Exposure to landscape fire smoke reduced birthweight in low- and middle-income countries: findings from a siblings-matched case-control study
Abstract
Landscape fire smoke (LFS) has been associated with reduced birthweight, but evidence from low- and middle-income countries (LMICs) is rare. Here, we present a sibling-matched case-control study of 227,948 newborns to identify an association between fire-sourced fine particulate matter (PM2.5) and birthweight in 54 LMICs from 2000 to 2014. We selected mothers from the geocoded Demographic and Health Survey with at least two children and valid birthweight records. Newborns affiliated with the same mother were defined as a family group. Gestational exposure to LFS was assessed in each newborn using the concentration of fire-sourced PM2.5. We determined the associations of the within-group variations in LFS exposure with birthweight differences between matched siblings using a fixed-effects regression model. Additionally, we analyzed the binary outcomes of low birthweight (LBW) or very low birthweight (VLBW). According to fully adjusted models, a 1 µg/m3 increase in the concentration of fire-sourced PM2.5 was significantly associated with a 2.17 g (95% confidence interval [CI]: 0.56-3.77) reduction in birthweight, a 2.80% (95% CI: 0.97-4.66) increase in LBW risk, and an 11.68% (95% CI: 3.59-20.40) increase in VLBW risk. Our findings indicate that gestational exposure to LFS harms fetal health.
Data availability
All data analysed during this study are included in the manuscript are from publicly sources, and their accesses are included in the manuscript and supporting files. Specifically, the health data can be directly accessed from the Demographic and Health Surveys website, https://www.dhsprogram.com/, after a free registration.
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Demographic and Health SurveysNot applicable (No DOI for DHS database).
Article and author information
Author details
Funding
PKU-Baidu Fund (2020BD031)
- Tao Xue
Fundamental Research Funds for the Central Universities (BMU2021YJ042)
- Tao Xue
CAMS Innovation Fund for Medical Sciences (2017-I2M-1-004)
- Tianjia Guan
Energy Foundation
- Tao Xue
National Natural Science Foundation of China (4217050142)
- Tao Xue
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: Procedures and questionnaires for standard DHS surveys have been reviewed and approved by ICF Institutional Review Board. All analyses are based on the open-accessed DHS data. The research plan has been approved by DHS, and all analyses adhere the guideline of data usage from DHS.
Copyright
© 2021, Li et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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