Exposure to higher-than-average levels of nitrogen dioxide (NO2), a component of motor vehicle exhaust, during the first year of life was associated with childhood asthma in Latino and African Americans, according to study results in the American Journal of Respiratory and Critical Care Medicine online ahead of print.
The study, which the authors deemed to be the largest to date of air pollution exposure and asthma risk in minority children in the U.S., showed a 17% increase in the risk of developing asthma later in life for every 5 parts per billion (ppb) increase in NO2 exposure during the first year.
In the research, scientists looked retrospectively at the study participants’ exposure to air pollution in early childhood, before they developed asthma. Children who developed asthma before this exposure period were excluded, according to lead author Katherine K. Nishimura, MPH.
“Any participant with asthma in this study was exposed to air pollution in infancy, before they developed the disease, which is a step in the right direction in inferring causality,” said Nishimura, a graduate student in the laboratory of senior author Esteban G. Burchard, MD, MPH, a UCSF professor of bioengineering and therapeutic sciences and medicine and director of the UCSF Center for Genes, Environment & Health
The study involved 3,343 Latino and 977 African American participants.