Risk of longer-term neurological conditions in the Deepwater Horizon Oil Spill Coast Guard Cohort Study - Five years of follow-up.

BACKGROUND: Long-term neurological health risks associated with oil spill cleanup exposures are largely unknown. We aimed to investigate risks of longer-term neurological conditions among U.S. Coast Guard (USCG) responders to the 2010 Deepwater Horizon (DWH) oil spill. METHODS: We used data from active duty members of the DWH Oil Spill Coast Guard Cohort Study (N=45224). Self-reported oil spill exposures were ascertained from post-deployment surveys. Incident neurological outcomes were classified using International Classification of Diseases, 9th Revision, codes from military health encounter records up to 5.5 years post-DWH. We used Cox Proportional Hazards regression to calculate adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for various incident neurological diagnoses (2010-2015). Oil spill responder (n=5964) vs. non-responder (n= 39260) comparisons were adjusted for age, sex, and race, while within-responder comparisons were additionally adjusted for smoking. RESULTS: Compared to those not responding to the spill, spill responders had reduced risks for headache (aHR=0.84, 95% CI: 0.74-0.96), syncope and collapse (aHR=0.74, 95% CI: 0.56-0.97), and disturbance of skin sensation (aHR=0.81, 95% CI: 0.68-0.96). Responders reporting ever (n=1068) vs. never (n=2424) crude oil inhalation exposure were at increased risk for several individual and grouped outcomes related to headaches and migraines (aHR range: 1.39-1.83). Crude oil inhalation exposure was also associated with elevated risks for an inflammatory nerve condition, mononeuritis of upper limb and mononeuritis multiplex (aHR=1.71, 95% CI: 1.04-2.83), and tinnitus (aHR=1.91, 95% CI: 1.23-2.96), a condition defined by ringing in one or both ears. Risk estimates for those neurological conditions were higher in magnitude among responders reporting exposure to both crude oil and oil dispersants than among those reporting crude oil only. CONCLUSION: In this large study of active duty USCG responders to the DWH disaster, self-reported spill cleanup exposures were associated with elevated risks for longer-term neurological conditions.

Risk factors for acute mental health symptoms and tobacco initiation in Coast Guard Responders to the Deepwater Horizon oil spill.

Acute mental health symptoms experienced during oil spill response work are understudied, especially among nonlocal responders. We assessed potential risk factors for acute mental health symptoms and tobacco initiation among U.S. Coast Guard responders to the 2010 Deepwater Horizon (DWH) oil spill who completed a deployment exit survey. Cross-sectional associations among responder characteristics, deployment-related stressors (deployment duration, timing, crude oil exposure, physical symptoms, injuries), and professional help-seeking for stressors experienced with concurrent depression/anxiety and tobacco initiation were examined. Log-binomial regression was used to calculate adjusted prevalence ratios (aPRs) and 95% confidence intervals. Sensitivity analyses excluded responders with a history of mental health conditions using health encounter data from the Military Health System Data Repository. Of the 4,855 responders, 75.5% were deployed from nonlocal/non-Gulf home stations, 5.8% reported concurrent depression and anxiety, and 2.8% reported the initiation of any tobacco product during oil spill response. Self-report of concurrent depression and anxiety was more prevalent among female responders and positively associated with longer deployments, crude oil exposure via inhalation, physical symptoms and injuries, and professional help-seeking during deployment, aPRs = 1.54-6.55. Tobacco initiation was inversely associated with older age and officer rank and positively associated with deployment-related stressors and depression/anxiety during deployment, aPRs = 1.58-4.44. Associations remained robust after excluding responders with a history of mental health- and tobacco-related health encounters up to 3 years before deployment. Depression, anxiety, and tobacco initiation were cross-sectionally associated with oil spill response work experiences among DWH responders, who largely originated outside of the affected community.

Acute and longer-term cardiovascular conditions in the Deepwater Horizon Oil Spill Coast Guard Cohort.

