Rural Asthma: Current Understanding of Prevalence, Patterns, and Interventions for Children and Adolescents

Abstract

Purpose of Review

Asthma is the most common chronic illness of children and adolescents in the USA. While asthma has been understood to disproportionately affect urban dwellers, recent investigations have revealed rural pediatric asthma prevalence to be very similar to urban and to be more closely correlated with socioeconomic and environmental factors than geographic location or population density.

Recent Findings

Rural children experience factors unique to location that impact asthma development and outcomes, including housing quality, cigarette smoke exposure, and small/large-scale farming. Additionally, there are challenging barriers to appropriate asthma care that frequently are more severe for those living in rural areas, including insurance status, lack of primary care providers and pulmonary specialists, knowledge deficits (both patient and provider), and a lack of culturally tailored asthma interventions.

Summary

Interventions designed to address rural pediatric asthma disparities are more likely to be successful when targeted to specific challenges, such as the use of school-based services or telemedicine to mitigate asthma care access issues. Continued research on understanding the complex interaction of specific rural environmental factors with host factors can inform future interventions designed to mitigate asthma disparities.

Introduction

Asthma is the most common chronic illness of children and adolescents in the USA [1]. It is an inflammatory disease of the airways characterized by bronchial hyperresponsiveness, mucosal edema, and airflow restriction. Clinically, asthma is manifest by episodic chest tightness, shortness of breath, cough, and wheeze. These symptoms are usually reversible with appropriate medical intervention. Symptomatology is highly variable and may differ not only from patient to patient, but exacerbation to exacerbation in the same patient. While asthma is frequently referred to as a disease, it appears to be a symptom complex caused by various combinations and interactions between host factors (e.g., genetics, sex, obesity) and environmental exposures (e.g., viral respiratory infections, allergens, air pollutants) resulting in phenotypic heterogeneity and different patterns of airway remodeling [2, 3]. Asthma is more common in children but can affect individuals of all ages.

Pediatric asthma (ages 0–17 years) [4] has previously been understood to disproportionately affect urban dwellers (see Milligan, Matsui, and Sharma for a comprehensive overview of asthma in urban children) [5]. However, recent investigations have revealed rural pediatric asthma prevalence to be very similar to suburban and urban [6••, 7••, 8••]. The distribution appears to be more closely correlated with socioeconomic and environmental factors than geographic location or population density [9, 10]. A refocus on these factors—race/ethnicity, socioeconomic status, indoor smoking, pest, and other environmental exposures—has demonstrated a more variable distribution pattern [9].

For rural children, adolescents, and their families, asthma is an important health problem with management challenges requiring locally appropriate interventions. In this review, we explore the definition of rural areas in the USA and the intersection of rurality with other demographic factors on asthma prevalence and follow with an overview of unique rural asthma triggers, barriers to healthcare access, and rurally tailored interventions with positive outcomes. We conclude with recommendations for future research.

Rurality and Demographics

Variations in what is meant by the term “rural” make it challenging to compare research that considers location in the evaluation of asthma (or any other disease process, for that matter) [11]. Moreover, how the term is defined influences policy making and resource allocation, which in turn impacts individuals and has the potential to affect healthcare outcomes. Built on geographic units such as counties, zip codes, and census tracts, in general, rural is conceptualized as everything that is not urban or suburban; specific definitions are developed by specific agencies for specific usage, such as funding for healthcare clinics in underserved locations (see Table 1 for commonly used US federal definitions). Narrowly targeted definitions of rural designed to benefit specific populations may inadvertently exclude eligible program recipients [12]. Conversely, broader definitions may cause budgetary strain by including areas with less need. In most healthcare literature, rural is an area distant from any population center of 50,000 or more inhabitants.

Table 1.

