Occupational
Association of oil spill related total hydrocarbon exposure with blood pressure and hypertension in the Gulf Long-term Follow-up Study Opal P. Patel* Opal Patel Jessie K. Edwards Anna M. Kucharska-Newton Eric A. Whitsel Braxton Jackson Lawrence S. Engel Dale P. Sandler
Background: Volatile organic compound and total hydrocarbon (THC) exposures are common following oil spills and are associated with risk of cardiovascular disease. In a study among Gulf Long-term Follow-up (GuLF) Study participants, THC exposure was associated with elevated risk of hypertension. However, that study did not evaluate individual constituents such as benzene, toluene, ethyl-benzene, xylene, and n-hexane (BTEX-H). Here we examine associations of BTEX-H exposures with blood pressure (BP) and hypertension.
Methods: Subjects comprised 6,813 Deepwater Horizon (DWH) oil spill workers who completed a GuLF Study home visit (2011 to 2013). A job-exposure matrix linked air measurement data to detailed participant DWH work histories to estimate cumulative exposures during oil spill response and clean-up work. Exposures to BTEX-H were assessed as quartiles, with the first quartile as the referent. Trained examiners took BP measurements during the home visit. Incident hypertension was defined as having elevated BP or newly diagnosed hypertension with new onset antihypertensive medication use since the spill. We estimated exposure effects on continuous BP using multivariable linear regression. We calculated prevalence ratios (PR) and 95% CIs for hypertension using modified Poisson regression. To assess the joint effect of the BTEX-H mixture, we used quantile g-computation.
Results: Among these participants, 79.3% were male, 52.9% were non-Hispanic white, and 34.7% were non-Hispanic black. Increasing quartiles of individual BTEX-H exposures exhibited exposure-response relationships for diastolic BP. The BTEX-H mixture was positively associated with both systolic (β=0.49; 95% CI: 0.15, 0.84) and diastolic BP (β=0.46; 95% CI: 0.21, 0.70). We observed non-monotonic increases in hypertension risk with increasing exposure to benzene, toluene, and hexane.
Conclusion: Higher exposures to BTEX-H were associated with modest elevations in hypertension risk and blood pressure.