INTRODUCTION: In 2010, the U.S. Coast Guard (USCG) led a clean-up response to the Deepwater Horizon (DWH) oil spill. Human studies evaluating acute and longer-term cardiovascular conditions associated with oil spill-related exposures are sparse. Thus, we aimed to investigate prevalent and incident cardiovascular symptoms/conditions in the DHW Oil Spill Coast Guard Cohort. METHODS: Self-reported oil spill exposures and cardiovascular symptoms were ascertained from post-deployment surveys (n = 4,885). For all active-duty cohort members (n = 45,193), prospective cardiovascular outcomes were classified via International Classification of Diseases, 9th Edition from military health encounter records up to 5.5 years post-DWH. We used log-binomial regression to calculate adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) in the cross-sectional analyses and Cox Proportional Hazards regression to calculate adjusted hazard ratios (aHR) and 95% CIs for incident cardiovascular diagnoses during 2010-2015 and stratifying by earlier (2010-2012) and later (2013-2015) time periods. RESULTS: Prevalence of chest pain was associated with increasing levels of crude oil exposure via inhalation (aPRhigh vs. none = 2.00, 95% CI = 1.16-3.42, p-trend = 0.03) and direct skin contact (aPRhigh vs. none = 2.72, 95% CI = 1.30-5.16, p-trend = 0.03). Similar associations were observed for sudden heartbeat changes and for being in the vicinity of burning oil exposure. In prospective analyses, responders (vs. non-responders) had an elevated risk for mitral valve disorders during 2013-2015 (aHR = 2.12, 95% CI = 1.15-3.90). Responders reporting ever (vs. never) crude oil inhalation exposure were at increased risk for essential hypertension, particularly benign essential hypertension during 2010-2012 (aHR = 2.00, 95% CI = 1.08-3.69). Responders with crude oil inhalation exposure also had an elevated risk for palpitations during 2013-2015 (aHR = 2.54, 95% CI = 1.36-4.74). Cardiovascular symptoms/conditions aPR and aHR estimates were generally stronger among responders reporting exposure to both crude oil and oil dispersants than among those reporting neither. CONCLUSIONS: In this large study of the DWH oil spill USCG responders, self-reported spill clean-up exposures were associated with acute and longer-term cardiovascular symptoms/conditions.

Incidence of chronic respiratory conditions among oil spill responders: Five years of follow-up in the Deepwater Horizon Oil Spill Coast Guard Cohort study.

BACKGROUND: Over ten years after the Deepwater Horizon (DWH) oil spill, our understanding of long term respiratory health risks associated with oil spill response exposures is limited. We conducted a prospective analysis in a cohort of U.S. Coast Guard personnel with universal military healthcare. METHODS: For all active duty cohort members (N = 45,193) in the DWH Oil Spill Coast Guard Cohort Study we obtained medical encounter data from October 01, 2007 to September 30, 2015 (i.e., ~2.5 years pre-spill; ~5.5 years post-spill). We used Cox Proportional Hazards regressions to calculate adjusted hazard ratios (aHR), comparing risks for incident respiratory conditions/symptoms (2010-2015) for: responders vs. non-responders; responders reporting crude oil exposure, any inhalation of crude oil vapors, and being in the vicinity of burning crude oil versus responders without those exposures. We also evaluated self-reported crude oil and oil dispersant exposures, combined. Within-responder comparisons were adjusted for age, sex, and smoking. RESULTS: While elevated aHRs for responder/non-responder comparisons were generally weak, within-responder comparisons showed stronger risks with exposure to crude oil. Notably, for responders reporting exposure to crude oil via inhalation, there were elevated risks for allsinusitis (aHR = 1.48; 95%CI, 1.06-2.06), unspecified chronic sinusitis (aHR = 1.55; 95%CI, 1.08-2.22), chronic obstructive pulmonary disease (COPD) and other allied conditions (aHR = 1.43; 95%CI, 1.00-2.06), and dyspnea and respiratory abnormalities (aHR = 1.29; 95%CI, 1.00-1.67); there was a suggestion of elevated risk for diseases classified as asthma and reactive airway diseases (aHR = 1.18; 95%CI, 0.98-1.41), including the specific condition, asthma (aHR = 1.35; 95%CI, 0.80-2.27), the symptom, shortness of breath (aHR = 1.50; 95%CI, 0.89-2.54), and the overall classification of chronic respiratory conditions (aHR = 1.18; 95%CI, 0.98-1.43). Exposure to both crude oil and dispersant was positively associated with elevated risk for shortness of breath (HR = 2.24; 95%CI, 1.09-4.64). CONCLUSIONS: Among active duty Coast Guard personnel, oil spill clean-up exposures were associated with moderately increased risk for longer term respiratory conditions.

A review of the toxicology of oil in vertebrates: what we have learned following the Deepwater Horizon oil spill.

In the wake of the Deepwater Horizon (DWH) oil spill, a number of government agencies, academic institutions, consultants, and nonprofit organizations conducted lab- and field-based research to understand the toxic effects of the oil. Lab testing was performed with a variety of fish, birds, turtles, and vertebrate cell lines (as well as invertebrates); field biologists conducted observations on fish, birds, turtles, and marine mammals; and epidemiologists carried out observational studies in humans. Eight years after the spill, scientists and resource managers held a workshop to summarize the similarities and differences in the effects of DWH oil on vertebrate taxa and to identify remaining gaps in our understanding of oil toxicity in wildlife and humans, building upon the cross-taxonomic synthesis initiated during the Natural Resource Damage Assessment. Across the studies, consistency was found in the types of toxic response observed in the different organisms. Impairment of stress responses and adrenal gland function, cardiotoxicity, immune system dysfunction, disruption of blood cells and their function, effects on locomotion, and oxidative damage were observed across taxa. This consistency suggests conservation in the mechanisms of action and disease pathogenesis. From a toxicological perspective, a logical progression of impacts was noted: from molecular and cellular effects that manifest as organ dysfunction, to systemic effects that compromise fitness, growth, reproductive potential, and survival. From a clinical perspective, adverse health effects from DWH oil spill exposure formed a suite of signs/symptomatic responses that at the highest doses/concentrations resulted in multi-organ system failure.

