Inner city asthma, a pressing public health concern, illustrates the complexity of developing research evidence to reduce morbidity and mortality for a disease that is affected by a broad range of urban microenvironments. The prevalence and severity of childhood asthma have increased in the last 20 years, and the greatest increase has been seen among children and young adults living in U.S. inner cities (Crain, et al., 1994; Eggleston, et al., 1999). Despite deepening insight into the pathophysiology of asthma and a better understanding of chronic management of the disease, asthma remains the leading cause of chronic illness among children. According to the US National Health Interview Survey, nine million U.S. children under 18 years of age (12%) have ever been diagnosed with asthma. More than 4 million children (6%) had an asthma attack in the previous year (Dey, et al., 2004). Children in poor families (16%) were more likely to have ever been diagnosed with asthma than children in families that were not poor (11%) (Dey, et al., 2004). Among poor inner-city children, asthma is more severe and less likely to be appropriately managed relative to asthma in more affluent communities. In addition to having the highest asthma prevalence, inner-city children have the highest asthma hospitalization rates in the country (Centers for Disease Control and Prevention (CDC), 1997). Asthmatic children living in urban environments have a higher frequency of attacks and more severe attacks relative to their suburban and rural dwelling counterparts (Graham, 2004). The burden of asthma is particularly prominent among minority children. Among black and latino children living in the inner city, as many as 25% suffer from asthma (Webber, et al., 2002). As a consequence of the greater burden of asthma, increased severity, and poor management, mortality from asthma is as much as three times higher in minorities (Perera, et al., 2002; Weiss, et al., 1993).
As researchers have approached inner-city asthma, they have faced numerous challenging questions: What are the environmental and genetic determinants of susceptibility to asthma? What environmental agents cause asthma among those who are susceptible? For asthmatics, what agents exacerbate the disease and provoke attacks and where do exposures to these agents take place? What are their sources and what social and neighborhood factors determine exposure? What social-environmental factors mediate access to health care and compliance with disease management strategies? What interventions are effective in modifying the burden of disease in urban populations? These questions have set an extensive research agenda that has now been pursued for over a decade, through both specific initiatives such as the Inner City Asthma Studies and through investigator-initiated studies (Gergen, et al., 1999; Mitchell, et al., 1997; Wade, et al., 1997). The full spectrum of designs has been used for investigating inner-city asthma.
Environmental exposures to allergens and air pollutants affect a susceptible child, resulting in respiratory morbidity. In addition to, and perhaps interacting with, genetic susceptibility factors are characteristics of urban life that increase vulnerability to disease, including psychosocial stress, high smoking rates, inappropriate medication use, inadequate resources, and poor access to quality health care.
The microenvironmental model sets a useful framework for considering both research and intervention. For children with asthma, the home is likely the single most important environment for assessing exposure; as school-age children spend most of their time indoors at home (68%). School is the next most important microenvironment, at 15% of time on average. Inner city children spend greater time in their homes than their non-urban dwelling counterparts (Chapin,Jr., 1974). Many environmental factors have been associated with exacerbation of asthma and some may also hasten the onset of asthma. Table 4 summarizes some of the many biological and chemical agents found in homes that may cause or exacerbate asthma. In urban environments, secondhand smoke, biological agents, and combustion emissions are prevalent and often at high concentrations.
Table 4. Indoor Biological and Chemical Agents That May Cause or Exacerbate Asthma
Sufficient Evidence of a Causal Relationship
Cat ETS (in preschool-aged children)*
Cockroach* House Dust Mite*
Cause House Dust Mite*
Sufficient Evidence of an Association
Fungi or molds* Rhinovirus
Respiratory Syncytial Virus (RSV) Cockroach (in preschool-aged children)*
Limited or Suggestive Evidence of an Association Exacerbate
Domestic birds Mycoplasma pneumoniae Chlamydia pneumoniae Respiratory Syncytial Virus (RSV)
Inadequate or Insufficient Evidence to Determine Whether an Association Exists Exacerbate Rodents*
Chlamydia trachomatis Endotoxins Houseplants
Pollen exposure indoors e insects other than cockroaches
Cause Cat Dog
Domestic birds Rodents*
Cockroach (except in preschool-aged children) Endotoxins Fungi or molds* Chlamydia pneumoniae Chlamydia trachomatis Mycoplasma pneumoniae Houseplants Pollen
Was this article helpful?
Do You Suffer From ASTHMA Chronic asthma is a paralyzing, suffocating and socially isolating condition that can cause anxiety that can trigger even more attacks. Before you know it you are caught in a vicious cycle Put an end to the dependence on inhalers, buying expensive prescription drugs and avoidance of allergenic situations and animals. Get control of your life again and Deal With Asthma Naturally