北京市PM2.5浓度与荨麻疹门诊人次的关系研究

目的：探讨北京市环境空气污染物浓度与每日荨麻疹门诊量的关系。方法主要采用时间序列结合分布滞后非线性模型和Spearman相关性分析来研究PM2.5与荨麻疹门诊量的关系，以每升高一个四分位间距（82.8μg/m3）引起的荨麻疹就诊量增加的RR值表示PM2.5对荨麻疹的效应。结果研究期间，PM2.5、温度、湿度及荨麻疹日门诊量分别为89.3μg/m3、12.7℃、51.9%、27.3人次。PM2.5与日均温度，相对湿度及荨麻疹门诊人次的Spearman相关系数分别是-0.21、0.49、0.01，前两者差异有统计学意义，荨麻疹门诊人次与日均温度，相对湿度的Spearman相关系数分别是0.36、0.31，差异有统计学意义。在lag0?14时，RR值为1（95%CI：0.89，1.13），而控制混杂因素后， PM2.5对荨麻疹每日门诊量滞后20 d的累积效应RR值为1.22（95%CI：1.03?1.46）（P<0.05），滞后效应明显延长。结论 PM2.5与荨麻疹门诊量的关系易受气象因素、生物性混杂因素的影响，其中相对湿度、平均温度均与荨麻疹就诊量呈正相关。

Association between PM2.5 concentrations and the daily number of outpatient visits for urticaria in Beijing city

Objective To investigate the association between concentrations of environmental air pollutants and the daily number of outpatient visits for urticaria in Beijing. Methods Time series analysis in combination with distributed lag non?linear model(DLNM)and Spearman′s rank correlation test was used to analyze the association between PM2.5 concentrations and the daily number of outpatient visits for urticaria. All effect estimates were expressed as a risk ratio(RR)for the daily number of outpatient visits with an interquartile range(IQR)increase of 82.8 μg/m3 in PM2.5. Results From January 1st 2013 to June 30th 2014, the daily average PM2.5 concentration, temperature, relative humidity and number of visits for urticaria were 89.3 μg/m3, 12.7 ℃, 51.9% and 27.3 respectively. Spearman′s rank correlation test showed that the daily average PM2.5 concentration and number of visits for urticaria were correlated with daily mean temperature(rs =-0.21, 0.36, respectively, P < 0.05)and relative humidity(rs = 0.49, 0.31, respectively, P < 0.05), but no correlation was observed between daily average PM2.5 concentrations and daily number of visits for urticaria(rs=0.01, P>0.05). There was no significant correlation between daily number of outpatient visits for urticaria and daily PM2.5 concentration lagged by 0-14 days(RR=1, 95%CI:0.89, 1.13). After potential confounding factors were adjusted, an 82.8μg/m3 increase in daily PM2.5 concentration at lag 0-20 days was significantly associated with a 22%(95%CI:3%, 46%)increase in daily number of outpatient visits for urticaria, suggesting that the lagged effect of PM2.5 was obviously increased. Conclusion The association between PM2.5 concentrations and the number of visits for urticaria is easily affected by meteorological factors and biological confounding factors, and relative humidity and mean temperature are both positively correlated with the number of visits for urticaria.