2013年初灰霾期间太原市空气污染与医院门诊量的相关性分析

The association of air pollution with outpatient visits in a hospital of Taiyuan at early 2013

目的探讨并描述2013年1月灰霾期间太原市空气污染与医院门诊量的关系。方法门急诊量数据来自太原市某综合医院,空气污染指数(API)来源于山西省环保厅网站,气温数据来源于天气网。研究时间为2012年10月—2013年1月(灰霾期,T1序列)和2011年10月—2012年1月(对照期,T2序列)。控制门诊量的自然增长后,通过两个序列数据的比较计算日门诊百分增量。用广义相加模型确定浓度-反应关系并描述其特征;利用多种结构断裂点测试确定曲线的拐点;以约束分段线性模型估计不同线段斜率,估算相应的危险度。结果两个时间序列门诊量没有明显的差异;API与医院门诊量存在相关关系,儿科、呼吸内科与空气污染浓度-反应曲线呈"C"型,API每升高10个单位,门诊量分别增加13.4%(avg02)和9.8%(lag5)。耳鼻喉科、妇产科和皮肤科的曲线则呈"J"型,API每升高10个单位,门诊量分别增加29.2%(avg07)、23.4%(avg07)和17.2%(avg07)。结论 2013年1月灰霾期间,本次调查的太原市医院门诊量没有明显的改变;空气污染与医院多科室的门诊量存在相关关系。

Objective To explore and descript the association of air pollution with outpatient visits in a hospital of Taiyuan during 2013 haze episode. Methods Data of outpatient visits were collected in a comprehensive hospital in Taiyuan. Data of API was gained from Shanxi Environmental Protection Bureau website, and data of weather from China Weather website. The observation period was from Oct.2012 to Jan.2013（T1series）, and Oct.2011 to Jan.2012（T2series）. The increment of hospital outpatient visits was calculated through comparing daily visits of two series. Generalized additive model（GAM） was used to identify the exposure-response relation（ERR）, then multiple structural change test was employed to determine the change points in ERRs and constrained piecewise linear function was used to estimate risks for different segments of ERR. Results There were no significant changes observed for the number of hospital outpatient visits in T1 series compared with T2 series. There was non-liner concentration-response relationship between API and outpatient visits. The concentration-response relation curve between API and outpatient visits to pediatric and respiratory showed C-shape. The number of outpatient visits will increase 13.4% and 9.8%, respectively, with increase of 10 units of API. The curve for ear-nose-throat, gynaecological and dermatological showed the J-shape, and the number of outpatient will increase 29.2%（avg07）, 23.4%（avg07） and 17.2%（avg07）, respectively,with increase 10 units of of API. Conclusion No significant change is observed for hospital outpatient visits during Jan.2013 in Taiyuan. Air pollution is associated with outpatient visits.