Asthma is the most common chronic disease that appears in childhood, affecting approximately 8% of children in the United States (US). [1] 5.9% of Hispanic youth, 5.5% of non-Hispanic white youth, and 11.6% of Black non-Hispanic youth, 3.3% of Asian youth, and 9.2% of American Indian/Alaskan Native youth currently have asthma. [2] Its symptoms are associated with increased sedentary behaviors, as well as decreased physical activity and poorer physical fitness and overall health. [1], [3], [4] Regular moderate to vigorous physical activity increases fitness and may improve asthma severity. [5]

The relationship between asthma severity and fitness among youth may vary due to environmental and built environmental factors (e.g., exposure to pollutants or allergens, healthcare access, and housing quality). [6], [7], [8] These neighborhood exposures tend to concentrate in urban areas and contribute to disparities in outcomes observed in urban youth, particularly among youth from minority populations. [9], [10], [11] For example, emergency department visits for 2006-2010 were five times higher for children with asthma living in New York City (NYC) compared to those living in New York State. [9] Prior literature has shown that built environment factors such as increased walkability and greenspace are inversely associated with asthma, and positively associated with physical activity. [12], [13], [14] However, youth living in low-socioeconomic status (SES) neighborhoods often have limited access to quality parks, sidewalks, and exercise facilities, limiting their opportunities for physical activity and fitness promotion. [15] NYC has more than 2300 parks, playgrounds, and recreation facilities across the five boroughs, yet disparities remain in the size, quality, and access to these facilities. Residents in neighborhoods of color have 32% less park space than those in white neighborhoods, and low-income neighborhoods have 19% less park space than those in high-income neighborhoods. [16]

The relationship between asthma status and fitness has been documented, but little is known about how neighborhood factors moderate this relationship. [17] Therefore, this study aimed to examine the longitudinal association of neighborhood-level factors on the relationship between asthma severity and fitness among K-12th-grade NYC youth. We hypothesized that the relationship between asthma severity and fitness would be higher in magnitude for youth residing in low compared with high resource neighborhoods Since built environment and asthma have been independently associated, findings from this study on the intersectional nature of these risks will inform fitness initiatives and future interventions directed towards youth with asthma in low-resource neighborhoods.