Etiology and pathogenesis of airway disease in children and adults from rural communities.

Asthma is the most common chronic disease of childhood and affects nearly 5 million children. The prevalence and severity of childhood asthma have continued to increase over the past decade despite major advances in the recognition and treatment of this condition. A comparison of urban and rural children suggests that the etiology of airway disease is multifactorial and that unique exposures and genetic factors contribute to the development of asthma in both settings. The most important environmental exposure that distinguishes the rural environment and is known to cause asthma is the organic dusts. However, animal-derived proteins, common allergens, and low concentrations of irritants also contribute to the development of airway disease in children and adults living in rural communities. A fundamental unanswered question regarding asthma is why only a minority of children who wheeze at an early age develop persistent airway disease that continues throughout their life. Although genetic factors are important in the development of asthma, recurrent airway inflammation, presumably mediated by environmental exposures, may result in persistent airway hyperresponsiveness and the development of chronic airway disease. Increasing evidence indicates that control of the acute inflammatory response substantially improves airflow and reduces chronic airway remodeling. Reducing exposure to agricultural dusts and treatment with anti-inflammatory medication is indicated in most cases of childhood asthma. In addition, children with asthma from rural (in comparison to urban) America face multiple barriers that adversely affect their health e.g., more poverty, geographic barriers to health care, less health insurance, and poorer access to health care providers. These unique problems must be considered in developing interventions that effectively reduce the morbidity and mortality of asthma in children from rural communities.