Observational Assessment of Baseline Asthma Control in African-American Children
Condition: Asthma
MeSH terms: Asthma
Study type: Observational

Summary: 
      To determine if baseline asthma control influences susceptibility to pollutant-induced health
      effects in African-American children with moderate-to-severe asthma.
    

Detailed description: 
      In the general public, certain sub-populations are at higher risk for adverse health effects
      due to air pollution exposure. Asthmatics have been identified as one such susceptible
      population due to the observed association of elevated air pollution levels and increased
      incidences of acute asthma exacerbations as evidenced by decreased lung function values and
      respiratory symptoms, shortness of breath, emergency department (ED) visits, and
      hospitalizations (6-13). A study conducted by Mar et al (2004) reported that health outcomes
      associated with coarse particulate matter (PM2.5-10) were more notable in children with
      asthma than in adults with asthma (14) and a large epidemiological study of asthmatic
      children in the Northeastern US showed that asthma morbidity on high ozone days was
      consistently highest among children age 6 to 18 years (15). Furthermore, children with
      persistent asthma (requiring daily maintenance medication) were shown to be at increased risk
      of respiratory symptoms and rescue medication use after ambient ozone exposure compared to
      children with mild intermittent asthma (16). Together, these studies demonstrate an
      additional level of susceptibility to air pollution in children compared with adults and in
      children with persistent asthma compared with mild intermittent asthma.

      African-American patients appear to be particularly susceptible to asthma-related
      complications, with rates of asthma-related emergency department visits, hospitalizations,
      and death approximately 2 to 3 times the rates found in Caucasian subjects (17) .
      Furthermore, a higher proportion of African-American asthmatics have poorly-controlled asthma
      compared to non-African-American asthmatics (18). In a recent pediatric study, very poorly
      controlled asthmatics had an increased risk of asthma-related hospitalization, emergency
      department visits, or corticosteroid burst (OR, 6.4; 95% CI, 1.2-34.5) compared with those
      whose asthma was under better control over a 2-year period (19).

      The goal of this panel study is to determine if African-American children with
      poorly-controlled moderate-to-severe persistent asthma are at increased risk for
      cardiopulmonary effects as a result of ambient air pollution exposure compared to age- and
      race-matched well-controlled moderate-to-severe asthmatic children. The primary cohort for
      this panel study will be African-American children between the ages of 12-17 years with
      moderate-to-severe asthma (divided between the study populations of poorly-controlled asthma
      and well-controlled asthma). Since this study is exclusively focused on an African-American
      population, it is not designed to address the effect of race/ethnicity on baseline asthma
      control. Volunteers will be recruited primarily from the UNC Pediatric Pulmonary clinic and
      the UNC Allergy/Immunology clinic located at Rex Hospital in Raleigh, NC in which Dr.
      Hernandez is an attending physician. These volunteers are well-characterized asthmatics
      followed regularly by a pediatric pulmonologist (Dr. Ceila Loughlin) and by a pediatric
      allergist (Dr. Michelle Hernandez) at the Rex location. In order to ensure that the two
      cohorts experience equivalent daily exposures to ambient air pollutants, the study population
      will be recruited from a defined geographical region within a reasonable driving distance of
      the Rex Hospital and in relative proximity to the state-operated monitoring station for
      ambient air pollutants.

      Establishing a relationship between asthma control and adverse health outcomes in response to
      air pollution exposure will provide health care providers and parents of children with
      moderate-to-severe asthma the information necessary to take proactive action on high air
      pollution days as they are communicated to the public through color-coded days based on the
      National Ambient Air Quality Standards (NAAQS) established by the EPA. If asthma control is
      determined in this study to be a risk factor for susceptibility, future work will be directed
      toward establishing the mechanism underlying the susceptibility which may then lead to the
      potential design of new therapies or intervention strategies.
    

Observational model: Ecologic or Community
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        We will enroll a maximum of 60 African-American children with moderate-to-severe persistent
        asthma in which half of the cohort will have well-controlled asthma and the other half will
        have poorly-controlled asthma (defined by NHLBI guidelines). Participants will be of both
        genders, ages 12-17 years old, and live within a convenient driving distance from the study
        site located within the UNC Pediatric Pulmonary and UNC Pediatric Allergy and Immunology
        Subspecialty clinics at Rex Hospital located in Raleigh, NC.
      
Keywords: African American; Asthma