广州市气象因素与流感样病例关系的时间序列研究

Effect of Meteorological Factors on Risk of Influenza-Like Illness in Guangzhou: A Time-Series Analysis

目的明确广州市气温和湿度短期变异对流感样病例(influenza-like illness,ILI)发病风险的影响。方法从广东省疾病预防控制中心流感监测系统收集广州市2010—2015年期间每周所有哨点监测医院的ILI监测数据,从广州市气象局获得同期每周的气象资料(包括平均气温(TM)和相对湿度(RH)),并根据这些指标计算出水汽压指标(mb),用于代表绝对湿度。使用分布滞后非线性模型(Distributed Lag Nonlinear Model,DLNM)来评估气温和湿度的短期变化(Lag 2周)对ILI的影响。结果广州市ILI的发病高峰期主要在冬春季和夏季。ILI与平均气温存在非线性的关系。随着气温的上升,ILI风险呈先上升后降低的趋势,当平均气温为14℃时,ILI风险最高。与25℃相比,平均气温为14℃时ILI的风险增加0.053 8%(95%CI:0.035 1%～0.072 6%)。随着绝对湿度的增加,ILI风险亦呈先上升后下降的趋势。与22 mb相比,绝对湿度为10 mb时ILI的风险最高,增加0.049 1%(95%CI:0.031 8%～0.066 4%)。然而,相对湿度与ILI的相关性相对较弱。联合作用分析发现,低温低湿条件下ILI风险较高。结论气温和绝对湿度均与ILI的风险存在相关性,ILI的风险在低温和低湿环境时较高。

Objectives The aim of this study was to investigate the impact of short-term variation of temperature and humidity on the risk of influenza-like illness（ILI）. Methods ILI monitoring data for each week from all sentinel monitoring hospitals in Guangzhou in 2010-2015 were collected from the influenza surveillance system of Guangdong Provincial Center for Disease Control and Prevention. Meteorological data of each week, including mean temperature（TM） and relative humidity（RH）, in Guangzhou during the same period were obtained from Guangzhou Meteorological Bureau. Then vapor pressure（VP） was calculated with these indicators representing the absolute humidity（AH）. A distributed lag non-linear model（DLNM） was used to assess the short-term（Lag 2 weeks） effect of temperature and humidity on the risk of ILI. Results The peak season for ILI was mainly in winter, spring and summer. There was a nonlinear relationship between ILI and mean temperature. As temperature rising, the risk of ILI increased at first and then decreased. When the mean temperature was 14℃, the relative risk of ILI was the highest. Compared with the mean temperature at 25℃, the risk of ILI in 14℃ increased 0.053 8%（95%CI：0.035 1%～0.072 6%）. As the absolute humidity rising, the risk of ILI was also increased at first and then decreased. Compared with the absolute humidity at 22 mb, the risk of ILI increased 0.049 1%（95%CI： 0.031 8%～0.066 4%） at 10 mb. Conversely, the association between relative humidity and ILI was relatively weak. An analysis on the combined effect found that the risk of ILI was higher in low temperature and low humidity. Conclusions Temperature and absolute humidity were associated with the risk of ILI, and the risk of ILI was higher in low temperature and low humidity.