Am J Epidemiol. 2023 Jun 2;192(6):949-962. doi: 10.1093/aje/kwad032.
Heat and tropospheric ozone have acute impacts on rates of premature death. Warm temperatures affect the photochemical processes in ozone formation, suggesting ozone as a mediator of the acute health effect of heat on mortality. We assembled a summertime daily time-series data set of 15 French urban areas during 2000-2015 to decompose the acute total effect of heat waves on mortality into natural direct and indirect effects using a regression-based product method under the potential outcomes framework. For each area, we estimated the effect of heat waves on mortality using a quasi-Poisson model with adjustment for covariates such as lagged nitrogen dioxide concentration, and we modeled ozone with a linear regression of heat waves and the same set of covariates. We pooled estimates across areas using random-effects models. We also provide R software code (R Foundation for Statistical Computing, Vienna, Austria) with which to reproduce or replicate our analysis. Most areas demonstrated evidence of mediation by ozone, with the pooled relative risks for natural indirect effects being 1.03 (95% confidence interval (CI): 1.02, 1.05), 1.03 (95% CI: 1.01, 1.04), and 1.04 (95% CI: 1.00, 1.07) for nonaccidental, cardiovascular, and respiratory mortality, respectively. We found evidence of a mediation effect by ozone in the association between heat waves and mortality in France which varied by geographic location and cause of mortality.
热和对流层臭氧对过早死亡的发生率有急性影响。高温会影响臭氧形成的光化学反应过程，这表明臭氧是热对死亡率的急性健康影响的中介。我们组装了 2000 年至 2015 年期间法国 15 个城市夏季的每日时间序列数据集，以潜在结果框架下的回归乘积法将热浪对死亡率的急性总影响分解为自然直接和间接影响。对于每个地区，我们使用拟泊松模型调整滞后氮氧化物浓度等协变量来估计热浪对死亡率的影响，并使用线性回归模型来模拟臭氧与热浪和相同协变量集。我们使用随机效应模型对各地区的估计值进行汇总。我们还提供了 R 软件代码（R 基金会，维也纳，奥地利），可用于重现或复制我们的分析。大多数地区都证明了臭氧的中介作用，自然间接效应的 pooled relative risks 分别为 1.03（95%置信区间（CI）：1.02，1.05）、1.03（95% CI：1.01，1.04）和 1.04（95% CI：1.00，1.07），分别用于非意外、心血管和呼吸性死亡率。我们发现，在法国，热浪与死亡率之间的关联存在臭氧的中介效应，其因地理位置和死亡率原因而异。