US federal definitions of rural

Organization	Definition
US Census Bureau	Rural encompasses all population, housing, and territory not included within an urban area [13]. Urban areas include urbanized areas (50,000 people or more) and urban clusters (2500–50,000 people) [14].
Office of Management and Budget (OMB)	Rural includes all counties not part of a metropolitan statistical area (MSA), one of three core-based statistical areas. An MSA is a geographical entity associated with at least one urbanized area of 50,000 people, as well as adjacent counties with a high degree of social and economic integration with the urban area. Counties that are designated as micropolitan (10,000 to 50,000 people) or non-metropolitan are considered rural [15].
Federal Office of Rural Health Policy	All non-metropolitan areas are considered rural, as well as areas determined to be rural by Rural-Urban Commuting Area (RUCA) codes [16]. RUCA codes are sub-county census tracts representing urbanization, population density, and daily commuting [17].

Using the OMB definition, 14 % of US residents, or approximately 46.2 million, live in non-metropolitan counties [18]. Of this cohort, over 42% live in the South (Delaware, District of Columbia, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia, Alabama, Kentucky, Mississippi, Tennessee, Arkansas, Louisiana, Oklahoma, and Texas) [19, 20]. In general, poverty rates are higher in rural areas; these areas are also significantly more likely to be persistently poor, a term indicating counties in which 20% or more of the population has been living in poverty for 30 years [19]. Eighty-five percent of the 353 persistently poor counties are non-metro [19]. Poverty rates vary widely within and between regions. For example, the largest poverty gap (a measure of poverty intensity) between non-metro/metro areas is found in the South [19]. The 2010–2014 poverty rate in the northeast non-metro area was 13.9%; the poverty rate in the non-metro South during that same period was 21.8% [19].

Racial/ethnic composition of rural communities also differs by region of the USA. Most rural areas are predominantly white, with African American-predominant communities found mostly in the South, Hispanic-predominant communities in the Southwest, and Native American communities in the Midwest/West/Alaska/Hawaii regions [21].

Rurality and Pediatric Asthma Prevalence

One of the challenges in understanding pediatric asthma prevalence lies in the way that data are collected and presented. Typically, asthma is characterized by variables such as location, gender, race/ethnicity, socio-economic status, and change over time; group comparisons facilitate our understanding of asthma burden. For example, national data showed an increasing trend in pediatric asthma prevalence from 2001 to 2009, and after plateauing, the rate began to significantly decrease to 8.3% (SE 0.3%) in 2013 [4]. Over this same period, prevalence rates increased for poor and near-poor, non-Hispanic black, and Mexican-American children and adolescents, as well as those living in the South and Midwest [4]. The increases in asthma prevalence noted in these specific demographic groups, especially for non-Hispanic blacks, accounted for the increase in asthma prevalence disparities observed from 2001 to 2012, although this trend appears to be plateauing as well [4].

However, variables do not occur in isolation. Teasing out the unique intersections of factors associated with asthma development with rurality is challenging and may contribute to previous perceptions of a rural/urban dichotomy in asthma prevalence. Studies are beginning to demonstrate rural pediatric asthma prevalence to be similar to urban (see Table 2 for selected studies comparing rural and urban pediatric asthma prevalence).

Table 2.

2010–2016 selected studies, urban vs. rural asthma prevalence

Author (publication year)	Setting/sample	Urban (%)	Rural (%)	Notes
Fedeleetal. (2016) [8••]	Florida Youth Tobacco Survey administered to public middle and high school students	Middle, 12.1; high, 10.7	Middle, 12.9; high 11.2	Findings suggested racial/ethnic disparities in rural communities; rural AA students were more likely to report a diagnosis of asthma and higher rates of ED/urgent care use as compared with non-Hispanic white peers.
Ownbyetal. (2015) [7••]	6994 African American youth in Detroit compared with 1514 AA youth in rural Georgia	15	13.7	The prevalence of undiagnosed asthma in AAyouth was also similar between groups (8.0% in Detroit and 7.5% in Georgia),
Pesek et al. (2010) [22••]	Urban and rural school districts in Arkansas	20	19	While provider-diagnosed asthma rates were similar, rural children were more likely to receive a diagnosis of chronic bronchitis (7 vs. 2%, P < .001) and suffer increased asthma morbidity, including recurrent trouble breathing (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.5–2.2), recurrent cough (OR, 2.2; 95% CI, 1.9–2.6), recurrent chest tightness (OR, 1.8; 95% CI, 1.5–2.2), and repeated episodes of bronchitis (OR, 2.2; 95% CI, 1.7–2.8) during the preceding 2 years.
Valet etal. (2011) [6••]	117,080 children continuously enrolled in Tennessee Medicaid from birth through the sixth year of life.	11	13	Rural children had increased asthma prevalence, were more likely to utilize outpatient asthma care, and less likely to use inhaled corticosteroids as compared to their urban counterparts.

