Associations between airborne crude oil chemicals and symptom-based asthma

Environ Int. 2022 Sep:167:107433. doi: 10.1016/j.envint.2022.107433. Epub 2022 Jul 27.

Abstract

Rationale: The 2010 Deepwater Horizon (DWH) oil spill response and cleanup (OSRC) workers were exposed to airborne total hydrocarbons (THC), benzene, toluene, ethylbenzene, o-, m-, and p-xylenes and n-hexane (BTEX-H) from crude oil and PM2.5 from burning/flaring oil and natural gas. Little is known about asthma risk among oil spill cleanup workers.

Objectives: We assessed the relationship between asthma and several oil spill-related exposures including job classes, THC, individual BTEX-H chemicals, the BTEX-H mixture, and PM2.5 using data from the Gulf Long-Term Follow-up (GuLF) Study, a prospective cohort of 24,937 cleanup workers and 7,671 nonworkers following the DWH disaster.

Methods: Our analysis largely focused on the 19,018 workers without asthma before the spill who had complete exposure, outcome, and covariate information. We defined incident asthma 1-3 years following exposure using both self-reported wheeze and self-reported physician diagnosis of asthma. THC and BTEX-H were assigned to participants based on measurement data and work histories, while PM2.5 used modeled estimates. We used modified Poisson regression to estimate risk ratios (RR) and 95% confidence intervals (CIs) for associations between spill-related exposures and asthma and a quantile-based g-computation approach to explore the joint effect of the BTEX-H mixture on asthma risk.

Results: OSRC workers had greater asthma risk than nonworkers (RR: 1.60, 95% CI: 1.38, 1.85). Higher estimated THC exposure levels were associated with increased risk in an exposure-dependent manner (linear trend test p < 0.0001). Asthma risk also increased with increasing exposure to individual BTEX-H chemicals and the chemical mixture: A simultaneous quartile increase in the BTEX-H mixture was associated with an increased asthma risk of 1.45 (95% CI: 1.35,1.55). With fewer cases, associations were less apparent for physician-diagnosed asthma alone.

Conclusions: THC and BTEX-H were associated with increased asthma risk defined using wheeze symptoms as well as a physician diagnosis.

Keywords: Asthma; BTEX-H; Mixtures; Oil spills; Total hydrocarbons; Volatile organic compounds.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Asthma* / epidemiology
  • Benzene / analysis
  • Humans
  • Hydrocarbons / analysis
  • Particulate Matter / adverse effects
  • Particulate Matter / analysis
  • Petroleum Pollution* / adverse effects
  • Petroleum Pollution* / analysis
  • Petroleum* / adverse effects
  • Prospective Studies

Substances

  • Benzene
  • Hydrocarbons
  • Particulate Matter
  • Petroleum