Author Interviews, Cognitive Issues, Environmental Risks, Pediatrics, Toxin Research / 12.04.2019
Lead in Topsoil Linked to Cognitive Difficulties in 5 Year Old Boys
MedicalResearch.com Interview with:
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Dr. Severnini[/caption]
Edson R. Severnini PhD
Assistant Professor Of Economics And Public Policy
Carnegie Mellon University
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Although lead has been banned from gasoline, paint, and other substances in the United States and many other countries around the world, the legacy of lead use is a critical environmental and public health issue. Surface soil contamination, in particular, has been long recognized as an important pathway of human lead exposure, and is now a worldwide health concern.
This study estimates the causal effects of exposure to lead in topsoil on cognitive ability among 5-year-old children. We draw on individual level data from the 2000 U.S. Census, and USGS data on lead in topsoil covering a broad set of counties across the United States.
We find that higher lead in topsoil increases considerably the probability of 5-year-old boys experiencing cognitive difficulties such as learning, remembering, concentrating, or making decisions. Living in counties with topsoil lead concentration above the national median roughly doubles the probability of 5-year-old boys having cognitive difficulties. This harmful effect does not seem to extend to 5-year-old girls, potentially due to the natural protection of estrogen.
Dr. Severnini[/caption]
Edson R. Severnini PhD
Assistant Professor Of Economics And Public Policy
Carnegie Mellon University
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Although lead has been banned from gasoline, paint, and other substances in the United States and many other countries around the world, the legacy of lead use is a critical environmental and public health issue. Surface soil contamination, in particular, has been long recognized as an important pathway of human lead exposure, and is now a worldwide health concern.
This study estimates the causal effects of exposure to lead in topsoil on cognitive ability among 5-year-old children. We draw on individual level data from the 2000 U.S. Census, and USGS data on lead in topsoil covering a broad set of counties across the United States.
We find that higher lead in topsoil increases considerably the probability of 5-year-old boys experiencing cognitive difficulties such as learning, remembering, concentrating, or making decisions. Living in counties with topsoil lead concentration above the national median roughly doubles the probability of 5-year-old boys having cognitive difficulties. This harmful effect does not seem to extend to 5-year-old girls, potentially due to the natural protection of estrogen.
Dr. McLaughlin[/caption]
Ryan J. McLaughlin, PhD
Assistant Professor
Department of Integrative Physiology & Neuroscience
College of Veterinary Medicine
Washington State University
Pullman, WA 99164-7620
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The use of cannabis during pregnancy is a growing health concern, yet the long-term cognitive ramifications for developing offspring remain largely unknown. Human studies exploring the long-term effects of maternal cannabis use have been sparse for several reasons, including the length and cost of such studies, as well as the fact that experimentally assigning mothers to smoke cannabis during pregnancy is obviously ethically impractical. Animal models of maternal cannabis use have been advantageous in this respect, but they have been limited by the drugs used (synthetic cannabinoids vs. THC vs. cannabis plant) and the way that they are administered. In our study, we used a more translationally relevant animal model of maternal cannabis use that exposes pregnant rat dams to whole plant cannabis extracts using the intra-pulmonary route of administration that is most common to human users. Our preliminary data indicate that twice-daily exposure to a high-dose cannabis extract during pregnancy may produce deficits in cognitive flexibility in adult rat offspring. Importantly, these rats did not experience general learning deficits, as they performed comparably to non-exposed offspring when required to follow a cue in their environment that dictate reinforcer delivery. Instead, deficits were observed only when rats were required to disregard this previous cue-based strategy and adopt a new egocentric spatial strategy in order to continue receiving the sugar reinforcers.