The categories of poverty, racial/ethnic minority status, and healthcare access barriers, well-known to be associated with the higher risk of asthma, sub-optimal management, and poorer outcomes, are suffered by both rural and urban children alike. However, the specific factors experienced by children within those categories warrant further exploration.

Unique Locational Factors Impacting Rural Pediatric Asthma

In addition to the general asthma risk factors discussed in the previous section, there are unique factors commonly experienced by rural-dwelling children and adolescents with asthma. These include micro and macro-environmental exposures and barriers to accessing appropriate asthma care.

Micro-Environmental Exposures and Individual Factors

The micro-environment consists of the child’s immediate environment, which includes specific asthma triggers inherent to that setting [23]. For rural children and adolescents, housing factors and cigarette smoking are particularly problematic.

Housing

The quality of a child’s living space is directly related to asthma outcomes—environmental control measures (e.g., mold and pest removal, air filtration, carpet removal) are part of a comprehensive approach to asthma management [2]. More than two thirds of young rural families (head of household younger than age 35) live in rental housing [24]. Rural rental properties are more likely to be single-family/small multi-family dwellings, older (35% were built before 1960), and substandard [24]. Coupled with the dearth of rural rental units and the increased likelihood of limited economic resources, families with children may have more difficulty finding affordable quality housing options. Not only do these conditions increase the probability of living with asthma triggers, but renters have less ability to mitigate these environmental exposures.

Urban children are more likely to live in multi-unit housing, which is associated with cockroach, rodent, and dust mite allergen exposure; those with asthma often demonstrate sensitization to these aeroallergens, especially children hospitalized for asthma exacerbations [25]. However, rural children with asthma also demonstrate exposure and sensitization, and it is unclear if this sensitization and subsequent asthma development is dose-dependent. One study in the rural Arkansas Delta found that even though the majority of child participants with asthma lived in single-family dwellings, most of the homes had cockroach and mouse allergens, albeit at lower concentrations than seen in urban homes [26].

Indoor air quality is an additional issue for rural children and adolescents. Children living in rural areas are more likely to reside in housing with wood-burning heat [27]. Older homes are more likely to have issues with leaking; damp environments encourage mold growth and are associated with an increased incidence of current asthma [27, 28•].

Smoking

Not only is tobacco smoking prevalence higher amongst rural inhabitants, but rural smokers are more likely to smoke 15 or more cigarettes daily [29]. Rural children are more likely to live in a home with a smoker (35 vs. 24% living in urban homes) and to be exposed to secondhand smoke in cars [30]; this exposure significantly increases ED utilization, and more than doubles the odds of hospitalization for children with asthma [31]. Rural adolescents begin smoking earlier than their urban peers and are more likely to smoke daily [30]. These adolescents are also more likely to be targeted by tobacco marketing and less likely to be exposed to anti-smoking messaging [30, 32].

Macro-Environmental Exposures

Outside air quality in rural areas is, in general, better than in urban areas, and children may experience less exposure to pollutants associated with worse asthma outcomes (such as diesel exhaust). Nevertheless, there are specific macro-environmental factors that both positively and negatively impact asthma outcomes for rural-dwelling children and adolescents.

