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.