Lag effect of daily average temperature on the occurrence of urticaria in Lanzhou city / 中华皮肤科杂志

ABSTRACT

Objective To evaluate effects of daily average temperature on the occurrence of urticaria in Lanzhou city,and to analyze differences in the effects between different populations.Methods Time-series data on daily outpatient visits for urticaria between January 1,2007 and December 31,2013 were collected from the First Hospital of Lanzhou University and Lanzhou University Second Hospital.Daily meteorological data during this peroid were obtained from the Gansu Meteorological Bureau.Distributed lag non-linear models were used to analyze the association between daily average temperature and occurrence of urticaria,and the analysis was stratified by age and gender.Results The association between daily average temperature and daily number of outpatient visits for urticaria was nonlinear.Low temperature had significant lag effects on the daily number of outpatient visits for urticaria,with the maximum relative risk (RR) value (1.014 [95％ CI 1.000-1.023]) observed at 6 ℃ on lag day 18.Stratification analysis demonstrated that the effects of high temperature on the number of outpatient visits for urticaria were apparent on the day of exposure in age groups of 0-18 and 19-64 years,but decreased on the day of exposure in the age group ≥ 65 years.The effects of low temperature,which showed similar trends along with the increment of lag days in all groups,were relatively delayed and occurred 2 to 4 days after exposure.Conclusions Air temperature affects the occurrence of urticaria in Lanzhou city.Low temperature has evident lag effects on the occurrence of urticaria,while high temperature does not have.