Reference
Jiang H, Justice L, Purtell K, Bates R. Exposure to environmental toxicants and early language development for children reared in low-income households. Clin Pediatr (Phila). 2020;59(6):557-565.
Study Objective
To assess the extent to which children’s early exposure to toxicants may be associated with lags in early language development for children born into low-income homes.
Design
A prospective, observational study that used data from the Kids in Columbus Study—a 5-year birth cohort study of children born into low-income families.
Participants
The participants were mothers who were pregnant or had children under 3 months of age at the time of enrollment; were aged 18 or older; and were able to speak English at a conversational level. Of the participants, 80% reported a family income of less than $30,000 per year. Children who were born prematurely or diagnosed with a severe medical condition were excluded from the study. Enrolled in the study were 322 mother-child dyads; however, the study eventually analyzed data from 190 families once participant attrition and missing data were accounted for.
Study Parameters Assessed
This study examined mothers’ exposure to environmental toxicants during and shortly after pregnancy, as well as at 1.5 years postpartum. The investigators collected data on child development at 1 and 2 years.
Primary Outcome Measures
The investigators gathered information via home visits to mothers at 5-month intervals starting at 2 months gestation to 4 months postpartum and continuing until the child was aged 2 years. The investigators asked the mothers questions about exposures to certain environmental toxicants. The investigators also administered the Bayley Scales of Infant and Toddler Development 3rd Edition to the children.
At recruitment and 1.5 years postpartum, mothers answered a series of questions regarding their exposure to toxicants. At both time points, the investigators asked the mothers the following: (1) whether there was mold in their current residence; (2) whether they used pesticides (at home, on pets, or in lawns/gardens) during pregnancy or within the past year; and (3) whether they regularly (at least weekly) used any of the items from a list of potential household chemicals (glass cleaner, oven cleaner, floor cleaner, drain cleaner, toilet cleaner, shoe polish, solvents, paint strippers, sealant, and bug spray) during pregnancy or within the last year.
In addition, at enrollment the investigators asked the mothers whether they had lived within 0.5 miles of any of the following 8 locations in the past 5 years: landfills or dumpsites, closed and empty factories, heavy traffic, vehicle idling areas, farms, industrial plants, polluted lakes or streams, and hydro towers.
The investigators assessed children’s language development at 1 and 2 years using the Bayley Scales of Infant and Toddler Development 3rd Edition. They compiled a scaled score looking at the subsets of development and cognition. The investigators then examined the relationship to toxicant exposure and language development scores.
Key Findings
This study suggests that toxicant use inside the home, specifically the use of household cleaners within the first and second years of life, has a significant correlation with decreased scores in children’s early language and cognitive development. Neighborhood pollution, mold exposure, and pesticides were not as impactful.
When looking at early language development, exposure to toxicants during pregnancy accounted for a 1%–1.6% variance in language skills, while exposure to toxicants after birth correlated with a 6.7% variance in language outcome at 2 years. For cognitive outcomes, toxicant exposure during pregnancy related to a 1.8% variance at 1 year of age and a 3.5% variance at 2 years.
Specifically, the use of household cleaners seemed to be the most impactful. With household-cleaner use at more than 1 standard deviation above the mean, children were found to score at 0.21 standard deviations lower in language and 0.24 standard deviations lower in cognition.
Practice Implications
First, African Americans represent approximately 28.5% of the population of Columbus, Ohio, and yet represented 41% of the participants in this study. One cannot discuss environmental toxicant exposure without also pointing out the structural racism that results in black and brown populations being overexposed to environmental toxicants. Black and brown people are disproportionately exposed to environmental pollutants resulting from residential segregation, unequal access to economic opportunity, and the concentration of factories, highways, landfills, etc. in nonwhite neighborhoods. These populations bear the brunt of our country’s toxic exposure, and this contributes further to a legacy of health and economic disparities that stem from policies influenced by racial injustice.
Additionally, the chronic stress of living with racism may increase vulnerability to negative health outcomes from environmental exposure.1,2
It is imperative that all practitioners of integrative medicine not frame environmental toxicant exposure as solely a matter of personal choice. Instead, practitioners should understand the widespread impact of systemic racism on health outcomes. We must all educate ourselves on topics of environmental justice and advocate within our communities for the end of this particular manifestation of injustice. More information and resources on how to advocate for these changes are available from Black Lives Matter and Integrative Medicine for the Underserved.
Specifically, the use of household cleaners seemed to be the most impactful. With household-cleaner use at more than 1 standard deviation above the mean, children were found to score at 0.21 standard deviations lower in language and 0.24 standard deviations lower in cognition.
Moving on to the findings of this particular study, as this is a correlational study, we are left with many questions regarding the mechanisms by which toxicant exposures impact language development and cognition. However, as we await further research, the take-home message seems clear. Educate pregnant women and parents about the impact of using toxic cleaning agents in the home. There are many low-cost and safe alternatives to toxic cleaning products, such as vinegar, baking soda, and castille soap.
The American Academy of Pediatrics (AAP) has a relevant position on this topic.3 In 2012, the AAP released a policy statement on pesticide exposure in children, warning of concerns with both acute poisoning and the impact of chronic exposure on long-term development.
While the study reviewed here didn’t show an impact of pesticide exposure specifically correlating with decreased language development or cognition, it did show that 20% of households at 1 year and 30% of households at 2 years were using pesticides. This illustrates why education regarding pesticides is still critical. This study is an important addition to the growing body of literature on the negative influence of toxicant exposure on children. It gives specific action items that are easily applied in practice: survey patients about their exposure and offer them education on alternatives. This is a simple intervention we can offer, while we also work to dismantle the systems that result in an unequal distribution of environmental risks.
