PM2.5 threshold exceedances during the prenatal period and risk of intellectual disability.

BACKGROUND: Research demonstrates that chronic exposure to fine particulates (PM2.5) increases risks of neurodevelopmental conditions, such as intellectual disability (ID). Few studies have examined neurodevelopmental health impacts of pollution spikes exceeding 24-h (24-h) PM2.5 guidelines, despite relevance to the regulatory landscape. The current potential for regulatory changes to 24-h PM2.5 standards in the United States makes research on exceedances relevant. OBJECTIVE: To examine associations between 24-h PM2.5 exceedances and the risk of ID. METHODS: We conducted a retrospective case-control study of a sample of children in Utah, USA. We used generalized estimating equations to predict odds of ID based on the number of 24-h PM2.5 exceedance days during the preconception period and three trimesters of pregnancy. Exceedance days are defined as per current World Health Organization (WHO) [≥15 µg/m3] and current US Environmental Protection Agency (EPA) [≥35 µg/m3] 24-h guidelines. RESULTS: PM2.5 exceedances are associated with ID risk during the preconception and first trimester periods and not the second and third trimesters. During the preconception period, each day exceeding 15 µg/m3 or 35 µg/m3 was associated with a 1.023 (CI: 1.011-1.040) or 1.042 (CI: 1.026-1.059, p < 0.001) increase in odds of ID, respectively. During the first trimester, each day exceeding 15 µg/m3 or 35 µg/m3 was associated with a 1.032 (CI: 1.017-1.047) or 1.059 (CI: 1.030-1.088) increase in odds of ID, respectively. IMPACT STATEMENT: Potential regulatory movement on the US 24-h PM2.5 standard makes research that explicitly studies exceedances highly relevant. Yet few studies examine health effects of exceeding 24-h guidelines for any air pollutants. This study fills important gaps in the literature by examining associations between odds of intellectual disability and the count of days exceeding current 24-h PM2.5 guidelines, as established by the World Health Organization and US Environmental Protection Agency, during the prenatal period. We find that exceedances of both sets of guidelines, during the preconception and first trimester periods, are associated with ID risk.

Trimester-specific ambient PM2.5 exposures and risk of intellectual disability in Utah.

Prenatal fine particulate matter (PM2.5) exposure is an understudied risk factor for neurodevelopmental outcomes, including intellectual disability (ID). Associations among prenatal exposures and neurodevelopmental outcomes may vary depending on the timing of exposure. Limited numbers of studies examining PM2.5 and neurodevelopmental outcomes have considered exposures occurring during the preconception period. To address these gaps, we conducted a case-control study of children born in Utah between 2002 and 2008 (n = 1032). Cases were identified using methods developed by the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network and matched with controls on birth year, sex, and birth county. We estimated the daily average PM2.5 concentration during a period spanning 12 weeks before the estimated conception date, as well as during each of the three trimesters at the maternal residential address listed on the child's birth certificate. In a multivariable model, the third (OR: 2.119, CI: 1.123-3.998, p = .021) and fourth (OR: 2.631, CI: 1.750-3.956, p < .001) quartiles for preconception average PM2.5 demonstrated significantly increased risk of ID relative to the first quartile. Second quartile preconception exposure was also associated with increased risk, though it did not reach significance (OR: 1.385, CI: 0.979-1.959, p = .07). The fourth quartile of first trimester average PM2.5 was positive and significant (OR: 2.278, CI: 1.522-3.411, p < .001); the third quartile was positive, but not significant (OR: 1.159, CI: 0.870-1.544, p = .312). Quartiles of second and third trimester were not associated with higher risk of ID. These findings from Utah, which were robust to a variety of sensitivity analyses, provide initial evidence that preconception and prenatal PM2.5 exposure may be associated with ID. Future studies are needed across other geographic locations and populations.

Associations between estimates of perinatal industrial pollution exposures and intellectual disability in Utah children.

