Residential proximity to major roads and neighbourhood green space in relation to biological stress in the second trimester of pregnancy in the IPANEMA cohort

Abstract

GREEN, AIR, LMIC: PECHAKUCHA COMES TO ISEE! Johan Friso Foyer, Floor 1, August 27, 2019, 10:30 AM - 12:00 PM Background/aim: Living near a major road during pregnancy has been associated with adverse birth outcomes. The underlying biological mechanisms however, are poorly understood. Major roads may act as an environmental stressor while natural environments may reduce biological stress. Cortisol is the body’s main stress hormone. The cortisol concentration in scalp hair (HCC) is a retrospective measure of long-term cortisol secretion This study aimed to investigate second trimester HCC in 129 mothers of the IPANEMA pregnancy cohort (Impact of Particulate Matter on mother and babies in Antwerp) in relation to residential proximity to major roads and access to neighbourhood green space (NGS). Method: Residential proximity to major roads and access to NGS were calculated using ArcGIS. NGS was defined as 10 hectares of green space within an 800 m buffer from the participant’s residence. Hair samples were analysed using High-Performance Liquid Chromatography in combination with triple quadropole mass spectrometry. Limit of quantification was 1.0 pg/mg hair. A stepwise multiple regression model was built, HCC and distance to roads were logarithmically transformed. Results: The geometric mean HCC was 3.99 (95% CI: 3.54-4.5) pg/mg hair. In a model, corrected for season of sampling, access to NGS (p=0.019), distance to major roads (p=0.004), as well as the interaction between both (p=0.035) were significantly associated with HCC (R2=12.9%). The model predicted 15% higher HCC when living at an average distance (308 meters) from a major road in the absence of NGS compared to living at the same distance with access to NGS (4.15 (3.19-5.4) versus 3.61 (3.14-4.17) pg/mg hair). Conclusion: Results suggest that proximity to a major road may activate cortisol secretion and biological stress whereas access to neighbourhood green space may have a moderating effect. Our findings, if confirmed, may contribute to evidence-based urban planning towards greener environments.