Exposure to common air pollutants during pregnancy may predispose children to problems regulating their thoughts, emotions, and behaviors later on, according to a new study led by researchers at the Columbia Center for Children’s Environmental Health within Columbia University’s Mailman School of Public Health and New York State Psychiatric Institute. The new study is the first of its kind to examine the effects of early life exposure to a common air pollutant known as PAH (polycyclic aromatic hydrocarbons) on self-regulating behaviors and social competency that incorporates multiple assessment points across childhood. Children with poor self-regulation skills have difficulty managing disruptive thoughts, emotions, and impulses; poor social competency limits their ability to get along with others. The findings appear in the Journal of Child Psychology and Psychiatry.

PAH are ubiquitous in the environment from emissions from motor vehicles; oil, and coal burning for home heating and power generation; tobacco smoke; and other combustion sources. (More on PAH and ways to limit exposure can be found on the CCCEH website.) Prenatal exposure to PAH has been associated with ADHD; symptoms of anxiety, depression and inattention; and also behavioral disorders, which are all thought to be related to deficits in self-regulation.

Lead investigator Amy Margolis, assistant professor of medical psychology in the Department of Psychiatry at Columbia University Medical Center and New York State Psychiatric Institute, and colleagues analyzed maternal blood samples and child tests results from 462 mother-child pairs, a subset of CCCEH’s ongoing urban birth cohort study in New York City, from pregnancy through early childhood. Maternal exposure to PAH was determined by presence of DNA-PAH adducts in a maternal blood sample.

Children were tested with the Child Behavior Checklist at ages 3-5, 7, 9, and 11. Scores obtained from the CBCL were used to create a composite score for the Deficient Emotional Self-Regulation Scale (DESR), and higher scores on the DESR indicated reduced capabilities to self-regulate. Investigators found that children whose mothers had higher exposure to PAH in pregnancy had significantly worse scores on the DESR at ages 9 and 11 than children whose mothers had lower exposure to PAH in pregnancy. Over time, low-exposure children followed a typical developmental pattern and improved in self-regulatory function, but the high-exposed children did not, underscoring the long-term effect of early-life exposure to PAH. Additionally, researchers found that DESR score had a mediating effect on tests of social competence, indicating that self-regulation is an important factor in developing social competence.

The evidence that prenatal exposure to PAH leads to long-term effects on self-regulatory capacities during early and middle childhood suggests that PAH exposure may be an important underlying and contributing factor to the genesis of a range of childhood mental health problems. In terms of a potential mechanism, researchers suggest that prenatal exposure to PAH damages neural circuits that direct motor, attentional, and emotional responses. Further deficits in self-regulation may predispose children to becoming engaged in high-risk adolescent behaviors.

“This study indicates that prenatal exposure to air pollution impacts development of self-regulation and as such may underlie the development of many childhood psychopathologies that derive from deficits in self-regulation, such as ADHD, OCD, substance use disorders, and eating disorders,” says Margolis.

About this pollution and psychology research

Funding: Support for the study was provided by the National Institute of Environmental Health Sciences (NIEHS) and the U.S. Environmental Protection Agency (US EPA): NIEHS/EPA P01ES09600/R82702701, NIEHS/EPA P01ES09600/RD83214101, NIEHS/EPA P01ES09600/RD83450901, NIEHS R01ES08977, NIEHS R01ES015579; and the National Institute on Drug Abuse (NIDA): NIDA R01DA027100, NIDA R01ES015282. The study was also made possible in part by the New York Community Trust, the Blanchette Hooker Rockefeller Foundations, and the John and Wendy Neu Foundation. The authors declare no conflicts.

Co-authors include Virginia Rauh, Julie Herbstman, Frederica Perera, Deliang Tang, Ya Wang, Shuang Wang, and Valerie Thomas from Columbia’s Mailman School; Katie Davis of Columbia University Medical Center; and Bradley Peterson from the University of Southern California.

Source: Columbia University’s Mailman School of Public Health

Image Source: The image is in the public domain.

Original Research: Abstract for “Longitudinal effects of prenatal exposure to air pollutants on self-regulatory capacities and social competence” by Amy E. Margolis, Julie B. Herbstman, Katie S. Davis, Valerie K. Thomas, Deliang Tang, Ya Wang5, Shuang Wang, Frederica P. Perera, Bradley S. Peterson and Virginia A. Rauh in Journal of Child Psychology and Psychiatry. Published online March 17 2016 doi:10.1111/jcpp.12548

Abstract

Longitudinal effects of prenatal exposure to air pollutants on self-regulatory capacities and social competence

Background

We evaluated the influence of prenatal exposure to widespread urban air pollutants on the development of self-regulation and social competence in a longitudinal prospective cohort of children born to nonsmoking minority women in New York City.

Methods

Air pollutant exposure was estimated categorically by level of polycyclic aromatic hydrocarbon (PAH)-DNA adducts in maternal blood collected at delivery, providing a biomarker of maternal exposure to PAH over a 2- to 3-month period. Deficient emotional self-regulation (DESR) was defined as moderate elevations on three specific scales of the child behavior checklist (anxious/depressed, aggressive behavior, and attention problems). We used generalized estimating equations to assess the influence of prenatal exposure to PAH on DESR in children at 3–5, 7, 9, and 11 years of age, adjusted for gender and race/ethnicity. Next, we assessed the association of prenatal exposure to PAH with social competence, as measured by the social responsiveness scale (SRS), the association of impaired self-regulation with social competence, and whether impairment in self-regulation mediated the association of prenatal exposure to PAH with social competence.

Results

We detected a significant interaction (at p = .05) of exposure with time, in which the developmental trajectory of self-regulatory capacity was delayed in the exposed children. Multiple linear regression revealed a positive association between presence of PAH-DNA adducts and problems with social competence (p < .04), level of dysregulation and problems with social competence (p < .0001), and evidence that self-regulation mediates the association of prenatal exposure to PAH with social competence (p < .0007).

Conclusions

These data suggest that prenatal exposure to PAH produces long-lasting effects on self-regulatory capacities across early and middle childhood, and that these deficits point to emerging social problems with real-world consequences for high-risk adolescent behaviors in this minority urban cohort.

“Longitudinal effects of prenatal exposure to air pollutants on self-regulatory capacities and social competence” by Amy E. Margolis, Julie B. Herbstman, Katie S. Davis, Valerie K. Thomas, Deliang Tang, Ya Wang5, Shuang Wang, Frederica P. Perera, Bradley S. Peterson and Virginia A. Rauh in Journal of Child Psychology and Psychiatry. Published online March 17 2016 doi:10.1111/jcpp.12548

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