2008—2017年兰州市气象因子与流感发病关系的时间序列研究

Time-series analysis on association between meteorological factors and influenza incidence from 2008 to 2017 in Lanzhou

目的探讨兰州市气象因子与流感发病的关系。方法利用兰州市2008—2017年流感逐日发病数据,结合同期气象资料,采用Spearman相关分析和分布滞后非线性模型(DLNM)分析气象因子对流感发病的影响。结果 2008—2017年兰州市共报告流感4 866例,男女性别比为1.21∶1;以6~14岁儿童发病例数最多,占34.03%;流感发病高峰主要在冬、春季。Spearman相关分析显示,流感日发病例数与气温、相对湿度、降水量呈负相关(rs值分别为-0.232,-0.066,-0.087,P<0.05),与风速呈正相关(r=0.056,P<0.05)。DLNM拟合结果显示,以日均气温11.22℃为参照,气温为33℃、lag 1时RR值最高,为2.70(95%CI:0.41~17.66),但差异无统计学意义(P>0.05);以日均相对湿度50%为参照,相对湿度为0%、lag 0时RR值最高,为7.70(95%CI:1.33~10.42),差异有统计学意义(P<0.05);以日均风速1.25 m/s为参照,风速为0 m/s、lag 14时RR值最高,为3.24(95%CI:0.86~5.24),但差异无统计学意义(P>0.05)。气象因子与流感发病风险关系的总体效应显示,日均气温在-6~0℃和12~20℃时的RR值均>1(P<0.05),日均相对湿度在26%~39%和51%~69%时的RR值均>1(P<0.05),日均风速在0~2 m/s时的RR值均无统计学意义(P>0.05)。结论气象因素是影响兰州市流感发病的重要因素,流感发病风险在低温和低湿环境时相对较高。

Objective To understand the correlation between meteorological factors and influenza in Lanzhou. Methods The historical data on daily incidence of influenza in Lanzhou from 2008 to 2017 and the meteorological data during the same period were collected and the correlation between them were analyzed by Spearman correlation analysis and distributed lag nonlinear model(DLNM). Results From 2008 to 2017,4 866 cases of influenza were reported in Lanzhou. The influenza occurred more often in males,the ratio of males to females was 1.21 ∶1;Influenza also occurred mostly in children aged 6-14(34.03% of all cases);and it also showed peak of prevalence in late winter and early spring. Spearman correlation analysis showed that the number of influenza cases was negatively correlated with temperature(r=-0.232,P<0.05),relative humidity(r=-0.066,P<0.05) and precipitation(r=-0.087,P<0.05),and positively correlated with wind speed(r=0.056,P<0.05). DLNM fitting results showed when the reference of daily average temperature was set to 11.22 ℃,a temperature of 33 ℃ with a lag of 1 day had the highest RR value(2.70,95%CI:0.41-17.66,P>0.05);When the reference daily average relative humidity was set to 50%,a relative humidity of 0% with a lag of 0 day had the highest RR value(7.70,95%CI:1.33-10.42,P<0.05);When the reference daily average wind speed was set to 1.25 m/s,a wind speed of 0 m/s with a lag of 14 days had the highest RR value(3.24,95%CI:0.86-5.24,P>0.05). Average temperature between-6-0 ℃ or 12-20 ℃ had RR values significantly higher than 1(P<0.05). Average relative humidity between 26%-39% or 51%-69% also had RR values significantly higher than 1(P<0.05).RR values revealed no significant differences at wind speed between 0-2 m/s(P>0.05). Conclusion Meteorological factors are important factors affecting the incidence of influenza in Lanzhou,with significantly higher risk under low-temperature and lowhumidity conditions.