December 12th, 2017
More than 20 million people in the United States are estimated to have asthma (CDC, 2003).Among children, it is the most common chronic illness (NAS, 2000).A substantial body of research, including population-based studies of school-aged children and young adults, indicates that the prevalence and severity of asthma have increased dramatically over the last several decades in the United States and many other parts of the world (CDC, 1998b; Carter and Platts-Mills, 1998; Platts-Mills, 1998). Furthermore, in the U.S., rates of increase of asthma are disproportionately high among children andAfricanAmericans (Eggleston, 2000).Although research has suggested that a large portion of the observed racial/ethnic differences in asthma prevalence is explained by factors related to income and level of education (Litonjua et al., 1999), residence in an urban area has been implicated as an important risk factor for all children (Aligne et al., 2000). Researchers have also found marked differences in the types of asthma triggers found in homes in inner-city areas compared to suburban or rural areas (Kitch, 2000; Kattan et al., 1997). However, substantial differences in the overall burden of agents which exacerbate asthma have not necessarily been established (Kitch, 2000).