Asthma attacks provoked by respiratory virus infections—a common trigger—have been studied extensively, but those that occur independently of such infections have not.
According to a National Institutes of Health-funded study, children and adolescents who reside in low-income urban areas are more likely to experience non-viral asthma attacks when exposed to moderate levels of two outdoor air pollutants, ozone and fine particulate matter.
Additionally, the study finds links between exposure to the two outdoor air pollutants and molecular alterations in the kids’ airways during non-viral asthma attacks, pointing to potential mechanisms for those attacks.
According to the researchers, the observational study is one of the first to link elevated concentrations of particular outdoor air pollutants in particular urban areas to distinct changes in the airways during asthma attacks that are not brought on by respiratory viruses. The Lancet, a journal, published the findings today.
“The strong association this study demonstrates between specific air pollutants among children in impoverished urban communities and non-viral asthma attacks further augments the evidence that reducing air pollution would improve human health,” said Hugh Auchincloss, M.D., acting director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH.
Under the direction of Matthew C. Altman, M.D., M.Phil., and Daniel J. Jackson, M.D., the study was carried out by the Inner City Asthma Consortium, which received funding from the NIAID. Dr. Altman is an associate scientist at the Benaroya Research Institute at Virginia Mason in Seattle as well as an associate professor in the department of medicine at the University of Washington School of Medicine.
At the University of Wisconsin-Madison School of Medicine and Public Health, Dr. Jackson teaches paediatrics and medicine.
Chronic airway inflammation is what causes asthma. The space for air to enter and exit the lungs is significantly reduced during an asthma attack because the muscles surrounding the airways tighten and the airways produce more mucus. Children who live in low-income urban environments in the United States are at particularly high risk for attack-prone asthma.
Asthma attacks provoked by respiratory virus infections—a common trigger—have been studied extensively, but those that occur independently of such infections have not.
In the current study, researchers looked at the association between air pollution levels and asthma attacks that happened in the absence of a respiratory virus in 208 children aged 6 to 17 who had attack-prone asthma and lived in low-income areas in one of nine U.S. cities.
Then, using data from an independent cohort of 189 children with persistent asthma, aged 6 to 20 years, who also resided in low-income neighbourhoods in four U.S. cities, the researchers confirmed the relationships they had discovered between air pollutant levels and non-viral asthma attacks.
For up to two respiratory illnesses or roughly six months, whichever came first, the researchers prospectively monitored the kids. Each illness was labelled as either viral or non-viral, as well as whether it involved an asthma attack or not.
The researchers matched each illness with air quality index values and levels of individual air pollutants recorded by the Environmental Protection Agency in the relevant city on the dates surrounding the illness. The investigators subsequently adjusted their data for city and season to decrease the impact of these variables on the findings.
According to previously published reports, the researchers discovered that nearly 30% of children had asthma attacks without a viral cause, which is two-to-three times the percentage seen in children living outside of cities. These attacks were linked to locally increased levels of ozone and fine particulate matter in the ambient air.
By examining nasal cell samples taken from the children while they were ill, the researchers were able to connect changes in the expression of particular gene sets that contribute to airway inflammation to increased levels of these two pollutants.
Certain gene-expression patterns have been identified, and they imply that distinct biological pathways might be at play in non-viral asthma attacks.
In light of the study’s findings, it will be crucial to create and test various strategies to determine whether they can prevent or reduce pollution-related asthma attacks in urban children.
These strategies may include treatments designed to counteract the harmful effects of elevated levels of outdoor air pollutants on airway inflammatory responses linked to non-viral asthma attacks and devices for personalised monitoring of local outdoor air pollutant levels to inform asthma management.
In order to better understand the causes of infectious and immune-mediated diseases and to develop better methods of preventing, diagnosing, and treating these illnesses, NIAID conducts and funds research at the National Institutes of Health (NIH), across the nation, and internationally. The NIAID website hosts news releases, fact sheets, and other materials that are related to the organisation.
The NIH (National Institutes of Health): The United States Department of Health and Human Services includes the NIH, the country’s medical research organisation, as one of its 27 institutes and centres.
The National Institutes of Health (NIH) is the main federal organisation conducting and funding basic, clinical, and translational medical research. Its work focuses on finding the causes, prognoses, and treatments for both common and rare diseases.