Urban Environmental Factors and Childhood Asthma

The purpose of this study is to determine the way environmental factors (like the components of inner-city household dust) affect immune system development and symptoms of asthma in inner city children. The study is divided into three periods, as the subjects age from birth to 10 years old. Each age bracket will explore different objectives and endpoints.

Study Objectives/Hypotheses:

1. Subjects age 0 to 3 years old:

   • Environmental factors in the inner city adversely influence the development of the immune system to promote cytokine dysregulation, allergy, and recurrent wheezing by age 3.
   • Children who have had a viral lower respiratory infection and have developed cytokine dysregulation by age 3 are at increased risk for the development of asthma by age 6.

2. Subjects age 4 to 7 years old:

   • There is a unique pattern of immune development that is driven by specific urban exposures in early life, and this pattern of immune development is characterized by: 1) impairment of antiviral responses and 2) accentuation of Th2-like responses (e.g. cockroach-specific IL-13). The clinical effects of these changes in immune development are frequent virus-induced wheezing and allergic sensitization by 3-4 years of age, and these characteristics synergistically increase the risk of asthma at age 7 years.

3. Subjects age 7 to 10 years old:

   • There are unique combinations of environmental exposures (cockroach allergens, indoor pollutants [ETS and NO2], lack of microbial exposure), and family characteristics (stress, genetic factors related to innate immunity) that synergistically promote asthma onset, persistence, and morbidity in urban neighborhoods. These exposures and characteristics influence immune expression and lung development during critical periods of growth, resulting in specific asthma phenotypes.