Epidemiological studies of acute ozone exposures and mortality
Epidemiological studies of acute ozone exposures and mortality
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DOI：
10.1038/sj.jea.7500169
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发表时间：
2001-07-01
期刊：
影响因子：
--
通讯作者：
Ito, K
中科院分区：
文献类型：
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作者：
Thurston, GD;Ito, K
关于臭氧（O-3）空气污染的许多（但不是全部）观察性流行病学研究已经得出结论，这种污染物的日常环境浓度变化与一系列广泛的不利健康后果之间存在显著关联。我们评估了一些过去的流行病学研究，这些研究评估了O-3与死亡率的短期关联，并调查了它们对O-3效应估计差异的一个可能原因，即它们对天气对死亡率影响的建模方法的差异。对于考虑的所有总死亡率-空气污染时间序列研究，综合分析得出了相对风险，每日1小时最大O-3每增加100 ppb， RR=1.036 （95% Cl: 1.023-1.050）。然而，特定温度-死亡率关联的非线性性质的研究子集得出的综合估计RR=1.056 / 100 ppb （95% CI: 1.032-1.081）。这表明，过去使用线性温度-死亡率规范的时间序列研究低估了O-3空气污染对过早死亡的影响。对于密歇根州底特律市，1985-1990年期间每日总死亡率的说明性分析也表明，模式天气规格的选择可以影响O-3健康影响的估计。对不同天气规格的结果进行了相互比较。温度和相对湿度（RH）非线性指标的相关系数较低；与采用简单的冷热样条的基本模型相比，该模型具有更大的O-3系数和更大的O-3 RR估定值。我们得出的结论是，与颗粒物（PM）质量不同，通过时间序列分析得出的O-3死亡率影响估计可能对模型中处理天气的方式很敏感。对于其他主要依赖于温度形成机制的污染物，如二次气溶胶，情况可能也是如此。一般来说，我们发现，当将温度-健康效应关联的非线性和湿度相互作用纳入模式天气规范时，o -3死亡率效应估计的大小和统计显著性都会增加。我们建议在指定这样的模型时，考虑最小化模型系数的相互关系（以及其他关键因素，如拟合优度、自相关和过度分散），特别是当要为风险估计解释单个系数时。
Many, but not all, observational epidemiological studies of ozone (O-3) air pollution have yielded significant associations between variations in daily ambient concentrations of this pollutant and a wide range of adverse health outcomes. We evaluate some past epidemiological studies that have assessed the short-term association Of O-3 with mortality, and investigate one possible reason for variations in their O-3 effect estimate, i.e., differences in their approaches to the modeling of weather influences on mortality. For all of the total mortality-air pollution time-series studies considered, the combined analysis yielded a relative risk, RR=1.036 per 100-ppb increase in daily 1-h maximum O-3 (95% Cl: 1.023-1.050). However, the subset of studies that specified the nonlinear nature of the temperature-mortality association yielded a combined estimate of RR=1.056 per 100 ppb (95% CI: 1.032-1.081). This indicates that past time-series studies using linear temperature-mortality specifications have underpredicted the premature mortality effects of O-3 air pollution. For Detroit, Ml, an illustrative analysis of daily total mortality during 1985-1990 also indicated that the model weather specification choice can influence the O-3 health effects estimate. Results were intercompared for alternative weather specifications. Nonlinear specifications of temperature and relative humidity ( RH) yielded lower intercorrelations; with the O-3 coefficient, and larger O-3 RR estimates, than a base model employing a simple linear spline of hot and cold temperature. We conclude that, unlike for particulate matter (PM) mass, the mortality effect estimates derived by time-series analyses for O-3 can be sensitive to the way that weather is addressed in the model. The same may well also be true for other pollutants with largely temperature-dependent formation mechanisms, such as secondary aerosols. Generally, we find that the O-3-mortality effect estimate increases in size and statistical significance when the nonlinearity and the humidity interaction of the temperature-health effect association are incorporated into the model weather specification. We recommend that a minimization of the intercorrelations of model coefficients be considered (along with other critical factors such as goodness of fit, autocorrelation, and overdispersion) when specifying such a model, especially when individual coefficients are to be interpreted for risk estimation.