Allergies in the Inner City that Trigger Asthma in Children

Asthma Fast Facts:

  • Over 9 million U.S. children under 18 years of age (13%) have ever been diagnosed with asthma, and 6.5 million children (9%) still have asthma.
  • Men are more likely to have ever been diagnosed with asthma or to still have asthma than women.
  • Non-Hispanic black children are more likely to have ever been diagnosed with asthma or to still have asthma than Hispanic children or non-Hispanic white children.
  • Children in poor families were more likely to have ever been diagnosed with asthma or to still have asthma than children in families that were not poor.
  • Children living in a large metropolitan area are more likely to have asthma

In 2004, there were approximately 20.5 million Americans (6.2 million children) living with asthma1. The highest rates of asthma were seen in the 5-17 year age group 1. What can be confusing about these figures is that it is often reported that the rate of hospitalizations and death due to asthma have actually decreased, possibly indicating that the disease is being managed effectively. This assumption may have been fueled by the 1997 redesign of the National Health Interview Survey (NHIS). After taking into consideration changes to the asthma questions in the redesigned survey, it was determined that asthma rates had not declined and were not significantly different from the mid 1990s. 2

The alleged decrease of asthma, especially among black children, did not support the documented fact that rates of asthma hospitalization and deaths are disproportionately high among poor urban children and continue to remain high 1.

There are many factors that have been associated with the increase in asthma among inner-city or urban residents, primarily children. A scientific review of the Child Health Supplement to the 1988 National Health Interview Survey (NHIS-CH), looked at a variety of demographic variables for independent associations with asthma. It was reported that black children had higher rates of asthma compared to white children. Initially it was thought that race was an independent association for these elevated asthma rates but after accounting for multiple factors; including race, findings suggested that the higher prevalence of asthma among black children is not due to race or to low income but that all children living in an urban setting are at increased risk for asthma. 3 "The driving force in this finding appears to be the increased urbanization of poverty, not race" according to Dr. Robert S. Byrd, director of pediatric outpatient services at U.C. Davis Children's Hospital.

Several factors related to urban living increase asthma prevalence, morbidity, and mortality. These include exposure to air pollution and continued exposure to cockroach, dust mite, mouse, and rat allergens 4. Scientific literature strongly supports that exposure to cockroach allergens can cause asthma in susceptible children and adults in inner-city homes where cockroaches are most common 4, 5. These allergens are proteins found in the cockroach excrement. Children living in many urban or inner city environments have an increased exposure to these allergens compared to children living in more rural environments. The ongoing exposure to cockroach allergens may create an increased immune response and is a known risk factor for asthma 4. Cockroach allergens have been shown to not only increase the risk of asthma attacks but also may increase the risk for developing asthma 6, 7.

A nationwide study on factors that affect asthma in inner-city children suggested that cockroach allergens worsen asthma symptoms more than either dust mite or pet allergens. "Although both dust mite allergen and cockroach allergen exposures were found to be risk factors for the development of positive skin responses, only cockroach allergen exposure, in conjunction with cockroach sensitivity, was associated with increased asthma morbidity." says Rebecca Gruchalla, M.D., associate professor of internal medicine and pediatrics at the University of Texas Southwestern Medical Center and lead author of the study. Although these findings varied based on geographic location, cockroach allergen appears to have a greater effect on asthma morbidity than dust mite or pet allergen. The more prevalent high-rise dwellings in the northeast correlated with significant cockroach antigen exposure, while detached family homes characteristic in the south and northwest had more dust mite sensitization 5. Even with these geographical differences, it was shown that children with cockroach allergies had more asthma symptoms, more school days missed due to asthma and more unscheduled doctor visits for asthma than children in other categories of exposure and sensitization, such as dust mites 5.

It is important to remember that although the research suggests that cockroach allergy can cause asthma, not everyone who is allergic to cockroach allergens has asthma, and vice versa. Researchers believe that asthma is the result of both hereditary as well as environmental factors, and continue to work to unravel the complex relationship between heredity, exposure to indoor allergens, and the development of asthma.

Further research is needed to fully understand the role of cockroach exposure in the prevention and management of childhood asthma in urban and inner city settings. Unfortunately many children do not receive appropriate medications and are only treated for acute episodes. Asthma education programs may help address emotional issues, suggest changes within the home environment to help minimize allergen exposure, and reinforce the role of the patient in the management of their disease.

Reference List

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1. Bloom B DAFG. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2005. 2006. National Center for Health Statistics. Vital Health Stat 10(231). Ref Type: Report

2. Akinbami L. The state of childhood asthma, United States, 1980-2005. Adv Data 2006;(381):1-24.

3. Aligne CA, Auinger P, Byrd RS, Weitzman M. Risk factors for pediatric asthma. Contributions of poverty, race, and urban residence. Am J Respir Crit Care Med 2000; 162(3 Pt 1):873-877.

4. Byrd RS, Joad JP. Urban asthma. Curr Opin Pulm Med 2006; 12(1):68-74.

5. Gruchalla RS, Pongracic J, Plaut M et al. Inner City Asthma Study: relationships among sensitivity, allergen exposure, and asthma morbidity. J Allergy Clin Immunol 2005; 115(3):478-485.

6. Litonjua AA, Carey VJ, Burge HA, Weiss ST, Gold DR. Exposure to cockroach allergen in the home is associated with incident doctor-diagnosed asthma and recurrent wheezing. J Allergy Clin Immunol 2001; 107(1):41-47.

7. Rosenstreich DL, Eggleston P, Kattan M et al. The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma. N Engl J Med 1997; 336(19):1356-1363.

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Text box:

Bloom B, Dey AN, Freeman G. Summary Health Statistics for U.S. Children:

National Health Interview Survey, 2005. National Center for Health Statistics.

Vital Health Stat 10(231). 2006.1

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