Congential Heart Defects and Intensity of Upstream Oil and Natural Gas Activities in Early Pregnancy

摘要

Our previous study indicated that mothers of infants with congenital heart defects are more likely to live in dense areas of upstream oil and natural gas (O&G) activity. The potential for exposure misclassification was a major limitation of our previous study because it lacked sufficient spatial and temporal granularity to determine the variability in maternal exposures immediately before conception and during early pregnancy or between the intensity of upstream O&G activities. To address this limitation, we applied our newly developed spatial-temporal industrial activity model in a nested case-control study, of 3,324 Colorado singleton-live births between 2005 and 2011 to mothers living in a county where at least 20 O&G well started per 10,000 births between 2004 and 2011. This spatial-temporal activity model allowed us to estimate intensities of specific upstream O&G activities in the three months before conception through the first two months of gestation, the critical development window for the developing heart. Our cases were 65, 179, 38, and 187 children born with a conotruncal, tricuspid valve, pulmonary artery, or aortic valve defect, respectively. Our 2,860 controls were children without a birth defect. We found that, after adjusting for the infant's sex and mother's age, parity, ethnicity, smoking, and proximity to other air pollution sources, mothers of children born with a conotruncal, pulmonary artery, or aortic valve defect were more likely to live in areas of dense upstream O&G activity than in areas with no activity. Our results contribute to the evidence base of the potential for adverse health effects in populations living in close proximity to upstream O&G activities and provide justification for strategies to prevent or reduce exposures and improve health in these populations.