Neurological symptoms associated with oil spill response exposures: Results from the Deepwater Horizon Oil Spill Coast Guard Cohort Study.

INTRODUCTION: The Deepwater Horizon (DWH) oil spill was the largest marine oil spill in U.S. history, involving the response of tens of thousands clean-up workers. Over 8500 United States Coast Guard personnel were deployed in response to the spill. Little is understood about the acute neurological effects of oil spill clean-up-related exposures. Given the large number of people involved in large oil spill clean-ups, study of these effects is warranted. METHODS: We utilized exposure, health, and lifestyle data from a post-deployment survey administered to Coast Guard responders to the DWH oil spill. Crude oil exposure was assessed via self-reported inhalation and skin contact metrics, categorized by frequency of self-reported exposure to crude oil during deployment (never, rarely, sometimes, most/all of the time). Combined exposure to crude oil and oil dispersant was also evaluated. Adjusted log binomial regressions were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CI), investigating the associations between oil spill exposures and neurological symptoms during deployment. Stratified analyses investigated potential effect modification by sex, exhaust fume exposure, personal protective equipment (PPE) use, and deployment duration and timing. RESULTS: Increasing frequency of crude oil exposure via inhalation was associated with increased likelihood of headaches (PRmost/all vs. never = 1.80), lightheadedness (PRmost/all vs. never = 3.36), difficulty concentrating (PRmost/all vs. never = 1.72), numbness/tingling sensation (PRmost/all vs. never = 3.32), blurred vision (PRmost/all vs. never = 2.87), and memory loss/confusion (PRmost/all vs. never = 2.03), with significant tests for trend. Similar results were found for crude oil exposure via skin contact. Exposure to both oil and oil dispersants yielded associations that were appreciably greater in magnitude than for oil alone for all neurological symptoms. Sensitivity analyses excluding responders in the highest environmental heat categories and responders with relevant pre-existing conditions indicated robustness of these results. Stratified analyses indicated possible effect modification by sex, PPE use, and heat exposure. CONCLUSIONS: This study provides evidence of a cross sectional association between crude oil exposures and acute neurological symptoms in a sample of U.S. Coast Guard responders. Additionally, it suggests that exposure to both crude oil and oil dispersant may result in stronger associations and that heat may interact synergistically with oil exposures resulting in more acute neurological symptoms. Future investigations are needed to confirm these findings.

The Deepwater Horizon Oil Spill Coast Guard Cohort study.

OBJECTIVES: Long-term studies of oil spill responders are urgently needed as oil spills continue to occur. To this end, we established the prospective Deepwater Horizon (DWH) Oil Spill Coast Guard Cohort study. METHODS: DWH oil spill responders (n=8696) and non-responders (n=44 823) who were members of the US Coast Guard (20 April-17 December 2010) were included. This cohort uses both prospective, objective health data from military medical encounters and cross-sectional survey data. Here, we describe the cohort, present adjusted prevalence ratios (PRs) estimating cross-sectional associations between crude oil exposure (none, low/medium, high) and acute physical symptoms, and present adjusted relative risks (RRs) based on longitudinal medical encounter data (2010-2012) for responders/non-responders and responders exposed/not exposed to crude oil. RESULTS: Responders and non-responders in this large cohort (n=53 519) have similar characteristics. Crude oil exposure was reported by >50% of responders. We found statistically significant associations for crude oil exposure with coughing (PRhigh=1.78), shortness of breath (PRhigh=2.30), wheezing (PRhigh=2.32), headaches (PRhigh=1.46), light-headedness/dizziness (PRhigh=1.96), skin rash/itching (PRhigh=1.87), diarrhoea (PRhigh=1.76), stomach pain (PRhigh=1.67), nausea/vomiting (PRhigh=1.48) and painful/burning urination (PRhigh=2.89) during deployment. Longitudinal analyses revealed that responders had elevated RRs for dermal conditions (RR=1.09), as did oil-exposed responders for chronic respiratory conditions (RR=1.32), asthma (RR=1.83) and dermal conditions (RR=1.21). CONCLUSIONS: We found positive associations between crude oil exposure and various acute physical symptoms among responders, as well as longer term health effects. This cohort is well positioned to evaluate both short-term and long-term effects of oil spill exposures using both self-reported and clinical health data.