Study leader, Amy Padula, PhD, a post-doctoral fellow at the University of California in Berkeley declared:
“In this study, we found that prenatal exposures to airborne particles and the pollutant nitrogen dioxide adversely affect pulmonary function growth among asthmatic children between 6 and 15 years of age. This analysis adds to the evidence that maternal exposure to ambient air pollutants can have persistent effects on lung function development in children with asthma.”
The study, which was part of the Fresno Asthmatic Children’s Environment Study (FACES), a Lifetime Exposure initiative that examines the impact of prenatal exposure to various ambient air pollutants on children’s and adolescent’s growth of lung function in high pollution areas included repeat evaluations of 162 asthmatic children aged between 6 and 15 years and their mothers.
The researchers traced the mothers’ residences during pregnancy and obtained the corresponding concentrations of pollutants from the Aerometric Information Retrieval System supported by the U.S. Environmental Protection Agency (EPA) to determine the prenatal pollutant exposure levels. The team obtained monthly average concentrations of pollutants, including carbon monoxide, nitrogen dioxide, ozone and particulate matter from 24-hour averages at a central site monitor, before calculating summaries for the entire pregnancy and each trimester.
The researchers used spirometry to calculate the children’s’ lung function growth, which is mainly determined by changes in lung capacity as a child grows. Spirometry is a common pulmonary function test that evaluates the amount and velocity of air that can be inhaled and exhaled in four different measures:
The FVC (Forced Vital Capacity), i.e. the volume of air that can be expelled after a full inhalation.
The FEV1 (Forced Expiratory Volume in 1 second), i.e. the volume of air that can forcibly be expelled in one second after a full inhalation
The FEF (Forced Expiratory Flow), i.e. the speed of air from the lung during the middle portion of a forced expiration.
The PEF (Peak Expiratory Flow), i.e. the maximal speed of air expelled immediately after being inhaled. All pulmonary function tests were performed multiple times for boys and girls separately, with the team noting any important changes in addition to adjusting the measures for the children’s height, age, race and socioeconomic status.
The findings revealed that exposure to nitrogen dioxide during the first and second pregnancy trimesters were linked to lower pulmonary function growth in both genders in childhood. Girls who were exposed to nitrogen dioxide during the first trimester were linked to lower FEV1 growth, whilst nitrogen dioxide exposure during the second trimester was linked to lower FEF growth. Boys exposed to nitrogen dioxide exposure during the first and second trimesters of pregnancy were linked to lower FVC growth. The researchers also noted that whilst exposure to particulate matter during the first trimester was linked to lower FEV1 and FVC growth in girls, boys with similar exposures during the third trimester were linked to lower PEF and FEF growth.
Dr. Padula states: “This finding adds to the evidence that current air pollution levels continue to have adverse effects on human health. Few studies have examined prenatal exposure to air pollution and subsequent lung function in childhood. These results suggest that we need to be doing a better job to reduce traffic-related air pollution.”
She continued saying that her team anticipates to perform further research to investigate the impact of genetic susceptibility to air pollution, and concludes:
“Currently, our studies are examining the associations between prenatal air pollution and adverse birth outcomes. It would be useful to know what makes some people more or less susceptible to the adverse affects of air pollution so we might be able to provide more targeted public health advice.”