Women exposed to smoke from landscape fires during pregnancy are more likely to give birth to babies with low or very low birth weight, according to findings published in eLife.
The study is the first to report a link between low birth weight and exposure to fire smoke in low- and middle-income countries (LMICs), where 90% of babies are low birth weight and landscape fires predominate.
Landscape fires, such as forest fires, tropical deforestation fires and the burning of agricultural biomass, play an important role in maintaining terrestrial ecosystems. Yet smoke from landscape fires is causing a costly and growing global public health problem, causing recurrent episodes of pollution, mostly affecting the LMIC.
Previous studies have shown that exposure to smoke from fire during pregnancy is associated with low birth weight, which is in itself a public health problem at LMIC. Reducing the risk of low birth weight is one of the global goals of the World Health Organization for 2025.
Low birth weight babies are at higher risk for a number of diseases later in life than normal weight babies. Several studies have shown the effects of landscape fire smoke on acute lung and heart disease, but the effects of these pollutants on the health of susceptible pregnant women are not well known. We wanted to study the relationship between birth weight and exposure to fire source pollution in several countries and over a long period of time. “
Jiajianghui Li, co-author, PhD student, Institute of Reproductive and Child Health, School of Public Health Science Center, Peking University, China
The researchers conducted a case-control study at 54 LMICs, where they compared 108,137 groups of siblings with their mothers. They used research conducted by the United States Agency for International Development between 2000 and 2014 to find information on the birth weight of siblings and other health and demographic factors. They then estimated the exposure to contaminants from landscape fires, using fire emission data from the global fire emission database and a model that converts these data into terrestrial surface concentrations of particulate matter in different regions.
Their analysis showed that an increase in exposure to one microgram per cubic meter of fire dust particles was associated with a 2.17 gram decrease in birth weight. “The effect was even more pronounced when we looked at whether exposure to fire smoke was associated with low or very low birth weight; for every microgram per cubic meter increase in particulate matter exposure, the risks of low and very low birth weight increase by about three and 12 percent, respectively, “says co-author Tianjia Guan, assistant professor in the Department of Health Policy, School of Health Policy. and Management, Chinese Academy of Medical Sciences and Beijing Union Medical College, China.
Researchers have found that very low birth weight is most strongly associated with pollution. To understand why, they developed a model that looks at the average birth weight of babies in single families. Newborns in families who had a moderately lower birth weight were more susceptible to the risks of smoke contamination from fire than those who had a moderate initial birth weight. “This suggests that other factors affecting maternal and fetal health, such as maternal nutrition or employment, may make mothers and their developing babies even more vulnerable to the risks of contamination,” said co-author Qian Guo, a doctoral student at the university. School of Energy and Environmental Engineering, University of Science and Technology, China.
“Our global sibling study found a link between exposure to landscape pollution during pregnancy and reduced birth weight in low- and middle-income countries,” said Tao Xue, a senior fellow at the Institute of Reproductive and Childhood. Health, School of Public Health School Center, Peking University. “Newborns from families with lower birth weights are more vulnerable. It is important to develop steps to reduce the incidence of landscape fires, for example by mitigating climate change in order to protect the health of mothers and babies in these vulnerable groups. “
Reference in the magazine:
Lee, J., et al. (2021) Exposure to smoke from a landscape fire reduces birth weight in low- and middle-income countries: findings from a case-control study compared between siblings. eLife. doi.org/10.7554/eLife.69298.