Short-term effects and seasonal variation of ozone on daily hospital outpatient visits for childhood asthma in Lanzhou / 北京大学学报(医学版)

ABSTRACT

OBJECTIVE@#To analyze the effects of ozone (O3) concentrations measured with different approaches across different seasons on the total number of childhood asthma-related clinical visits, as well as the differentiation of such effects across different groups of patients.@*METHODS@#The outpatient data of three grade A tertiary hospitals in Lanzhou City spanning from 1 January 2014 to 31 December 2017, as well as air pollution and meteorological data during the same period were collected. Considering the nonlinear relationship between O3 concentrations and the total number of childhood asthma-related clinical visits and meteorological factors, a generalized additive temporal sequence model was employed to analyze the short-term association between changes in O3 concentrations and the total number of childhood asthma-related clinical visits. Taking into account of the variations in O3 concentrations within 1 day, this study adopted different measurement approaches to address the three types of O3 exposures, namely, the maximum 1 h daily concentration (O3max1h), the maximum 8 h daily concentration (O38h) and the mean 24 h daily concentration (O324h) as the short term exposure indicators to O3, followed by a model-based analysis.@*RESULTS@#The increase in short-term exposure levels to O3 in summer had a significant effect on the increase in the total number of childhood asthma-related clinical visits. With lag0 for the current day, every 10 μg/m3 increase in atmospheric concentration of O3max1h was associated with an increase in the total number of childhood asthma-related clinical visits by 3.351% (95%CI 1.231%-5.516%); for every 10 μg/m3 increase in O38h concentration, the total number of childhood asthma-related clinical visits increased by 3.320% (95%CI 0.197%-3.829%); for every 10 μg/m3increase in O324h concentration, the total number of childhood asthma-related clinical visits in summer increased by 6.600% (95%CI 0.914%-12.607%); moreover, an increase in exposure to O3max1h also led to a significant rise in the total number of childhood asthma-related clinical visits among the males.@*CONCLUSION@#The increase in short-term exposure levels to O3 in summer in Lanzhou City has a significant effect on the increase in the total number of childhood asthma-related clinical visits; O3max1h is more closely correlated with the increase in the total number of childhood asthma-related clinical visits.