Does the presence of vegetation affect asthma hospitalizations

The relationship between elderly asthma hospitalizations and the differential presence of vegetation was investigated through the analysis of normalized differential vegetation index (NDVI) as a proxy for vegetation vigor, and Medicare hospitalization records in seven states from 2005-2006. It was hypothesized that mature vegetation would reduce asthma hospitalizations, and seasonal NDVI increases and proximity to traffic-related air pollution would increase the hospitalization rate (HR).;Time-series analysis identified seasonal patterns in elderly asthma hospitalizations. This pattern is characterized as counter-phase with NDVI; when vegetation vigor is higher the HR decreases. Influenza seasonality was found to significantly affect the HR. Spatial zip code-based analysis identified that residential proximity to highways, income, and percent of impervious land cover were significant predictor variables. Asthma hospitalizations increased significantly (p<0.001) for both very rural and very urban zip codes of residence.