin concentration, and increased red cell distribution width

The Gulf Long-Term Follow-Up Study (GuLF STUDY): Biospecimen collection at enrollment

The 2010 Deepwater Horizon (DWH) explosion in the Gulf of Mexico led to the largest ever marine oil spill by volume. The GuLF STUDY is investigating possible adverse human health effects associated with oil spill activities. One objective of the study was to utilize biological specimens from study participants to examine spill-related adverse health effects. This study describes the methods for collecting, processing, shipping, and storing specimens during the enrollment phase of the study. GuLF STUDY participants living in Gulf States (Alabama, Florida, Louisiana, Mississippi, and eastern Texas) were eligible to complete a home visit at enrollment, one to three years after the DWH explosion. During this visit, blood, urine, toenail and hair clippings, and house dust samples were collected. Specimens were shipped overnight to a central processing laboratory in containers with cold and ambient temperature compartments. Most blood and urine specimens were then aliquoted and stored in liquid nitrogen vapor or at -80°C, with some samples stored at -20°C. A total of 11,193 participants completed a home visit, and over 99% provided at least one biospecimen. Most participants provided blood (93%), urine (99%), and toenail clippings (89%), and 40% provided hair. Nearly all participants (95%) provided house-dust samples. Most samples were received by the laboratory one (58%) or two (25%) days after collection. These biospecimens enable investigation of a range of biomarkers of spill-related adverse health effects, and possibly some biomarkers of spill-related exposures. The biospecimen collection, handling, and storage protocols were designed to maximize current and future scientific value within logistical and budgetary constraints and might serve as a template for future studies conducted in similar time-critical and geographically dispersed settings

Spirometry quality predictors in a large multistate prospective study

Background: The Gulf Long-Term Follow-up (GuLF) Study is a prospective cohort study of health effects associated with oil spill response and clean-up following the 2010 Deepwater Horizon Disaster (DWH). As part of the study, spirometry testing of lung function was carried out in home visits across multiple states. Few studies have described factors associated with spirometry test failure in field-based settings. Objective: Our objective was to identify what factors, if any, predict test failure among GuLF Study participants who completed spirometry testing in a non-traditional setting. Methods: Trained examiners administered spirometry (May 2011–May 2013) to 10,019 participants living in US Gulf States (LA, MS, TX, AL, FL) using an Easy-on ultrasonic spirometer. We applied American Thoracic Society/European Respiratory Society quality criteria to determine quality test failure and identified factors predictive of failure using both a Stepwise and a LASSO model. We calculated odds ratios and 95% confidence intervals (CIs) for associations of selected factors with test failure. Results: Among GuLF Study participants who conducted spirometry, self-reported African American/Black participants (OR: 1.39, 95% CI: 1.23,1.56); men (OR:1.61, 95% CI: 1.41,1.83); and those making less than $20,000 per year (OR: 1.45, 95% CI: 1.26,1.67) were more likely to fail quality testing, while those who were obese were less likely to fail (OR: 0.61, 95% CI: 0.42,0.89). Conclusion: Field-based studies involving spirometry should identify and account for participant factors that may influence test failure. Coaching that is tailored to those less likely to have experience with spirometry may help reduce test failure rates

Developing Large-Scale Research in Response to an Oil Spill Disaster: a Case Study

Research conducted in the wake of a disaster can provide information to help mitigate health consequences, support future recovery efforts, and improve resilience. However, a number of barriers have prevented time-sensitive research responses following previous disasters. Furthermore, large-scale disasters present their own special challenges due to the number of people exposed to disaster conditions, the number of groups engaged in disaster response, and the logistical challenges of rapidly planning and implementing a large study. In this case study, we illustrate the challenges in planning and conducting a large-scale post-disaster research study by drawing on our experience in establishing the Gulf Long-term Follow-up (GuLF) Study following the 2010 Deepwater Horizon disaster. We describe considerations in identifying at-risk populations and appropriate comparison groups, garnering support for the study from different stakeholders, obtaining timely scientific and ethics review, measuring and characterizing complex exposures, and addressing evolving community health concerns and unmet medical needs. We also describe the NIH Disaster Research Response (DR2) Program, which provides a suite of resources, including data collection tools, research protocols, institutional review board guidance, and training materials to enable the development and implementation of time-critical studies following disasters and public health emergencies. In describing our experiences related to the GuLF Study and the ongoing efforts through the NIH DR2 Program, we aim to help improve the timeliness, quality, and value of future disaster-related data collection and research studies

