In-utero exposure to indoor air pollution or tobacco smoke and cognitive development in a South African birth cohort study

Grace M Christensen; Claire Rowcliffe; Junyu Chen; Aneesa Vanker; Nastassja Koen; Meaghan J Jones; Nicole Gladish; Nadia Hoffman; Kirsten A Donald; Catherine J Wedderburn; Michael S Kobor; Heather J Zar; Dan J Stein; Anke Hüls

doi:10.1016/j.scitotenv.2022.155394

In-utero exposure to indoor air pollution or tobacco smoke and cognitive development in a South African birth cohort study

Sci Total Environ. 2022 Aug 15:834:155394. doi: 10.1016/j.scitotenv.2022.155394. Epub 2022 Apr 20.

Authors

Affiliations

¹ Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
² Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, University of Cape Town, South Africa.
³ Neuroscience Institute, University of Cape Town, Cape Town, South Africa; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa; South African Medical Research Council (SAMRC) Unit on Risk and Resilience in Mental Disorders, University of Cape Town, Cape Town, South Africa.
⁴ Department of Biochemistry and Medical Genetics, University of Manitoba, Children's Hospital Research, Institute of Manitoba, Winnipeg, Canada.
⁵ Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada; Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada.
⁶ Neuroscience Institute, University of Cape Town, Cape Town, South Africa; Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa.
⁷ Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, University of Cape Town, South Africa; Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
⁸ Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, University of Cape Town, South Africa; Neuroscience Institute, University of Cape Town, Cape Town, South Africa; Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK.
⁹ Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, University of Cape Town, South Africa; South African Medical Research Council (SAMRC) Unit on Risk and Resilience in Mental Disorders, University of Cape Town, Cape Town, South Africa.
¹⁰ Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA; Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, USA. Electronic address: anke.huels@emory.edu.

Abstract

Background and aims: There is increasing evidence indicating that air pollution exposure is associated with neuronal damage. Since pregnancy is a critical window of vulnerability, air pollution exposure during this period could have adverse effects on neurodevelopment. This study aims 1) to analyze associations of prenatal exposure to indoor air pollution (particulate matter with diameters ≤10 μm, PM₁₀) and tobacco smoke with neurodevelopment and 2) to determine whether these associations are mediated by deviations of epigenetic gestational age from chronological gestational age (ΔGA).

Methods: Data of 734 children from the South African Drakenstein Child Health Study were analyzed. Prenatal PM₁₀ exposure was measured using devices placed in the families' homes. Maternal smoking during pregnancy was determined by maternal urine cotinine measures. The Bayley Scales of Infant and Toddler Development III (BSID-III) was used to measure cognition, language and motor development and adaptive behavior at two years of age. Linear regression models adjusted for maternal age, gestational age, sex of child, ancestry, birth weight/length, and socioeconomic status were used to explore associations between air pollutants and BSID-III scores. A mediation analysis was conducted to analyze if these associations were mediated by ΔGA using DNA methylation measurements from cord blood.

Results: An increase of one interquartile range in natural-log transformed PM₁₀ (lnPM₁₀; 1.58 μg/m³) was significantly associated with lower composite scores in cognition, language, and adaptive behavior sub-scores (composite score β-estimate [95%-confidence interval]: -0.950 [-1.821, -0.120]). Maternal smoking was significantly associated with lower adaptive behavior scores (-3.386 [-5.632, -1.139]). Associations were not significantly mediated by ΔGA (e.g., for PM₁₀ and cognition, proportion mediated [p-value]: 4% [0.52]).

Conclusion: We found an association of prenatal exposure to indoor air pollution (PM₁₀) and tobacco smoke on neurodevelopment at two years of age, particularly cognition, language, and adaptive behavior. Further research is needed to understand underlying biological mediators.

Keywords: Air pollution; Environmental epidemiology; Epigenomics; Neurodevelopment; Particulate matter.

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Air Pollution, Indoor* / adverse effects
Air Pollution, Indoor* / analysis
Birth Cohort
Cognition
Cohort Studies
Female
Humans
Infant
Maternal Exposure
Nicotiana
Particulate Matter / analysis
Pregnancy
Prenatal Exposure Delayed Effects* / chemically induced
Prenatal Exposure Delayed Effects* / epidemiology
South Africa
Tobacco Smoke Pollution* / adverse effects
Tobacco Smoke Pollution* / analysis

Substances

Air Pollutants
Particulate Matter
Tobacco Smoke Pollution

Abstract

MeSH terms

Substances

Grants and funding