New research by the Centre for Environmental Health and Sustainability (CESH) at the University of Leicester indicates that exposure to air pollution from road traffic as early as the first trimester of pregnancy and in early life is associated with small but significant reductions in children's lung function at the age of eight years. The research is being presented this week at the European Respiratory Congress in Madrid.
The research drew on data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a long-term health study of 14,500 children born in the former county of Avon in 1991 and 1992, and their families. ALSPAC is the largest study to investigate the impact of particulate matter (PM10) from different sources, including road traffic, on lung development and growth, and to analyze it by each trimester of pregnancy, as well as during infancy and childhood.
The researchers did not see similar associations between traffic pollution and lung function in children at the age of 15 years: "We think this may be because air pollution levels, particularly diesel emissions, were reducing over the time that the lung function was increasing in these analyses," said Professor Hansell. "However, it is also possible that the effect of air pollution is small and that lung growth is able to outpace the adverse effects by teenage years."
She said it was unclear how traffic pollution could affect childhood lung function, particularly during pregnancy. One mechanism could be that particles cross the placenta and disturb the development of the growing fetus's lungs through oxidative stress (an imbalance between free radical molecules and antioxidants). Another mechanism could be that prenatal exposure could induce epigenetic changes (changes in gene function that do not involve changes in DNA sequences).
Professor Hansell concluded:
"It's really important to prioritize reduction of air pollution levels to improve respiratory health. In separate work, we have also shown associations with lower lung function in adulthood, suggesting that air pollution contributes to the aging of the lungs. Lung health is a marker of general health and associated with numerous other chronic diseases."
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