Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong Province 511430, China; Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
Sci Total Environ. 2019 Nov 15;691:549-561. doi: 10.1016/j.scitotenv.2019.06.382. Epub 2019 Jul 4.
Mounting evidence suggests that short-term exposure to ozone increases the risk of asthma exacerbations. However, ozone exposures have been assessed using ambient ozone concentrations averaged over different time periods in different studies.
To evaluate the risks for asthma exacerbations related to ambient ozone measured as 1-hour or 8-hour daily maximum and 24-hour average concentrations.
Based on a literature search in PubMed, EMBASE and Web of Science, we identified all time-series studies as of December 4th, 2018 and included 47 eligible studies in our analyses. Asthma exacerbation is defined as the risk for emergency room visits or hospital admissions. Pooled relative risks (RRs) and 95% confidence intervals (95%CIs) for a 10 μg/m3 increase in daily ozone concentration were estimated using random effect models. Subgroup analyses and sensitivity analyses were also performed to examine the risks for different seasons, regions and age groups and for the robustness of our main findings.
Significant and similar associations were found for O3-1 h max (RR,1.012; 95%CI, 1.005-1.019) and O3-8 h max (RR, 1.011; 95%CI, 1.007-1.014), while marginal effect was identified for O3-24 h average (RR, 1.005; 95%CI, 0.996-1.014). No significant publication bias but high heterogeneities were observed. During the warm season, ozone was significantly associated with asthma exacerbation. O3-1 h max had the highest RR of 1.014 (95%CI, 1.005-1.024), followed by O3-8 h max (RR, 1.012; 95%CI, 1.009-1.016), while marginal association was identified for O3-24 h avg (RR, 1.008; 95%CI, 0.998-1.017). During the cold season, null associations were identified for all the three averaging times. Variations were also observed in region and age.
Ozone exposure measured as 1-hour or 8-hour daily max were more consistently associated with asthma exacerbations than 24-hour average exposure during the warm season.
越来越多的证据表明，短期接触臭氧会增加哮喘恶化的风险。然而，在不同的研究中，臭氧暴露的评估是使用不同时间段的环境臭氧浓度平均值进行的。
评估以 1 小时或 8 小时日最大和 24 小时平均浓度表示的环境臭氧与哮喘恶化相关的风险。
基于对 PubMed、EMBASE 和 Web of Science 的文献检索，我们确定了截至 2018 年 12 月 4 日的所有时间序列研究，并将 47 项符合条件的研究纳入我们的分析。哮喘恶化定义为急诊就诊或住院的风险。使用随机效应模型估计每日臭氧浓度增加 10μg/m3 时的汇总相对风险（RR）和 95%置信区间（95%CI）。还进行了亚组分析和敏感性分析，以检查不同季节、地区和年龄组的风险，以及对我们主要发现的稳健性。
发现 O3-1h max（RR，1.012；95%CI，1.005-1.019）和 O3-8h max（RR，1.011；95%CI，1.007-1.014）存在显著且相似的关联，而 O3-24h avg 则存在边缘效应（RR，1.005；95%CI，0.996-1.014）。虽然观察到没有显著的发表偏倚，但存在高度异质性。在温暖季节，臭氧与哮喘恶化显著相关。臭氧 1 小时最大值的 RR 最高，为 1.014（95%CI，1.005-1.024），其次是臭氧 8 小时最大值（RR，1.012；95%CI，1.009-1.016），而臭氧 24 小时平均值的关联则较为边缘（RR，1.008；95%CI，0.998-1.017）。在寒冷季节，所有三种平均时间都没有发现关联。在不同地区和年龄组也观察到了差异。
在温暖季节，与 24 小时平均暴露相比，以 1 小时或 8 小时日最大臭氧浓度表示的臭氧暴露与哮喘恶化更密切相关。
