Spatio-Temporal Analysis of Asthma Hospitalizations and Associated Factors in Eastern Texas, 2005-2012

Abstract

The prevalence of asthma is increasing for both adult and children in eastern Texas. This study examines the spatial and temporal differences in asthma hospital discharge rates and its association with socioeconomic risk indicators, air pollutants (ozone and NO2) and meteorological variables (temperature, wind speed, and wind direction to an extent). Socioeconomic risk indicators were subjected to principal component analysis to create socioeconomic deprivation index for each county. Annual and diurnal temporal distribution of ozone, NO2, temperature and wind speed were analyzed to understand their characteristics during a wet year (2007) and a dry year (2011). Hotspot analysis and Cluster Outlier analysis of asthma hospitalization examined its association with aforementioned environmental variables at selected metro area in eastern Texas. Socioeconomic indicators were associated with asthma hospital discharge rate both at county and across census tracts in metro areas. Instances when ozone production doesn’t coincide with the NOx and temperature in coastal cities, wind speed and wind direction may play a role. Ozone and NO2 has an inverse relationship with adult and child asthma discharges. Temperature was the only environmental variable with significant association to children asthma discharge rate. Enough evidences exist to suggest high asthma hospital discharges in eastern Texas, but ozone is not a standalone risk factor. Further analysis of weather patterns and air pollutants is required to develop effective asthma action plan.