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Childhood Cancer Incidence in Pennsylvania Counties in Relation to Living in Counties With Hydraulic Fracturing Sites

Fryzek, Jon PhD; Pastula, Susan MPH; Jiang, Xiaohui MPH; Garabrant, David H. MD, MPH

Journal of Occupational and Environmental Medicine: July 2013 - Volume 55 - Issue 7 - p 796–801
doi: 10.1097/JOM.0b013e318289ee02
Original Articles

Objective: Evaluate whether childhood cancer incidence is associated with counties with hydraulic fracturing (HF).

Methods: We compared cancer incidence in children in Pennsylvania counties before and after HF drilling began, using standardized incidence ratios (SIRs) and 95% confidence intervals (CIs).

Results: The total number of cancers observed was close to expected both before drilling began (SIR = 0.94; 95% CI, 0.90 to 0.99) and after drilling (SIR = 1.02; 95% CI, 0.98 to 1.07) for counties with oil and natural gas wells. Analyses for childhood leukemia were also unremarkable (SIR for leukemia before drilling = 0.97 [95% CI, 0.88 to 1.06]; SIR for leukemia after drilling = 1.01 [95% CI, 0.92 to 1.11]). A slightly elevated SIR was found for central nervous system tumors after drilling (SIR = 1.13; 95% CI, 1.02 to 1.25). This was because of a slight excess in those counties with the fewest number of wells.

Conclusions: This study offers comfort concerning health effects of HF on childhood cancers.

From the EpidStat Institute (Drs Fryzek and Garabrant) and David Garabrant PLLC (Ms Pastula and Ms Jiang), Ann Arbor, Mich.

Address Correspondence to: David H. Garabrant, MD, MPH, EpidStat Institute, 2100 Commonwealth Blvd No. 203, Ann Arbor, MI 43105 (

This research was supported by a grant from America's Natural Gas Alliance.

The authors declare no conflict of interest.

Copyright © 2013 by the American College of Occupational and Environmental Medicine