Air pollution affects respiratory health in children with asthma

The study, available online today, analyzes the short-term effects of outdoor pollution levels on asthma symptoms and lung function in children. The study was supported by the National Institutes of Health (NIH) and the Environmental Protection Agency (EPA).

Using data collected from the NIAID Inner-City Asthma Study (ICAS), researchers examined 861 children with persistent asthma, aged 5 to 12 years, living in low-income areas in seven U.S. inner-city communities: Boston, the Bronx, Chicago, Dallas, New York City, Seattle and Tucson. Over two years, the researchers regularly monitored the children’s asthma symptoms, breathing function, and school absences, and obtained daily outdoor pollution measurements from the EPA’s Aerometric Information Retrieval System. Every six months, they tested lung function twice-daily over a two-week period. They also asked the children’s parents for their observations of their children’s symptoms.

Results revealed that children had significantly decreased lung function following exposure to higher concentrations of the air pollutants sulfur dioxide, airborne fine particles, and nitrogen dioxide. Higher nitrogen dioxide levels and higher levels of fine particles also were associated with school absences related to asthma, and higher nitrogen dioxide levels were associated with more asthma symptoms. Because nitrogen dioxide is derived mainly from motor vehicle exhaust, these data provide evidence that car emissions may be causing adverse respiratory health effects in these urban children who have asthma.

Previous studies have documented the adverse respiratory effects of very high levels of outdoor pollutants. However, this study involves a larger cohort of inner-city asthmatic children and a more comprehensive evaluation of respiratory health effects than prior studies of this type. The study’s authors report that inner-city children with asthma experience adverse health effects from air pollutants even when air pollution levels are within the current air quality standards of the Environmental Protection Agency. These findings raise questions about the current air quality standards and suggest that part of overall asthma management for children living in inner cities may need to include efforts to reduce exposure to air pollutants.

The study was conducted by the Inner City Asthma Study Group (ICAS). ICAS was started in 1996 to examine environmental interventions in the management of asthma. During its 12-year history, ICAS has contributed to the understanding of childhood asthma and ways to minimize disease consequences. The study was funded by NIH’s National Institute of Allergy and Infectious Diseases (NIAID), National Institute of Environmental Health Sciences (NIEHS), and National Center for Research Resources (NCRR); and by the United States Environmental Protection Agency.

ARTICLE: G O’Connor et al. Acute respiratory health effects of air pollution on asthmatic children in US inner cities. Journal of Allergy and Clinical Immunology (2008).

WHO: Marshall Plaut, M.D., Chief, Allergic Mechanisms Section, NIAID; and Alkis Togias, M.D., Section Chief, Asthma, Allergy and Inflammation Branch, at NIH’s National Institute of Allergy and Infectious Diseases are available to comment on this article.

CONTACT: To schedule interviews, contact the NIAID Communications Office, 301-402-1663, niaidnews@niaid.nih.gov

NIAID is a component of the National Institutes of Health. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on basic immunology, transplantation and immune-related disorders, including autoimmune diseases, asthma and allergies.

The primary mission of the National Institute of Environmental Health Sciences (NIEHS), one of 27 Institutes and Centers at the National Institutes of Health, is to reduce the burden of human illness and disability by understanding how the environment influences the development and progression of human disease. For additional information, visit the NIEHS Web site at http://www.niehs.nih.gov/.

NCRR (http://www.ncrr.nih.gov) provides laboratory scientists and clinical researchers with the environments and tools they need to understand, detect, treat, and prevent a wide range of diseases.

The National Institutes of Health (NIH)–The Nation's Medical Research Agency–includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.