The exhaust fumes, soot and dust thrown up by traffic in the capital of the United Kingdom can put at risk the health of thousands of unborn babies.
The findings come from a study of more than half a million babies, which suggests that pregnant mothers exposed to air pollution from crowded roads in London are more likely to deliver babies with low birth weight or smaller babies. what they should. However, when it comes to traffic-related noise, they found no conclusive effect on the health of the babies.
According to the authors, reducing the average concentration of fine particle pollution emitted by city traffic by only 10% could prevent 90 babies per year (3% of cases) born with low birth weight.
They add that the findings could be applicable to other cities in the United Kingdom and throughout Europe with comparable levels of traffic pollution, highlighting the need for health policies to improve air quality in urban areas.
Making the connection
Previous studies have shown a link between air pollution, complications of pregnancy and childhood diseases, but studies on acoustic contamination in pregnancy have yielded conflicting results.
In the latest study, published in The BMJ, a group led by the Imperial College of London analyzed the link between exposure to air and noise pollution caused by transit during pregnancy and the effect on weight measurements at birth, both low birth weight (less than 2500 g) and small for gestational age.
A small but significant proportion of underweight babies in London is directly attributable to exposure to air pollution
– Dr. Mireille Toledano
Conducted at the Environment Center and Health MRC-PHE at Imperial College London and Kings College London, the research focused on the records of more than half a million (540,365) babies born in the London metropolitan area between 2006 and 2010, along with the location of the address of the house of the mother. [RBS1]
Using air quality data from a government emissions database, the researchers calculated average monthly concentrations of traffic-related pollutants, including nitrogen dioxide (NO2), nitrogen oxides (NOx), and particles fine (PM ] 2.5 ) of exhaust and non-exhaust exhaust sources, such as brakes or tire wear, as well as larger particles (PM 10 ). The average noise levels of road traffic during the day and night were also estimated.
Small particles, large impact
Analyzing the data, they found higher levels of these air pollutants, particularly PM 2.5 were associated with 2% to 6% probability of low birth weight and 1% to 3% more likely to be small for gestational age.
"Our study has shown that a small but significant proportion of underweight babies in London is directly attributable to exposure to air pollution, particularly to small particles produced by road traffic." Said Dr. Mireille Toledano , from the School of Public Health in Imperial and principal author of the research.
He added: "Babies who are born with low birth weight or who are small for their gestational age have a higher risk of dying within their first month, as well as diseases in later life, such as cardiovascular disease. reducing traffic pollution in urban environments could help reduce the health impact of unborn babies and their lifetime risk of disease. "
They add that the limitations of the study include the possibility of misclassification exposure, for example, because exposure was estimated in the mother's residential address and did not take into account exposure elsewhere, and those estimates were used for other risk factors, such as passive smoking in the home.
However, researchers are confident that the study data are robust and provide evidence for policy makers in the United Kingdom.
Role of unconfirmed noise
Explain that although the effects of traffic noise can not be ruled out, evidence of an association between exposure to air pollution and poor health of unborn babies the urban environment is clear, although the biological mechanisms of pollution of road traffic in public Physical health is not fully understood.
Dr. Rachel Smith, also of the School of Public Health and lead author of the study, said: "As far as we know, this is the largest study in the United Kingdom to analyze the effects of air. at birth, and the largest study worldwide to observe the effect of noise exposure on birth weight.
"Although the research did not show an effect independent of noise on birth weight, we can not rule it out as a potential factor.
"What is clear, however, is the effect that air pollution generated by traffic is having on fetal development." We have shown that exposure during pregnancy to traffic pollution has a detrimental effect on the health of babies in Greater London. "
The research was supported by the Natural Environment Research Council of the United Kingdom, the Council for Medical Research and the Economic and Social Research Council, the Department of Environment, Food and Rural Affairs, and the Department of Health, through a cross-cutting Environmental Exposures & Health Initiative research council, with the additional support of Public Health England and the National Institute for Health Research.
–  & # 39; Impact of air and noise pollution of traffic in London on birth weight: a retrospective population-based cohort study & # 39; by Rachel B Smith et al., Published in The BMJ.
This article is based on materials provided by The BMJ.
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