Why the School Environment is Important for Kids with Asthma
January 8, 2019
Exposure to allergens in the environment, and in particular indoor allergens, plays a significant part in the development of allergic diseases, including asthma, hay fever symptoms, and eczema. The common indoor allergens include house dust mites, cockroaches, rodents, furry pets such as cats and dogs, and molds. Environmental allergens can cause asthma and worsen symptoms. They can also lead to a certain type of asthma called “allergic asthma.”
Asthma is a chronic disease that affects a large proportion of children in the United States, accounting for more than 14 million missed school days per year and costing billions of dollars in healthcare use. Studies show that about eight out of every ten children with asthma are allergic to at least one indoor allergen. This is especially true for children who are older than three years.
Indoor allergen exposure in inner-city homes has garnered a great deal of attention, since children living in these areas have greater asthma severity, decreased asthma control, and greater healthcare use. We know that children are likely to become allergic to the allergens that predominate in their local environment. Therefore, the effects of these individual allergens will vary depending on the socioeconomic status, weather, and geographical location, among many other factors.
While years of previous research have linked exposures in the urban home environment with significant childhood asthma disease, many of these allergens are also present in inner-city school environments. This is noteworthy, since children spend 7 to 12 hours per day in school. Therefore, while the home environment is important, consideration should also be given to other places where the child spends time, such as school and daycare.
Our group recently published in JAMA Pediatrics a comprehensive study looking at the effect of school-specific allergen exposures on asthma illness among students, while accounting for home exposures as well.
This study focused on 284 students with asthma from 37 inner-city elementary schools in the Northeastern United States between March 1, 2008 and August 31, 2013. Each child was followed clinically for one academic school year.
During that same school year, classroom and home dust samples were collected by the research team and analyzed for common indoor allergens. The children had their lung function tested at various times and parents were interviewed about their child’s asthma symptoms periodically during the year.
In this study, we found that mouse, cat, and dog allergens were commonly detected in the dust samples obtained from inner-city schools. However, the levels of mouse allergen prevailed with significantly higher levels in schools than in students’ homes (median settled dust level, 0.90 vs 0.14 µg/g; P <0.001).
Furthermore, exposure to higher levels of mouse allergen in school was associated with increased asthma symptoms and lower lung function. This was not true for the other indoor allergens tested. These findings demonstrate that the school environment might be an important contributor to childhood asthma.
While we discovered high levels of mouse allergen in these schools, other cities might have different predominant allergens in their schools because of location. For instance, we found undetectable or low levels of cockroaches and dust mites in these schools, but other cities with warmer climates and different building conditions have demonstrated high levels of these allergens.
It is also important to understand that asthma involves a number of factors and that it is difficult to identify one allergen exposure as the cause. The take-home message is that schools can be a source of allergen exposure connected to asthma disease.
Limiting allergen exposure is an important part of preventing asthma attacks. School-based environmental interventions may offer benefits for this problem and have the potential to help many children with asthma at once.
A school-based environmental study is currently underway to help answer this question, employing pest management techniques and other tactics. While parents might not have control over the school environment, they can help control the home environment.
The best protection is to know your child’s environmental allergens. Healthcare providers have a responsibility to ask about environmental exposures and to ensure that patients have the knowledge and resources to implement environmental control measures.
Once environmental exposures are identified, an allergy consultation visit should be placed for skin testing to better define exposure risk, especially for children with asthma. Low-cost environmental interventions are a reasonable first start, with costly interventions reserved for after an allergy consultation is completed. Environmental control measures can and should supplement good medical care.
Perdita Permaul, MD, completed a fellowship in Allergy and Immunology at Boston Children’s Hospital. She completed her pediatric residency at New York Presbyterian-Weill Cornell Medical Center in New York City and her medical degree at the Mount Sinai School of Medicine. Currently, she is an Attending physician in the Division of Pediatric Allergy and Immunology at Massachusetts General Hospital for Children and Instructor of Pediatrics at Harvard Medical School. Dr. Permaul is involved in asthma and food allergy clinical research, and has authored a number of papers. She is committed to advancing the care of those with allergies and asthma. William J. Sheehan, MD, is a pediatric allergist and immunologist at Boston Children's Hospital and an assistant professor at Harvard Medical School. He specializes in allergies and asthma and has a research focus on asthma in the inner-city. Wanda Phipatanakul, MD, MS, has dedicated much of her career to clinical research aimed at reducing and preventing asthma and allergic diseases in children, particularly inner-city children. She directs the Asthma Clinical Research Center at Boston Children’s Hospital and is an associate professor of Pediatrics at Harvard Medical School. Originally from St. Louis, she earned her medical degree from Loma Linda University and completed her residency in pediatrics at Children’s Hospital Los Angeles in 1997. After a fellowship in immunology at Johns Hopkins University, she joined the faculty in the Division of Immunology and Allergy at Boston Children’s and Harvard Medical School, where she has remained for the past 17 years. She holds a Master of Science in clinical epidemiology from the Harvard School of Public Health. Dr. Phipatanakul has built a deep network of community relationships, and she conducts both school- and home-based asthma studies with inner-city children. Her work was the first to document the relationship between mouse infestations in urban apartments and asthma; she was also the first to comprehensively evaluate how allergen exposures at school affect allergic disease outcomes in children, adjusting for exposures at home. From there, she leads a comprehensive National Institutes of Health (NIH)-funded school-based environmental trial, the School Inner-City Asthma Intervention Study.