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

Environ Int. 2016 Feb;87:56-65. doi: 10.1016/j.envint.2015.11.010. Epub 2015 Nov 28.

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 ≤ 2.5 μm (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 may be 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.

Keywords: Air pollution; Neurodevelopment; Particulate matter; Prenatal exposure; Sensitive windows; Sex-specific associations.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Air Pollutants / analysis
  • Air Pollutants / toxicity*
  • Attention / drug effects
  • Child
  • Child Development / drug effects
  • Child, Preschool
  • Female
  • Gestational Age
  • Humans
  • Intelligence / drug effects
  • Male
  • Maternal Exposure / adverse effects*
  • Memory / drug effects
  • Models, Theoretical
  • Neurodevelopmental Disorders / chemically induced*
  • Neurodevelopmental Disorders / epidemiology
  • Neurodevelopmental Disorders / physiopathology
  • Particulate Matter / analysis
  • Particulate Matter / toxicity*
  • Pregnancy
  • Prenatal Exposure Delayed Effects / chemically induced*
  • Prenatal Exposure Delayed Effects / epidemiology
  • Prenatal Exposure Delayed Effects / physiopathology
  • Sex Factors
  • Smoking
  • United States
  • Urban Population*

Substances

  • Air Pollutants
  • Particulate Matter