May is Asthma Awareness Month, and the National Institutes of Health (NIH) is finding solutions to improve the health of the nearly 25 million people in the United States who have asthma. In recent decades, the prevalence of asthma has been increasing, resulting in millions of urgent medical visits and missed days of work and school each year.
Asthma is a chronic, and sometimes fatal, disease in which the airways become inflamed from a variety of triggers in the air, like indoor allergens from dust mites, mold, and cockroaches, and outdoor air pollution. Once the airways become swollen and inflamed, they become narrower, causing symptoms such as wheezing, coughing, chest tightness, and difficulty breathing.
Together, three institutes lead asthma research at NIH.
- The National Institute of Environmental Health Sciences (NIEHS).
- The National Heart, Lung, and Blood Institute (NHLBI).
- The National Institute of Allergy and Infectious Diseases (NIAID).
These institutes support different aspects of asthma research but are united in a commitment to reduce the burden of this debilitating disease, as highlighted here through recent studies funded collaboratively by all three institutes.
Studies in schools
Research funded by NIEHS, NHLBI, and NIAID has demonstrated the importance of healthy school environments. A study of students from inner-city schools, published in January 2017, linked airborne mouse allergens at schools to increased symptoms and decreased lung function in asthmatic children. This suggests there are steps schools can take to improve air quality and potentially benefit children with asthma.
A preliminary study tested high-efficiency particulate air filters, known as HEPA filters, in three urban elementary schools. The researchers reported two indoor air quality improvements — about a 40 percent reduction in fine dust particles, along with about a 55 percent reduction in traffic-related black carbon levels. Both pollutants can irritate the lungs of people with asthma.
NIH-supported researchers also are evaluating how much outdoor air pollution may come inside school buildings. One study found that levels of traffic-related black carbon were lower inside than outside, but when outdoor levels increased, so did the indoor levels. Fine dust particles inside schools came from both indoor and outdoor sources.
Complex role of immune system
In addition to studying school environments, research funded by NIEHS, NHLBI, and NIAID has explored the complex role of the immune system in asthma. A study published in 2016 showed that children exposed to a wide range of bacteria and microbes , as found in dust on traditional Amish farms that use animals rather than machines, may be protected against asthma through the stimulation and shaping of nonspecific, or innate, immune responses.
The study took genetic factors into account by comparing genetically similar Amish and Hutterite children who live in communities with different agricultural practices. The researchers further strengthened the findings by reproducing the observed protective effect in mouse studies. The difference in triggering of the innate immune response may help explain why asthma remains rare among the Amish but affects nearly 1 in 10 U.S. children, who typically do not live in a rich microbial environment.
Although bacteria and microbes can benefit the immune system, exposure to mold may make asthma worse. Scientists funded by NIEHS, NHLBI, and NIAID showed that children with high exposure to molds and fungi were more likely to have asthma at age 7. For children with allergies, the association was especially strong.
NIH-supported scientists continue to work to prevent and treat asthma. This month, we honor those children and adults who face the challenges of asthma every day, those who participate in clinical studies, and the researchers and health care professionals who help to address this condition.
Sheehan WJ, Permaul P, Petty CR, Coull BA, Baxi SN, Gaffin JM, Lai PS, Gold DR, Phipatanakul W. 2017. Association between allergen exposure in inner-city schools and asthma morbidity among students. JAMA Pediatr 171(1):31–38.
Jhun I, Gaffin JM, Coull BA, Huffaker MF, Petty CR, Sheehan WJ, Baxi SN, Lai PS, Kang CM, Wolfson JM, Gold DR, Koutrakis P, Phipatanakul W. 2017. School environmental intervention to reduce particulate pollutant exposures for children with asthma. J Allergy Clin Immunol Pract 5(1):154–159.
Gaffin JM, Petty CR, Hauptman M, Kang CM, Wolfson JM, Abu Awad Y, Di Q, Lai PS, Sheehan WJ, Baxi S, Coull BA, Schwartz JD, Gold DR, Koutrakis P, Phipatanakul W. 2016. Modeling indoor particulate exposures in inner-city school classrooms. J Expo Sci Environ Epidemiol; doi:10.1038/jes.2016.52 [Online 7 September 2016].
Stein MM, Hrusch CL, Gozdz J, Igartua C, Pivniouk V, Murray SE, Ledford JG, Marques dos Santos M, Anderson RL, Metwali N, Neilson JW, Maier RM, Gilbert JA, Holbreich M, Thorne PS, Martinez FD, von Mutius E, Vercelli D, Ober C, Sperling AI. 2016. Innate immunity and asthma risk in Amish and Hutterite farm children. N Engl J Med 375(5):411–421.
Zhang Z, Biagini Myers JM, Brandt EB, Ryan PH, Lindsey M, Mintz-Cole RA, Reponen T, Vesper SJ, Forde F, Ruff B, Bass SA, LeMasters G, Bernstein DI, Lockey J, Budelsky AL, Khurana Hershey GK. 2017. Beta-glucan exacerbates allergic asthma independent of fungal sensitization and promotes steroid-resistant TH2/TH17 responses. J Allergy Clin Immunol. 139(1):54-65.
(This story is based on an NIH press release.)