大气SO2暴露与医院每日急诊和门诊人次关系的多中心时间序列研究

  目的  分析大气二氧化硫(sulfur dioxide, SO₂)暴露对北京、西安、武汉和广州市等地医院每日急诊和门诊人次的影响。  方法  收集2013年1月1日至2015年12月31日上述城市5家医院的急诊和门诊资料、大气污染物资料和气象资料。采用广义相加模型分析SO₂浓度与医院每日急诊和门诊人次的关系，采用Meta随机效应模型分析得到合并效应值。  结果  纳入总急诊和门诊人次分别为411 277和4 935 282人次。北京、西安、武汉和广州市等地的SO₂年平均浓度分别为16.5、30.1、30.5和15.0 μg/m3。SO₂对急诊和门诊的影响存在滞后效应，单日滞后效应逐日递减，且在滞后3 d失去统计学意义。滞后0~2 d影响最大，SO₂平均浓度每升高10 μg/m3，每日急诊和门诊分别增加3.44%(95% CI:1.65%~5.26%)和1.32%(95% CI:0.45%~2.20%)。SO₂对每日急诊和门诊影响的暴露-反应关系曲线均呈近似线性，但在高浓度段有变平缓的趋势。此外，SO₂引起的急诊和门诊人群归因分值分别为6.80%(95% CI:2.20%~11.10%)和2.84%(95% CI:0.98%~4.64%)。  结论  中国城市SO₂短期暴露可增加医院急诊和门诊的就诊风险，应加强SO₂污染防治并修订相应标准。

Association between sulfur dioxide air pollution and daily hospital emergency and outpatient visits: a multi-city time-series study

  Objective  To assess the effects of sulfur dioxide (SO₂) air pollution on daily hospital emergency and outpatient visits in Beijing, Xian, Wuhan, and Guangzhou.  Methods  The daily data on emergency and outpatient visits, ambient air pollutants, and weather conditions of 5 hospitals in Beijing, Xian, Wuhan, and Guangzhou were collected from January 1, 2013 to December 31, 2015. Generalized additive models were applied to analyze the effects of SO₂ exposure on daily hospital emergency and outpatient visits. Random-effects meta-analyses were used to obtain the combined effect values.  Results  The included emergency and outpatient visits of 5 hospitals were 411 277 and 4 935 282, respectively. The average annual SO₂ levels of Beijing, Xian, Wuhan, and Guangzhou were 16.5, 30.1, 30.5, and 15.0 μg/m3, respectively. The lag effects of SO₂ exposure on emergency and outpatient visits were observed in our study. For the single-day lag periods, the estimated effect of the same-day exposure was the largest. Afterward, the effect decreased and lost statistical significance in the lag 3 d. Our results showed that the lag 0-2 d concentrations of SO₂ had the largest effect on emergency and outpatient visits. And a 10 μg/m3 increment in SO₂ concentrations was associated with excess risks of 3.44% (95% CI: 1.65%-5.26%) and 1.32% (95% CI: 0.45%-2.20%) for daily emergency and outpatient visits, respectively. The exposure-response curves between SO₂ exposure and daily emergency and outpatient visits were nearly linear, but the curves turned to level off at higher concentrations. Besides, SO₂-related population attributable fractions were 3.33% (95% CI: 1.63%-4.99%) and 1.31% (95% CI: 0.45%-2.16%) for daily emergency and outpatient visits, respectively.  Conclusions  Short-term exposure to SO₂ can increase the risk of hospital emergency and outpatient visits in Chinese cities, suggesting that the prevention and control of SO₂ pollution should be further strengthened, and the corresponding air pollution standard should be tightened.