OVERVIEW AND DISPARITIES
Asthma is a chronic respiratory disease causing transient episodic attacks of wheezing, coughing, and shortness of breath. Mild asthma has minimal functional consequences to daily life and activity, but severe asthma is characterized by frequent attacks and symptoms that can cause sleep disruption, necessitate urgent medical care, lead to hospitalization, and, in rare cases, death. Poor urban minority youth experience disproportionately high rates of severe asthma and are dramatically harmed by this disease. Asthma adversely affects quality of life for youth and their families and is associated with inefficient and ineffective use of health care resources. Asthma undermines the mental-emotional and physical health of youth and has harmful effects on educational outcomes through multiple pathways.
Asthma is thought to be the result of complex interactions between genetic and environmental factors.1–5 Its etiology is not clearly understood, thus populationwide approaches to primary prevention are not yet feasible.6 Many cases of mild or moderate asthma resolve with age, but, to the extent that the disease persists and is severe, more harmful long-term consequences accrue.1–3,5 This fact underscores the importance of minimizing poorly controlled disease among youth. Effective educational and public health approaches include controlling symptoms through medications that reduce susceptibility to asthma attacks and minimization of exposure to environmental allergens and irritants that may cause and exacerbate symptoms.6
The 2006 National Health Interview Survey indicated that 9.9 million youth under 18 years old (14%) had ever been diagnosed with asthma and 6.8 million (9%) still had asthma.7 Compared with girls, boys were more than 45% more likely to have ever been diagnosed with asthma (11% vs 16%) and more than 35% more likely to still have asthma (8% vs 11%).7 Both lifetime and current asthma prevalence disproportionately affect non-Hispanic Black youth, particularly those from poor families. Compared with youth under 18 years old not in poor families, youth in poor families had prevalence rates that were almost 40% higher for ever having asthma (13% vs 18%) and almost 45% higher for current asthma (9% vs 13%).7 Urban minority youth not only experience higher prevalence of lifetime and current asthma, but also worse health-related consequences, both of which adversely affect educational outcomes.
The following data describe average annual numbers and/or rates of asthma during 2001–2003 for youth between the ages of 5 and 14.6 There were 3,878,000 youth with current reported asthma and 111 deaths. Average annual prevalence estimates were approximately 45% higher for Black versus White children (12.8% vs 8.8%) (Figure 1), as were average annual estimates of asthma attacks (8.4% vs 5.8%). The estimated annual rate of emergency department visits with asthma as the primary diagnosis was 3 times greater for Black versus White children (18.3% vs 6.1%). Average annual prevalence estimates for children of Puerto Rican descent were 21.5%, compared with 5.4% for children of Mexican descent (Figure 1). Reasons for higher prevalence of asthma among children of Puerto Rican versus Mexican decent6,8,9 are not well understood,10 but the discrepancy has implications for directing limited resources to the populations with the greatest needs.
The most recent estimates from a nationwide probability sample of high school students11 indicate that 20.3% had ever been told they had asthma. Lifetime asthma prevalence estimates were more than 22% higher for Black (24.0%) than White (19.6%) students. Lifetime asthma prevalence for Hispanic students (18.5%) must be interpreted with caution due to the extreme heterogeneity of asthma among Hispanic students.6,8,9 Almost 11% of high school students reported current asthma, and the prevalence rates of current asthma were 40% higher for Black (14.7%) than White (10.5%) students. The rate for Hispanic students was 9.5%.
If national prevalence estimates indicate a very substantial magnitude of asthma, statewide and local prevalence estimates among urban minority youth have been even higher. The most recent data indicate that lifetime asthma prevalence among high school students across 34 participating states ranged from 15.4% to 28.7%. Estimates of current asthma ranged from 8.4% to 14.2%. Surveys in selected local areas demonstrate considerable variation in current asthma prevalence: from 6.8% in Houston to 19.9% in Baltimore.11 In Detroit, 1 study in 14 elementary schools identified approximately 25% of children from approximately 4600 participating families as having asthma,12 another conducted with 35 Head Start centers found probable asthma reported by 30% of parents responding.13 A study of children of Puerto Rican descent from samples collected in 2 urban areas of Puerto Rico and in the South Bronx estimated that 38.6% and 35.3%, respectively, had current asthma.8 A statewide surveillance project conducted in Massachusetts, which included one half of K-8 schools (n = 958 schools), found that prevalence based on nurse reports was, on average, 9.2% across all participating schools, but as high as 30.8% in individual schools.14 A survey of more than 8000 middle school students in Oakland, CA, indicated that 17.5% had active asthma.15 Additional studies could be outlined. The evidence that poor urban minority children are disproportionately harmed by uncontrolled asthma is not controversial.
Poor urban minority youth not only have higher rates of asthma and more severe forms of the disease, but are much less likely to receive contiguous high-quality medical care and to consistently use appropriate, efficacious medications. They are also more likely to be exposed to noxious environmental “triggers.” Consequently, they are more likely to experience severe asthma that adversely affects their quality of life, including their motivation and ability to learn in school.
Current knowledge exists to control asthma effectively and to minimize its harmful consequences. The 3 main asthma control methods are (1) access to contiguous high-quality medical care, (2) medications to control clinical sequelae (eg, asthma attacks), and (3) avoidance or minimization of environmental triggers. Poor urban minority youth experience extreme and consequential disparities with respect to all 3 of these highly effective secondary prevention methods.
