Spatiotemporal variations of asthma admission rates and its relationship with environmental factors in Guangxi, China

BackgroundThe association between environmental factors and asthma has attracted much attention. Numerous studies have focused on the effects of air pollution or meteorological factors, but the synergistic effects and regional heterogeneity remain unclear. MethodsBetween 2014 and 2015, 8,563 hospital admissions in 2014 and 7,804 hospital admissions in 2015 due to asthma were collected from 14 regions in Guangxi, China. First, we performed a Spearman correlation coefficient model as the single factor analysis to estimate correlation between environmental factors and asthma hospitalization rates in multiple regions. Second, Generalized Additive Model (GAM) was used to analyze the synergistic effects of environmental factors on asthma hospitalization rates in 14 regions, respectively.ResultsThe results indicated that asthma hospitalization rates were high in spring and autumn. There were all nonlinear relationships between air pollutants, meteorological factors and asthma hospitalization rates, and the relationships were different from region to region. According to the single factor analysis, asthma hospitalizations were related to the daily temperature, daily range of temperature, CO, NO2, and PM2.5 in multiple regions. According to the result of synergistic effects analysis, the adjusted R-square was high in Beihai and Nanning, with values of 0.292 and 0.207, which meant that environmental factors were powerful in explaining changes of asthma hospitalization rates in Beihai and Nanning.ConclusionDaily range of temperature is an important factor impact on asthma, which should be considered in the analysis of environmental factors impact on asthma. It is suggested that the relationship between asthma and risk factors in different regions deserves additional study. Governments should develop targeted protective measures for asthma in different regions.