Study examines relationship between mountaintop mining and birth defects

MORGANTOWN, W.Va. – A new study co-authored by researchers at West Virginia University found significantly higher prevalence rates for birth defects in mountaintop mining areas compared to other mining areas and non-mining areas.

The team studied more than 1.8 million birth records in West Virginia and surrounding states in central Appalachia.  They compared the prevalence of birth defects in mountaintop coal mining areas compared with other coal mining areas and with non-mining areas for two periods of time: 1996-1999 and 2000-2003.

“We found that birth defects were significantly higher in mountaintop mining areas versus non-mining areas for six of seven types of defects: circulatory/respiratory, central nervous system, musculoskeletal, gastrointestinal, urogenital and ‘other,’” Michael Hendryx, Ph.D., co-author of the study in the WVU Department of Community Medicine, said.

“Overall, the prevalence rate for any defect was significant in both periods but was higher in the more recent period. In the earlier period the rate of birth defects was 13 percent higher in mountaintop mining areas and increased to 42 percent higher in the later period.”

Researchers used secondary data to study all live birth outcomes for the years 1996 through 2003. They determined the mother’s residence relative to county mining type (mountaintop mining, other mining, no mining) and controlled for birth-defect risks including mother’s age, race/ethnic origin, education, smoking and drinking during pregnancy, diabetes, metro/non-metro location, infant gender and low prenatal care.

Dr. Hendryx added that mountaintop mining in one county may contribute to birth-defect prevalence rates in surrounding counties.

“Elevated birth defect rates are partly a function of socioeconomic disadvantage but remain elevated after controlling for those risks, suggesting that environmental influences in mountaintop mining areas may be contributing factors to elevated birth defect rates,” he said.

“A growing body of studies have found significant associations between coal-mining areas and a variety of chronic disease problems for adults, after controlling for other disease risk factors. Research related to infants has found that mothers residing in coal mining areas are more likely to have a low birth weight infant. This study extends that research, showing that mountaintop mining areas are associated with elevated levels of birth defect prevalence rates."

The study was led by Melissa Ahern, a health economist at Washington State University. In addition to Hendryx, WVU co-authors of the study include Alan Ducatman, M.D., and Keith Zullig, Ph.D., of the Department of Community Medicine and Jamison Conley and Evan Fedorko of the Department of Geology and Geography.

It was published online and will appear in an upcoming issue of “Environmental Research: A Multidisciplinary Journal of Environmental Sciences, Ecology and Public Health.” It can be viewed at www.sciencedirect.com/science/article/pii/S0013935111001484.