While heavy metals exposure is associated with intellectual disability (ID), little is known about associations between industrial pollution and ID. The objective of this analysis is to assess associations between estimated perinatal industrial pollution exposures from the US Environmental Protection Agency's Risk Screening Environmental Indicators Microdata and children's ID risk. We conducted a case-control study of children born in Utah from 2000 to 2008 (n = 1679). Cases were identified through the Center for Disease Control's Autism and Developmental Disabilities Monitoring Network's Utah site and matched with controls based on birth year, sex, and birth county. We used multivariable generalized estimating equations to examine associations between estimated perinatal industrial pollution exposures and ID risk. The fourth quartile of industrial pollution exposure was associated with increased odds of ID relative to the first (Odds Ratio [OR]: 1.73, 95% Confidence Interval [CI]: 1.23-2.44) and second (OR: 1.67, CI: 1.19-2.35) quartiles. Similarly, the third quartile was associated with increased odds of ID relative to the first (OR: 1.47, CI: 1.06-2.03) and second (OR: 1.41, CI: 1.02-1.96) quartiles. Findings were robust to varied model specifications. Maternal residential exposures to industrial pollution were associated with increased ID prevalence in Utah. Since environmental correlates of ID are understudied, additional research is needed.

Social disparities in neighborhood heat in the Northeast United States.

Upward trends in ground-level warming are expected to intensify, affecting the health of human populations. Specific to the United States, the Northeast (NE) region is one of the most vulnerable to these warming trends. Previous research has found social disparities in the distribution of heat, while recent studies have examined associations between metropolitan racial/ethnic segregation and heat exposures. We advance upon previous research by including a novel measure of neighborhood-level racial/ethnic diversity in our examination of social inequalities in heat for NE neighborhoods (census tracts). We paired data derived from the United States Geological Survey on mean land surface temperature (LST) for the summer months of 2013-2017 with sociodemographic data from the American Community Survey (5-year estimates, 2013-2017). We use multivariable generalized estimating equations (GEEs) that adjust for geographic clustering. Findings reveal heat exposure disparities across NE neighborhoods. Neighborhoods with higher proportions of racial/ethnic minorities, people of lower socioeconomic status, households without access to an automobile, and greater diversity experience higher temperatures. Diversity was more strongly related to increased heat in neighborhoods with lower Latinx and lower Black composition suggesting that neighborhood homogeneity confers a differentially greater cooling effect based on higher White composition. The social groups that carry the unequal thermal burdens are also those who are most vulnerable. Interventions to reduce heat risks in the NE should therefore prioritize reducing the burden on historically disadvantaged communities.

Multigenerational immigrant trajectories and children's unequal exposure to fine particulate matter in the US.

Fine particulate matter is a serious health threat and exposures are particularly damaging for children. The environmental justice (EJ) literature shows that racial/ethnic minority communities experience disproportionate exposure to particulate pollution in the US. While important, those EJ studies tend to neglect people's complex identities, including their nativity and their families' generational histories of residence in the US. Yet there is growing interest in the intersection of immigrant populations and EJ. Our use of individual-level data enables examination of immigrant generational status by race/ethnicity, which provides insights on the intergenerational persistence of environmental injustice. We pair data on 12,570 US third graders (from 2013 to 2014) collected through the Early Childhood Longitudinal Survey with PM2.5 concentrations for the census tracts of their home and school locations. We apply generalized estimating equations to test for intergenerational disparities in exposure and to examine how those disparities vary between racial/ethnic groups. Independent of race/ethnicity, first- and second-generation children have greater PM2.5 exposure than 2.5- and third-generation children. However, generational status disparities in exposures vary based on race/ethnicity. First-generation White children face greater exposure than White children of later generational statuses, with inequalities attenuating by the second generation. In contrast, Hispanic/Latinx children experience no significant drop in exposure until the third generation. Among Asian and Black children, generational status was not a significant determinant of exposure. Results quantify the intergenerational persistence of environmental injustices for persons of color while showing the amelioration of inequalities for Whites after just one generation is born in the US, reflecting another facet of White privilege in the US.