Prenatal Exposure to Household Chemicals Hurts Kids' Cognition

Liam Davenport

February 02, 2016

Exposure to common household chemicals such as those found in nonstick cooking pans, upholstery, carpet pads, and electronics during pregnancy may lead to poorer cognitive and behavioral development during childhood, new research shows.

In an analysis of more than 250 mother-child pairs, maternal exposure to polybrominated diphenyl ethers (PBDEs) and perfluoroalkyl substances (PFASs) was associated with impairments in executive function in children aged 5 and 8 years.

"These findings suggest that concentrations of maternal serum PBDEs and PFASs during pregnancy may be associated with poorer executive function in school-age children," the investigators, with first author Ann Vuong, DrPH, a postdoctoral fellow in the Department of Environmental Health at the University of Cincinnati, in Ohio, write.

"Given that the persistence of PBDEs and PFASs has resulted in detectable serum concentrations worldwide, the observed deficits in executive function may have a large impact at the population level," they add.

The study was published online January 28 in Environmental Research.

Worse Cognition, Executive Function

For the study, the investigators examined data from the prospective birth cohort Health Outcomes and Measures of the Environment Study.

They focused on 256 mother-child pairs, in whom maternal serum PDBE and PFAS levels were measured at 16±3 weeks of gestation. The parent-rated Behavior Rating Inventory of Executive Function (BRIEF) was administered to the children at ages 5 and 8 years; higher scores indicated greater impairment.

They found that higher concentrations of PBDEs were associated with mothers who were nonwhite, less educated, had lower income, were unmarried or living alone, or who had lower scores on the Home Observation for Measurement of the Environment.

Higher levels of the PFASs perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were seen in women who were non-Hispanic white, who had higher income, or who were minimally/mildly depressed.

Using linear mixed models and generalized estimations, the team found that 10-fold increases in levels of the PBDE BDE-153 were associated with having poorer behavior regulation.

Increased BDE-153 levels were also associated with an increased likelihood of having a behavior regulation or global executive functioning score of 60 points or higher on the BRIEF (respective odds ratios, 3.92 and 2.34).

In-unit increases in PFOS levels were associated with worse behavior regulation, poorer metacognition, and poorer global executive functioning. No link was found between PFOA levels and executive function.

Ongoing Risk

Dr Vuong told Medscape Medical News that although the majority of PBDEs and PFASs have been phased out of products, there is an ongoing risk of exposure.

"It's in the environment, and probably it's that people have already purchased products within their homes, and everyone has [PBDEs] in their bodies. So the only way to reduce the body burden or exposure is through cleaning methods," she said.

For PBDEs, it is recommended that people regularly use a high-efficiency particulate air (HEPA) filter in their vacuum and that they wipe down surfaces and regularly wash their hands.

"For PFASs, it's recommended that you try not to, or limit your use of, microwaved fast food packaging, as well as trying not to use deteriorated pans with nonstick coatings," Dr Vuong added.

Although reducing exposure to substances with known neurodevelopmental and cognitive risks is important, Dr Vuong emphasized that the chemicals have been replaced by novel compounds, some of which may carry their own risks.

She observed: "The thing is that they are not regulated, and no one's testing them until after the exposure is high and they notice there may be some effects or some associations.

"I think it's difficult with the way regulation is going to know before you use it what will happen, because you can't test these chemicals on people."

Although Dr Vuong believes that changes are needed to the current regulatory system, she concedes that she is "not sure exactly how we would go about it or how feasible it is for people on the other end to look at it.

"From my public health standpoint, I'd prefer to examine these chemicals thoroughly to see if there is an issue before putting them into products that we're always exposed to or being exposed to on a daily basis," she said.

"From the other people's standpoint, I'm not sure [it's possible], because that's not how they feel. They're probably more into, I guess, convenience or trying to better whatever products that they're producing," Dr Vuong added.

Consistent Findings

Commenting on the findings for Medscape Medical News, Sharon Sagiv, PhD, MPH, Division of Epidemiology, University of California, Berkeley, School of Public Health, said "it's a good cohort, with good investigators" and that the results are "pretty interesting and compelling."

She added that the findings are consistent with those from her own group, published last year, that showed a similar link between PBDEs and executive function.

Dr Sagiv also agreed with Dr Vuong that it is important to test the chemicals being used to replace PBDEs and PFASs, because "we don't know their long-lasting effects yet.

"For many of these chemicals, we just assume they're safe until they're not safe, and maybe we should be testing to see whether they're safe before we assume that they are. I think that's a system problem," she added.

Typically, she noted, studies of the effects of chemicals take a very long time to conduct. "It's unfortunate that it takes so many years to know which chemicals are harmful or are potentially harmful," she noted.

Dr Sagiv concluded by pointing out that executive function impairments are "very important."

"Impairments in executive function can be quite impacting on an individual, so I would say that this is a pretty important outcome to be looking at," she said.

"I'm glad to see that other studies are also focusing on this endpoint."

Environ Res. Published online January 28, 2016. Abstract


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