Small Farms

With the rise of agribusiness and decline in family farming, the perception that rural children live on farms is increasingly erroneous. Farm and ranching families make up only 2% of the US population [33], and this number will likely continue to decline as the average age of the farmer (58 years in 2012) continues to climb [34]. Even so, numerous studies have demonstrated a protective benefit of small farm living on the development of asthma by rural children and adolescents [35]. Explanations for this include exposure to dust and environmental microbial agents [36–38] and increased diversity in the nasal microbiota [39]. As the variables associated with small farm living are highly correlated, it is difficult to disentangle individual variable effects. It is likely that there is an interactive, complex effect between specific genes and the environment resulting in a decreased risk of developing asthma or a protective effect on sensitization and subsequent wheeze [40]. For example, exposure to a farm environment in early childhood influences methylation patterns in asthma and IgE-related genes in peripheral blood cells [41]. Research focusing on specific environmental exposures, rather than simply farm residential status, is increasing understanding on the asthma-protective factors associated with farm living. These include living on a grain farm [42], riding horses [42], exposure to animal pens and sheds [42, 43], and consumption of unprocessed cow’s milk containing higher levels of ω−3 polyunsaturated fatty acids [44, 45].

Large-Scale Farms

However, living on or near large farms does not have the same protective benefit. Children and adolescents living in rural areas are exposed to the environmental effects of a variety of commercial animal feeding operations (CAFOs) and the associated large-scale animal waste [46]. CAFOs tend to be concentrated in regional “hotspots,” leading to unique community impacts depending on the type of facility. For example, swine CAFOs are concentrated in the central USA, cattle in the central to western USA, and chicken in the southeast. Close proximity to swine CAFOs increases exposure to airborne by-products of industrial hog farming, including noxious gases such as ammonia and hydrogen sulfide [47]; those with asthma are more likely to have decrements in peak flow FEV₁ in post-exposure days [48].

Barriers to Appropriate Asthma Care in Rural Areas

Barriers to accessing appropriate asthma care affects outcomes and is a key contributor to disparities suffered by certain populations. For rural children and adolescents, unique barriers include insurance status, unavailability of primary care providers and pulmonary specialists, knowledge deficits (both patient and provider), and lack of culturally tailored asthma interventions.

Insurance

While the uninsurance rate has declined significantly across all population groups since the implementation of the Affordable Care Act (ACA), rural residents are still more likely to be uninsured than urban residents (14.4 vs. 10.9% in 2015) [49] and have more limited choices of insurance providers when compared to those living in metropolitan areas [50]. Rural residents are more likely to be covered by Medicaid, a state-administered health insurance program for low-income children, pregnant women, families, and those with disabilities. They are also more likely to fall into a “coverage gap” in which their family’s income is too high to qualify for Medicaid, but too low to qualify for ACA marketplace subsidies, especially if they live in states that opted out of Medicaid expansion [51].

Accessibility

Primary care physicians are less likely to practice in rural areas, with an average of 68 per 100,000 rural residents as compared to 84 per 100,000 urban residents [52]. Rural patients also have less access to specialty care. For example, children with asthma residing in Georgia frequently travel over 15 mi for primary care and between 30 and 50 mi to see a specialist [53]. Access barriers, coupled with the costs and risks associated with travel, are associated with increased ED usage and hospitalizations and more frequent exacerbations.

Knowledge Deficits

Asthma knowledge deficits on the part of children and their families are commonly seen in both urban and rural populations and lead to sub-optimal management and poorer outcomes. However, rural healthcare providers may be less aware of current National Heart, Lung, and Blood Institute (NHLBI) pediatric asthma management guidelines which can contribute to these poorer outcomes. Rural children with persistent or uncontrolled asthma are more likely to overuse rescue medications [54••], underuse inhaled corticosteroids [6••], or receive a prescription for leukotriene receptor antagonist monotherapy (i.e., Singulair®), all non-preferred treatment regimens leading to increases in ED visits for asthma exacerbations [55•]. Spirometry performed in primary care clinics rarely meets American Thoracic Society/European Respiratory Society quality criteria [56]. As rural patients are significantly more likely to be managed by primary care providers, they are at greater risk for misdiagnosis.

