A new study is the first to find a difference between how boys and girls respond to prenatal exposure to the insecticide chlorpyrifos. Researchers at the Columbia Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health found that, at age 7, boys had greater difficulty with working memory, a key component of IQ, than girls with similar exposures.
On the plus side, having nurturing parents improved working memory, especially in boys, although it did not lessen the negative cognitive effects of exposure to the chemical.
Results are published online in the journal Neurotoxicology and Teratology.
In 2011, research led by Virginia Rauh, ScD, Co-Deputy Director of CCCEH, established a connection between prenatal exposure to chlorpyrifos and deficits in working memory and IQ at age 7. Earlier this year, a follow-up study showed evidence in MRI scans that even low to moderate levels of exposure during pregnancy may lead to long-term, potentially irreversible changes in the brain. The latest study, led by Megan Horton, PhD, explored the impact of sex differences and the home environment on these health outcomes.
Dr. Horton and colleagues looked at a subset of 335 mother-child pairs enrolled in the ongoing inner-city study of environmental exposures, including measures of prenatal chlorpyrifos in umbilical cord blood. When the children reached age 3, the researchers measured the home environment using the Home Observation for Measurement of the Environment (HOME) criteria, including two main categories: 1) environmental stimulation, defined as the availability of intellectually stimulating materials in the home and the mother's encouragement of learning; and 2) parental nurturance, defined as attentiveness, displays of physical affection, encouragement of delayed gratification, limit setting, and the ability of the mother to control her negative reactions. The researchers tested IQ at age 7.
While home environment and sex had no moderating effect on IQ deficits related to chlorpyrifos exposure, the researchers uncovered two intriguing findings related to sex differences, albeit of borderline statistical strength: first, that chlorpyrifos exposure had a greater adverse cognitive impact in boys as compared to girls, lowering working memory scores by an average of three points more in boys than girls (96.5 vs. 99.8); and second, that parental nurturing was associated with better working memory, particularly in boys.
"There's something about boys that makes them a little more susceptible to both bad exposures and good exposures," says Dr. Horton. "One possible explanation for the greater sensitivity to chlorpyrifos is that the insecticide acts as an endocrine disruptor to suppress sex-specific hormones. In a study of rats, exposure to the chemical reduced testosterone, which plays a critical role in the development of the male brain."
Going forward, Dr. Horton will look at how sex and the home environment may influence the effects of prenatal exposure to other environmental toxicants, such as those found in air pollution. "I expect this information will be useful in efforts to develop new interventions to protect children from the potentially negative consequences of early exposure to harmful chemicals," says Dr. Horton.
The insecticide chlorpyrifos was widely used in homes until 2001 when the U.S. Environmental Protection Agency restricted indoor residential use, permitting continued commercial and agricultural applications. Since that time, a drop in residential levels of chlorpyrifos has been documented by Robin Whyatt, DrPH, Co-Deputy Director of CCCEH. The chemical continues to be present in the environment through its widespread use in agriculture (food and feed crops), wood treatments, and public spaces such as golf courses, some parks, and highway medians. People near these sources can be exposed by inhaling the chemical, which drifts on the wind. Low-level exposure can also occur by eating fruits and vegetables that have been sprayed with chlorpyrifos. Although the chemical is degraded rapidly by water and sunlight outdoors, it has been detected by the Columbia researchers in many urban residences several years after the ban went into effect. Many developing countries continue to use chlorpyrifos in the home setting.
The study was supported by the National Institute of Environmental Health Sciences Grants 5P01ES09600, P50ES015905, and 5R01ES08977, as well as pilot funding through ES009089; EPA STAR Grants RD834509, RD832141, and R827027; National Institute of Mental Health Grants MH068318 and K02-74677; and the John and Wendy Neu Family Foundation.
Additional co-authors included Linda G. Kahn, Frederica P. Perera, and Virginia Rauh, Mailman School; and Dana BoydBarr, Emory University.
Timothy S. Paul | EurekAlert!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy