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Researchers at the University of Chicago have published a paper linking unconventional natural gas development (UNGD) with a rise in hospitalizations for cardiovascular problems in adults ages 65 and older. The study was published in The Lancet, a premier academic journal, and was supported by the University of Chicago and the Argonne National Laboratories.
There have been claims that living near UNGD is associated with certain negative health effects but few studies have been conducted on the matter. This is largely due, according to the authors, to the lack of data and methods necessary to conduct a robust study. UNGD, also referred to as hydraulic fracturing or ‘fracking’, is the process of extracting natural gas from deep underground rock formations using a vertical-then-horizontal drilling technique.
In their study, researchers at Chicago used a difference-in-differences analysis of Medicare claims data collected from 2002 through 2015 from the state of New York, where UNGD was banned, and Pennsylvania, which experienced a rapid influx of UNGD during that time. Medicare claims in otherwise geographically and demographically similar populations of northcentral Pennsylvania, where gas wells were being drilled and fracked, and southern New York were examined to compare the rate of five specific health outcomes. Specifically, the study looked at acute myocardial infarctions (AMI) and bronchiectasis, chronic obstructive pulmonary disease (COPD), heart failure, ischemic heart disease, and stroke.
The study is unique in that it is one of just two studies to utilize New York’s UNGD ban to act as a control to compare against Pennsylvania. Researchers chose areas that were both geographically and demographically similar and used over a decade of Medicare data in their analysis to account for pre- and post-development periods in Pennsylvania.
Ultimately, the study did not find any statistically significant correlations between UNGD and the incidence rates of COPD or stroke. However, there was a statistically significant rise in cardiovascular diseases, such as AMI (heart attack), heart failure, and ischemic heart disease in Pennsylvania in the years following rapid UNGD in the state. In the years prior to the shale boom, both Pennsylvania’s and New York’s rates of cardiovascular disease diagnoses mirrored each other; this trend continued until the boom in development in Pennsylvania in the early 2010s. From 2010 through 2015, when the bulk of shale development occurred in the Commonwealth, researchers found higher rates of AMI, heart failure, and ischemic heart disease when compared to New York, which continued to grow over time indicating that risks continue to exist after the well has been drilled and is operational.
In 2010, hospitalization rates per 1,000 people for AMI, heart failure, and ischemic heart disease were only slightly elevated when compared to New York. Fast forward to 2015, and the gap widens greatly between the states. In 2015, Pennsylvania had an additional 11.8 per 1,000 Medicare recipients hospitalized for AMI alone compared to New York. The rates also rose for heart failure and ischemic heart disease hospitalizations, with an additional 21.6 and 20.4 hospitalizations per 1,000 people, respectively.
The authors argue that their study directly indicates that UNGD is associated with higher rates of cardiovascular diseases and urge policymakers to consider this information, and potentially affected individuals when making decisions related to UNGD in the Commonwealth.
In a statement discussing the paper, Dr. Prachi Sanghavi, assistant professor of Public Health Sciences at the University of Chicago and senior author of the study, noted natural gas’ importance as a “source of energy in our current infrastructure”, but urges policymakers to conduct a cost-benefit analysis to “determine (if) the benefits of gas extraction outweigh the health effects on local populations”.