Effects of prenatal polycyclic aromatic hydrocarbons and childhood material hardship on reading achievement in school-age children: A preliminary study

Abstract

BackgroundChildren from socioeconomically disadvantaged backgrounds are at elevated risk for reading problems. They are also likely to live in neighborhoods with high levels of air pollution and to experience material hardship. Despite these risk factors, the links between prenatal chemical exposures, socioeconomic adversities, and reading problems in youth from disadvantaged backgrounds remain understudied. Here we examine associations between prenatal exposure to polycyclic aromatic hydrocarbons (PAH), a common air pollutant, and reading skills, and determine if this relationship is exacerbated by material hardship among Black and/or Latinx children who have been followed as part of a longitudinal urban birth cohort.MethodsMothers and their children, who were participants in a prospective birth cohort followed by the Columbia Center for Children’s Environmental Health, were recruited for the current study. Personal prenatal PAH exposure was measured during the third-trimester of pregnancy using a personal air monitoring backpack. Mothers reported their level of material hardship when their child was age 5 and children completed measures of pseudoword and word reading [Woodcock Johnson III Tests of Achievement (WJ-III) Basic Reading Index] at age 7. We used multiple linear regression to examine the effects of the interaction between prenatal PAH and material hardship on Basic Reading Index, controlling for ethnicity/race, sex, birthweight, presence of a smoker in the home (prenatal), and maternal education (prenatal) (N = 53).ResultsA prenatal PAH × material hardship interaction significantly associated with WJ-III Basic Reading Index scores at age 7 (β = −0.347, t(44) = −2.197, p = 0.033). Exploratory analyses suggested that this effect was driven by untimed pseudoword decoding (WJ-III Word Attack: β = −0.391, t(44) = −2.550, p = 0.014).ConclusionEnvironmental chemical exposures can be particularly toxic during the prenatal period when the fetal brain undergoes rapid development, making it uniquely vulnerable to chemical perturbations. These data highlight the interactive effects of environmental neurotoxicants and unmet basic needs on children’s acquisition of reading skill, specifically phonemic processing. Such findings identify potentially modifiable environmental risk factors implicated in reading problems in children from economically disadvantaged backgrounds.

Differential Susceptibility to Benzo[a]pyrene Exposure during Gestation and Lactation in Mice with Genetic Variations in the Aryl Hydrocarbon Receptor and Cyp1 Genes

“…PAH exposure can have significant impacts on the developing fetus, including decreased head circumference, lower birth weight, lower body mass index, and lower APGAR scores [ 61 ]. Cognitive and behavioral effects persist into school age and adolescence [ 15 , 16 ]. PAH exposure has also been linked to an increase in congenital heart defects [ 62 , 63 , 64 ], and AHR agonists have been repeatedly shown to cause heart malformations in animal models [ 65 , 66 ].…”

“…Other adverse human health outcomes associated with PAH exposure include stunted growth in exposed children [ 8 ], metabolic syndrome [ 9 ], immune suppression [ 10 , 11 ], hypertension in both adults [ 12 ] and children [ 13 ], and cardiovascular disease [ 14 ]. Prospective human studies following pregnant women and their children over time recently demonstrated that prenatal and early-life PAH exposure are associated with numerous adverse outcomes, including cognitive impairments and behavioral problems that persist into adolescence [ 15 , 16 , 17 , 18 , 19 ].…”

The Role of Environmental Chemicals in the Etiology of Learning Difficulties: A Novel Theoretical Framework

“…In a recent study, we investigated the combined effects of prenatal PAH exposure and proximal measures of poverty on children's learning difficulties (Greenwood et al, 2022). Specifically, we examined 8 types of material hardships: living conditions, food, housing, billing, clothing, health care, Medicaid access, and public assistance.…”

“…We found that the prenatal PAH by material hardship interaction term was significantly associated with WJ‐III Basic Reading Index scores at age 7 ( β = −.347, t (44)= − 2.197, p = .033). Exploratory analyses suggested that this effect was driven by untimed pseudoword decoding (WJ‐III Word Attack: β = −.391, t (44)= − 2.550, p = .014) (Greenwood et al, 2022). Our findings suggest compounding effects of prenatal PAH exposure by material hardship that manifest word as reading problems by school‐age, potentially indicating underlying issues with grapheme–phoneme correspondence.…”