A Multi Region Analysis of Shale Drilling Activity and Rates of Sexually Transmitted Infections in the United States

Abstract

Background: Fossil fuel extraction from deep shale rock formations using new drilling technologies such as hydraulic fracturing, has rapidly increased in the Unites States (U.S.) over the past decade. Increases in nonlocal, specialized workers to meet the demands of this complex industry have been suggested to influence rates of sexually transmitted infections (STI) in counties with shale drilling activity; these associations may vary geographically. In this multi-region ecologic analysis, we examine the associations between shale drilling activity and rates of three reportable STI in Colorado, North Dakota, and Texas, states with active shale drilling.Methods: We obtained annual reported rates of chlamydia, gonorrhea, and syphilis from the Centers for Disease Control and Prevention (CDC), number of active shale wells from Enverus (formerly known as DrillingInfo), and sociodemographic covariates from the U.S. Census Bureau. We used multivariable mixed-effects Poisson regression modeling to estimate rate ratios (RR) with 95% confidence intervals (CIs) adjusted for potential confounders and secular trends. The ecological study design allowed us to study health indicators that may follow from industrial changes at policy-relevant geographical scales.Results: In Texas, county-years with high drilling activity had 10% increased rates of chlamydia (RR=1.10; 95% CI=1.04-1.17) and 15% increased rates of gonorrhea (RR=1.15; 95% CI = 1.04-1.28), compared to county-years with no drilling. No statistically significant associations were reported for syphilis or for any STIs in Colorado or North Dakota.Conclusions: Associations between shale drilling and chlamydia and gonorrhea in Texas may reflect increased risk in areas with higher drilling activity and a greater number of major metropolitan areas. This ecologic analysis provides an important assessment of community-level health impacts of the UOG industry. Inter-state differences highlight the need for local epidemiology to prioritize community health policies.