Cultural

Rural ethnic/racial minority children suffer poorer asthma-related quality of life than their non-Hispanic white peers [57], in part due to lower health literacy [58]. Research that considers local contexts of environmental exposures and the adaptation of asthma educational materials and programs for specific rural populations (e.g., First Nations and Inuit people, African Americans, Hispanics, migrant farmworkers) have the potential to improve uptake of knowledge and appropriate asthma practices, such as reducing indoor asthma triggers in migrant farmworker housing [59–62].

Target Interventions with Improved Asthma Outcomes

Multi-Component Interventions

While individual interventions such as educational interventions have been promising, those that include multi-components demonstrate more robust results. For example, a program targeting 20 rural western North Carolina counties and the Eastern Band Cherokee Indian Reservation included individual- and community-level asthma education and environmental assessments. After 2 years, program participants demonstrated improvements in lung function and a significant decrease in emergency department visits (158 to 4), hospitalizations (62 to 1), and average school day absences (17 to 8.8 days) [63••]. Similar multi-component programs have also demonstrated increases in controller medicine and reduction in self-reported asthma symptoms, at low cost [64].

Provider Education

Interventions to improve patient asthma outcomes by increasing healthcare provider knowledge base are promising. As rural providers have similar access barriers as their patients, interventions designed with transportation and costs in mind have demonstrated increased acceptability and success. Targeted to clinicians working on primary care teams and school nurses, successful programs have focused on improving the ability to provide appropriate asthma education, including assessment of asthma control and inhaler technique, asthma action plan development, provision of appropriate controller medication prescriptions, and follow-up appointments [65, 66].

School-Based Interventions

School-based programs and/or the incorporation of nursing services in the management of asthma is increasingly part of interventions for rural adolescent and children [67]. These include asthma education delivered via in-school asthma classes or asthma day camps [68]. Interventions focusing on self-management behaviors beyond simple medication compliance have the most potential for improving asthma outcomes in rural children [69].

Telemedicine

Interventions addressing access to asthma specialists by rural children and adolescents have also demonstrated promise in improving asthma outcomes. In particular, management via telemedicine has shown equivalent or improved asthma outcomes for rural children and adolescents as compared to in-person specialty visits, with high patient acceptability [70•].

Conclusion

Pediatric asthma is a costly chronic disease, with recent estimates placing direct and indirect costs at over $3000 per patient annually [71] and over $56 billion total in the USA [72]. Medications and hospitalizations are the most significant direct cost drivers; work and school days missed due to asthma exacerbations account for the majority of indirect costs [73]. Asthma is the most common cause of school days missed—10.5 million days/year—with almost 60% of children with one asthma exacerbation annually missing at least 1 day of school [74].

Decreasing these personal and societal costs requires evidence-based interventions and strategies, but solutions cannot be one-size-fits-all. While environmental and socio-economic issues associated with asthma are not necessarily location-dependent, there are specific factors more commonly encountered when caring for rural children and adolescents with asthma. These include micro- and macro-environmental exposures that can be challenging to address, especially in light of the limited resources and access barriers commonly experienced by rural children and their families. However, rural communities are not homogeneous. Each rural area may have a unique mix of challenges and strengths that should be accounted for when exploring ways to improve the state of asthma for their youngest community members. Researcher and provider engagement with local community members in assessing community needs and experiences may facilitate the identification of specific local environmental, socio-economic, and host factors associated with pediatric asthma. Interventions using existing services (such as school-based nursing services) and technology (such as tele-medicine) are proving to be beneficial, cost-effective, and sustainable. The scalability of these promising, tailored strategies will require careful consideration of how healthcare policies and legislation can facilitate rural pediatric asthma management and mitigate asthma outcome disparities and costs.