Air Pollution, Epigenetic Alterations and Low Birth Weight.

Abstract

Air pollution has become a significant public health concern around the world. This research aimed at investigating the association between air pollution, epigenetic markers and low birth weight (LBW) among pregnant women recruited in urban (Beirut) and rural (Zahle) areas of Lebanon. Participants were interviewed to obtain information on demographic, lifestyle and exposure variables. Cord blood samples and birth weight data was collected by the gynecologists after delivery. Black Carbon (BC) measured by MicroAeth 350 aethalometers was used as a marker of outdoor air pollution and cigarette and water-pipe smoking as proxies of indoor pollution. A multivariate regression model was adopted to study the significant covariates, epigenetic alterations and their association with LBW. BC levels varied between urban (Beirut) and rural (Zahle) as well as across area types in Beirut. No significant association was shown between BC and epigenetics or birth weight. As for indoor exposure, in the adjusted model cigarette smoking was the only variable associated with a -331 close to significant decrease in LBW 95% CI [-20; 683]. In other correlation tests, “cigarette smoking” was associated with a hypo-methylation at the AHRR gene, “combined outdoor” variables and “time spent outdoors” were associated with 499g and 321g decrease in birth weight respectively, among Beirut participants. “Window ventilation” was associated with hyper-methylation at LINE-1 and ALU and “combined traffic” was associated with hypo-methylation at ALU and AHRR. Lastly, vitamin D supplementation during pregnancy was associated with a 304 g increase in birth weight. The findings of the study highlighted the complex relationship between air pollution, epigenetic alterations and LBW. Despite the challenges imposed by COVID-19 and the economic collapse, the study provided insights on the feasibility of recruitment and data collection at times of crisis in Lebanon. The air pollution methodology and data could serve in future pollution modelling studies across different areas types. Further studies with a larger sample size and methylome-wide analysis are needed to understand these associations and better inform public health interventions.

Date of Award	26 Mar 2025
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Andrew Povey (Supervisor) & Martie Van Tongeren (Supervisor)