Prenatal particulate air pollution and neurodevelopment in urban children: Examining sensitive windows and sex-specific associations

Abstract

Background Brain growth and structural organization occurs in stages beginning prenatally. Toxicants may impact neurodevelopment differently dependent upon exposure timing and fetal sex. Objectives We implemented innovative methodology to identify sensitive windows for the associations between prenatal particulate matter with diameter≤2.5μm (PM2.5) and children’s neurodevelopment. Methods We assessed 267 full-term urban children’s prenatal daily PM2.5 exposure using a validated satellite-based spatio-temporally resolved prediction model. Outcomes included IQ (WISC-IV), attention (omission errors [OEs], commission errors [CEs], hit reaction time [HRT], and HRT standard error [HRT-SE] on the Conners’ CPT-II), and memory (general memory [GM] index and its components - verbal [VEM] and visual [VIM] memory, and attention-concentration [AC] indices on the WRAML-2) assessed at age 6.5±0.98 years. To identify the role of exposure timing, we used distributed lag models to examine associations between weekly prenatal PM2.5 exposure and neurodevelopment. Sex-specific associations were also examined. Results Mothers were primarily minorities (60% Hispanic, 25% black); 69% had ≤12 years of education. Adjusting for maternal age, education, race, and smoking, we found associations between higher PM2.5 levels at 31–38 weeks with lower IQ, at 20–26 weeks gestation with increased OEs, at 32–36 weeks with slower HRT, and at 22–40 weeks with increased HRT-SE among boys, while significant associations were found in memory domains in girls (higher PM2.5 exposure at 18–26 weeks with reduced VIM, at 12–20 weeks with reduced GM). Conclusions Increased PM2.5 exposure in specific prenatal windows was associated with poorer function across memory and attention domains with variable associations based on sex. Refined determination of time window- and sex-specific associations may enhance insight into underlying mechanisms and identification of vulnerable subgroups.

Prenatal particulate air pollution exposure and body composition in urban preschool children: Examining sensitive windows and sex-specific associations

“…As described previously (Chiu et al, 2016), we used a validated hybrid satellite based spatio-temporal prediction model to estimate each woman’s prenatal exposure to PM 2.5 , an index of ambient pollution from traffic and other sources, based on residence over pregnancy (i.e., at enrollment and updated if they moved). In brief, the model combines the aerosol optical depth (AOD) data derived by Moderate Resolution Imaging Spectroradiometer (MODIS) at a 10 km spatial resolution with traditional land-use regression (LUR) predictors to yield residence-specific estimates of daily PM 2.5 , as detailed elsewhere (Kloog et al, 2011).…”

“…Using a constrained DLM, we estimate the time-varying association for each participant’s weekly exposures throughout the gestational period and anthropometric outcomes. Significant sensitive exposure windows were identified as weeks during pregnancy with a statistically significant association as previously described (Chiu et al, 2016; Hsu et al, 2015). …”

“…In addition, animal data demonstrate sex-specific vulnerability to prenatal oxidant injury (Minghetti et al, 2013), which has been linked to both air pollution and infant growth (Sun et al, 2009). Recent analyses from our group combined advanced statistical methods with highly temporally resolved exposure data to more objectively identify susceptibility windows and enhance the power to detect associations and identify vulnerable groups (i.e., effect modification) (Chiu et al, 2016; Hsu et al, 2015). These analyses demonstrated sex-specific and time-varying associations of prenatal air pollution exposure on asthma and neurodevelopmental outcomes in children, but to our knowledge, this has not yet been examined for early childhood growth indicators.…”

miRNAs Differentially Expressed by Next-Generation Sequencing in Cord Blood Buffy Coat Samples of Boys and Girls

“…While use of cord blood is a potential limitation in our study, the growing consensus is that blood can serve as an appropriate and informative model for studies of epigenetic mechanisms in birth cohorts. The effects of host factors in blood need further investigation and this data may contribute to identifying sensitive windows [105] that can be used as opportunities for therapy [106].…”

Maternal residential air pollution and placental imprinted gene expression

“…Maternal PM 2.5 exposures have also been linked to other adverse outcomes, including alterations in child neurodevelopment (Chiu et al 2016; Suades-Gonzalez et al 2015). Many of the placental imprinted genes associated with PM 2.5 have important functions in the brain and in neurodevelopment such as CDKN1C, FAM50B, NPAP1, PHLDA2, SLC22A18AS, SHANK2 , and UBE3A .…”