Emergency department visits for asthma increased dramatically from 1980 (79.1/10,000) to 2004 (155.1/10,000), with a more than 4-fold disparity in emergency department use between Black (195.0/10,000) and White (43.6/10,000) children.6 Conversely, in 2001–2003, the estimated average rate (per 100 persons with current asthma) of physician office visits was almost 150% higher for White (74.9) than Black (30.2) children.6 Intervention programs have sought to reduce asthma-related emergency department visits because of cost and because, while emergency care addresses the acute problem (ie, an asthma attack), it does not tend to foster continuity of medical care or effective disease management.
Gaps in health insurance coverage affect a significant proportion of children in the United States and limit their access to quality medical care.16,17 This is particularly a problem for poor urban minority youth, in general,18–21 and youth with asthma, in particular.19,22–25 Given that access to consistent and high-quality medical care can help prevent morbidity from asthma,26–29 disparities in access are likely to be one of several key factors accounting for disparities in asthma morbidity.17,19,30 Medical access disparities are evidenced by greater dependence on emergency departments, as opposed to consistent primary care,31 by more severe acute exacerbations,32 and by inappropriate overuse of medications.24
Adherence to asthma medications (eg, budesonide inhalation suspensions) can prevent asthma morbidity.27,31,33–37 Appropriate use of inhaled corticosteroids has been associated with improved chronic airway inflammation and course of the disease,34 decreased use of emergency departments,31,33,35,37 and decreased hospitalization.27,31,33,37 But adherence to effective medications has been found to be much lower among poor urban minority youth.24,30,31,38,39 Medication adherence problems have been found to affect both younger26,40 and older41 children, and to disproportionately affect Black and Latino children, independent of income.42 In some inner-city families, children rather than parents, are responsible for medication adherence.43 Nonadherence to medication has been associated with more frequent asthma exacerbations, emergency department visits, and hospitalization.31,40
Poor urban minority youth have high levels of exposure to indoor pollutants (eg, environmental tobacco smoke) and allergens (eg, in the northeast, cockroach allergens).44,45 They also exhibit heightened sensitivity to these allergens.46 The combination of exposure and sensitization is thought to be one of several key causes of asthma morbidity.47 In the Inner City Asthma Study, compared with children who were not exposed or sensitized to cockroach allergen, children who were both exposed and sensitized experienced more days of symptoms and missed more school. Once sensitized, even low levels of exposure can trigger an allergic response,48 underscoring the value of preventing sensitization and avoiding exposure to allergens among those already sensitized. Outdoor pollutants in the inner city (eg, diesel exhaust particulates) may interact with allergens to exacerbate allergic reactions among susceptible youth, thereby increasing the extent of morbidity.49,50
There are regional variations in the nature and extent of indoor allergen exposure in the United States. In northeastern inner cities (eg, New York and Boston), cockroach allergen exposure appears to influence asthma morbidity more than pet allergens or dust mites. In the south and northwest, there are higher levels of exposure and sensitivity to dust mites. Inner-city communities are vulnerable to specific kinds of exposures at high concentration levels.51 Type of dwelling (eg, public housing apartments) and specific features of the household have also been found to be associated with the presence of particular kinds of allergens.52 These local variations in the kinds of allergen exposure and sensitivity have important implications for planning prevention programs. Tailoring interventions to the relevant allergens and pollutants of specific populations will likely have a strong influence on their effectiveness.53
The home is a primary exposure source of indoor allergens and pollutants.49,53 For youth, the school environment is also important.54,55 In a Minneapolis study of 2 elementary schools serving poor urban minority youth, the school environment was found to be an important source of fungi and cat allergen.56 A southeast Texas study of 60 urban elementary schools (385 rooms) included extensive environmental assessment in 20 schools. Cockroach allergen was found in all of the schools and the observed levels were above recommended limits in 10% of the rooms. Mold spores exceeded recommended limits in more than half of the classrooms.57 In the most recent nationwide School Health Policies and Programs Study, approximately one third of districts and approximately one half of schools had an indoor air quality program, approximately one third had a bus idling reduction program, approximately one quarter of the states required schools to adhere to a pest management program.58 These data illustrate both positive current initiatives and the need for increased environmentally relevant policies and programs. (It should be noted that respiratory infections and exercise in cold weather may also trigger symptoms.)
In addition to the 3 risk factors outlined above, poor urban minority youth often have other risk factors that affect moderate to severe persistent asthma morbidity. These include household and outdoor environmental exposures, behavioral or emotional concerns, lack of parental support regarding medication, poor medication adherence, and poor medical care43 as well as multiple risks of a psychosocial or sociocultural nature.59,60 In addition, lower levels of parental literacy have been associated with greater use of emergency departments, hospitalization, rescue medications and school absenteeism; parents had less knowledge about the disease and their children were more likely to have more severe persistent asthma.61 Although the disproportionate prevalence of asthma among poor urban minority populations is of great concern, of even greater concern are the disparities in asthma severity, emergency department utilization and hospitalization, and behavioral and environmental factors.62 These disparities all have consequences for quality of life in general and educational outcomes in particular.