Mental health indicators associated with oil spill response and clean-up: cross-sectional analysis of the GuLF STUDY cohort

Background Adverse mental health effects have been reported following oil spills but few studies have identified specific responsible attributes of the clean-up experience. We aimed to analyse the effects of the 2010 Deepwater Horizon (Gulf of Mexico) disaster on the mental health of individuals involved in oil spill response and clean-up. Methods We used data from the Gulf Long-term Follow-up Study, a cohort of workers and volunteers involved in oil spill clean-up after the Deepwater Horizon disaster. We included 8968 workers (hired after completing training for oil spill response and clean-up) and 2225 non-workers (completed training but were not hired) who completed a Patient Health Questionnaire-8 and four-item Primary Care PTSD Screen to assess for probable depression and post-traumatic stress disorder (PTSD) indicators. Participants were recruited between March 28, 2011, and March 29, 2013. The mental health indicators were assessed at home visits done between May 12, 2011, and May 15, 2013. We used regression models to analyse the effect of potentially stressful job experiences, job type, and total hydrocarbon exposure on mental health indicators. Findings Oil spill response and clean-up work was associated with increased prevalence of depression (prevalence ratio [PR] 1·22, 95% CI 1·08–1·37) and PTSD (PR 1·35, 95% CI 1·07–1·71). Among workers, individuals who reported smelling oil, dispersants, or cleaning chemicals had an elevated prevalence of depression (1·56, 1·37–1·78) and PTSD (2·25, 1·71–2·96). Stopping work because of the heat was also associated with depression (1·37, 1·23–1·53) and PTSD (1·41, 1·15–1·74), as was working as a commercial fisherman before the spill (1·38, 1·21–1·57; and 2·01, 1·58–2·55, respectively). An increase in exposure to total hydrocarbons appeared to be associated with depression and PTSD, but after taking into account oil spill job experiences, only the association between the highest amount of total hydrocarbons and PTSD remained (1·75, 1·11–2·76). Interpretation Oil spill clean-up workers with high amounts of total hydrocarbon exposure or potentially stressful job experiences had an increased prevalence of depression and PTSD. These findings provide evidence that response and clean-up work is associated with adverse psychological effects and suggest the need for mental health services both before and after the event. Funding National Institutes of Health (NIH) Common Fund and the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences

Association between Deepwater Horizon oil spill response and cleanup work experiences and lung function

Introduction: Oil spill response and cleanup (OSRC) workers had potentially stressful experiences during mitigation efforts following the 2010 Deepwater Horizon disaster. Smelling chemicals; skin or clothing contact with oil; heat stress; handling oily plants/wildlife or dead animal recovery; and/or being out of regular work may have posed a risk to worker respiratory health through psychological stress mechanisms. Objective: To evaluate the association between six potentially stressful oil spill experiences and lung function among OSRC workers 1–3 years following the Deepwater Horizon disaster, while controlling for primary oil spill inhalation hazards and other potential confounders. Methods: Of 6811 GuLF STUDY participants who performed OSRC work and completed a quality spirometry test, 4806 provided information on all exposures and confounders. We carried out complete case analysis and used multiple imputation to assess risk among the larger sample. Potentially stressful work experiences were identified from an earlier study of these workers. The lung function parameters of interest include the forced expiratory volume in 1 s (FEV1, mL), the forced vital capacity (FVC, mL) and the ratio (FEV1/FVC, %). Results: On average, participants in the analytic sample completed spirometry tests 1.7 years after the spill. Among workers with at least 2 acceptable FEV1 and FVC curves, workers with jobs that involved oily plants/wildlife or dead animal recovery had lower values for FEV1 (Mean difference: −53 mL, 95% CI: −84, −22), FVC (Mean difference: −45 mL, 95% CI: −81, −9) and FEV1/FVC (Mean difference: −0.44%, 95% CI: −0.80, −0.07) compared to unexposed workers in analyses using multiple imputation. Conclusions: Workers involved in handling oily plants/wildlife or dead animal recovery had lower lung function than unexposed workers after accounting for other OSRC inhalation hazards

