California Office of Environmental Health Hazard Assessment, Air Pollution Epidemiology Section, 1515 Clay Street, 16th floor, Oakland, CA 94612, USA.
Environ Res. 2011 Nov;111(8):1286-92. doi: 10.1016/j.envres.2011.09.006. Epub 2011 Oct 5.
Investigators have consistently demonstrated associations between elevated temperatures and mortality worldwide. Few have recently focused on identifying vulnerable subgroups, and far fewer have determined whether at least some of the observed effect may be a manifestation of mortality displacement. We examined mean daily apparent temperature and mortality in 13 counties in California during the warm season from 1999 to 2006 to identify age and disease subgroups that are at increased risk, and to evaluate the potential effect of mortality displacement. The time-series method using the Poisson regression was applied for data analysis for single lag days of 0-20 days, and for cumulative average lag days of five and ten days. Significant associations were observed for the same-day (excess risk=4.3% per 5.6 °C increase in apparent temperature, 95% confidence interval: 3.4, 5.2) continuing up to a maximum of three days following apparent temperature exposure for non-accidental mortality. Similar risks were found for mortality from cardiovascular diseases, respiratory diseases, and among children zero to 18 years of age, and adults and the elderly 50 years and older. Since no significant negative effects were observed in the following single or cumulative days, evidence of mortality displacement was not found. Thus, the effect of temperature on mortality appears to be an event that occurs within three days following exposure, and requires immediate attention for prevention.
研究人员一致证明，全球范围内气温升高与死亡率之间存在关联。最近很少有人关注确定易受影响的亚组，更少有人确定观察到的影响是否至少部分是死亡率转移的表现。我们研究了 1999 年至 2006 年暖季加利福尼亚州 13 个县的平均每日明显温度和死亡率，以确定处于高风险的年龄和疾病亚组，并评估死亡率转移的潜在影响。使用泊松回归的时间序列方法应用于单滞后天数为 0-20 天的数据分析，以及累积平均滞后天数为 5 天和 10 天。在暴露于明显温度后的相同天数（超额风险=每 5.6°C 增加 4.3%，95%置信区间：3.4，5.2），非意外死亡率观察到明显关联。在心血管疾病、呼吸道疾病以及 0 至 18 岁儿童和 50 岁及以上成年人和老年人中也发现了类似的风险。由于在随后的单天或累积天数中未观察到明显的负效应，因此未发现死亡率转移的证据。因此，温度对死亡率的影响似乎是暴露后三天内发生的事件，需要立即注意预防。
