Impact of Oil and Gas Drilling Activities on Small-for-Gestational-Age Infants in Texas: A Difference-in-Differences Analysis
Year: 2019
Type: article
Study design: Observational Study
Abstract: S10: Quasi-Experimental Designs in Environmental Epidemiology: Applications to the Health Impacts of Energy Policy Changes, Room 417, Floor 4, August 27, 2019, 1:30 PM - 3:00 PM Background: Although 15% of Texas residents live within 1.6km of an oil or gas drilling site, health outcomes associated with air pollution from this industry remain largely understudied. A key challenge with oil and gas drilling is that large economic changes occur simultaneously with potential environmental exposures. This study quantifies associations among in utero drilling pollution exposures and incidence of small-for-gestational-age (SGA) infants in a difference-in-differences analysis. Methods: We leverage a geocoded population-based retrospective birth cohort in Texas between 1996 and 2009 (n=2.8 million), which corresponds to the rapid increase in drilling activities across the state. Using a difference-in-differences design, we compare SGA among pregnant women who reside within 2,000m of an active drilling site to SGA among pregnant women who reside within the same buffer of a drilling site before it becomes active, and then compare these women to a contemporaneous population of pregnant women that reside 3,000-10,000m away. Within this framework, we use multilevel logistic regression with adjustments for infant demographics, maternal socioeconomic status, and neighborhood contextual characteristics. We present results from a traditional epidemiological regression and the difference-in-differences framework to demonstrate variations in results by approach. Results: We show that the socioeconomic impact of drilling substantially changes regional population characteristics but not local population characteristics, thus the difference-in-difference method is justified. Our results demonstrate increased risk of SGA (OR: 1.06; 95% CI: 1.04, 1.08) among pregnant women who resided within 2,000m of at least one drilling site during pregnancy. These results were attenuated (OR: 1.02; 95% CI: 1.00, 1.05) by the inclusion of county fixed effects to account for potential residual spatial variations. Conclusions: Increased risks of SGA are associated with drilling exposures in Texas. Furthermore, we demonstrated that difference-in-differences designs are needed to isolate effects from the substantial socioeconomic contextual changes associated with drilling activities.
Source: Environmental Epidemiology
Authors: Willis M, Hill E, Kile M, Carozza S, Hystad P
Institutions: Oregon State University, University of Rochester
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,200
OpenAlex ID: W2981326054