Predictors of blood volatile organic compound levels in Gulf coast residents article

To address concerns among Gulf Coast residents about ongoing exposures to volatile organic compounds, including benzene, toluene, ethylbenzene, o-xylene, and m-xylene/p-xylene (BTEX), we characterized current blood levels and identified predictors of BTEX among Gulf state residents. We collected questionnaire data on recent exposures and measured blood BTEX levels in a convenience sample of 718 Gulf residents. Because BTEX is rapidly cleared from the body, blood levels represent recent exposures in the past 24 h. We compared participants' levels of blood BTEX to a nationally representative sample. Among nonsmokers we assessed predictors of blood BTEX levels using linear regression, and predicted the risk of elevated BTEX levels using modified Poisson regression. Blood BTEX levels in Gulf residents were similar to national levels. Among nonsmokers, sex and reporting recent smoky/chemical odors predicted blood BTEX. The change in log benzene was -0.26 (95% CI: -0.47, -0.04) and 0.72 (0.02, 1.42) for women and those who reported odors, respectively. Season, time spent away from home, and self-reported residential proximity to Superfund sites (within a half mile) were statistically associated with benzene only, however mean concentration was nearly an order of magnitude below that of cigarette smokers. Among these Gulf residents, smoking was the primary contributor to blood BTEX levels, but other factors were also relevant

Exposure to Oil Spill Chemicals and Lung Function in Deepwater Horizon Disaster Response Workers

Objective: The aim of this study was to assess the relationship between total hydrocarbon (THC) exposures attributed to oil spill clean-up work and lung function 1 to 3 years after the Deepwater Horizon (DWH) disaster. Methods: We used data from the GuLF STUDY, a large cohort of adults who worked on response to the DWH disaster and others who were safety trained but did not work. We analyzed data from 6288 workers with two acceptable spirometry tests. We estimated THC exposure levels with a job exposure matrix. We evaluated lung function using the forced expiratory volume in 1second (FEV 1; mL), the forced vital capacity (FVC; mL), and the FEV 1 /FVC ratio (%). Results: Lung function measures did not differ by THC exposure levels among clean-up workers. Conclusion: We did not observe an association between THC exposure and lung function among clean-up workers 1 to 3 years following the DWH disaster

Lung function in oil spill responders 4-6 years after the Deepwater Horizon disaster

Oil spill response and clean-up (OSRC) workers were exposed to hazardous airborne chemicals following the 2010 Deepwater Horizon disaster. The aim of this study was to evaluate lung function in workers 4–6 years following the disaster using a prospective cohort. Participants who completed two spirometry test sessions 1–3 years, and 4–6 years after the spill (N = 1,838) were included and forced expiratory volume in 1 s (FEV1; ml), forced vital capacity (FVC; ml), and ratio (FEV1/FVC; %) determined. Linear mixed models were utilized to estimate relationships between OSRC exposures and lung function 4–6 years after the spill and changes since the prior measurement. Despite suggestive reduced lung function at 1–3 years, at the 4–6-year exam workers with total hydrocarbon (THC) exposure 1–2.99 ppm and ≥3 ppm compared to those with ≤0.29 ppm exhibited higher FEV1 (β: 108 ml, 95% CI: 17, 198) and (β: 118 ml, 95% CI: 5, 232), respectively. Compared with support workers, those in higher exposed jobs displayed greater improvement in FEV1 between visits: cleanup on water (β: 143 ml, 95% CI: 35, 250), operations (β: 132 ml, 95% CI: 30, 234) and response (β: 149 ml, 95% CI: 43, 256). Greater FEV1 improvement was also associated with higher versus the lowest level THC exposure: 1–2.99 ppm (β: 134 ml, 95% CI: 57, 210) and ≥3 ppm (β: 205 ml, 95% CI: 109, 301). Lung function decrements seen shortly after the spill were no longer apparent 4–6 years later, with the greatest improvement among those with the highest exposures