Impact of Temperature on Upper Respiratory Tract Infections in Lanzhou Based on the Distributed Lag Model

The study mainly analyzed the relationship between temperature and the upper respiratory tract infections (URI) in Lanzhou. We collected the daily URI and meteorological data from 2010 to 2015. A distributed lag non-linear model was used to examine the relationship and potential effects of different temperatures and different lag days on the morbidity of URI. The results showed that the morbidity of URI was significantly related to the meteorological factors, and the peak of the onset of the disease usually occurred between November and February the next year. The correlation analysis was carried out between meteorological factors and URI cases, and the result revealed that the daily morbidity of URI in Lanzhou was related to air temperature, air pressure, and wind speed. The exposure effect curve of average daily temperature to different sex and different age groups in Lanzhou displayed an M-shaped. Temperature had a certain lag effect on the daily morbidity of URI. For low temperature, it appeared on the present day, and the maximum impact appeared at lag 2 days and persisted for 12 days. The female was more vulnerable than the male, and the impact was obvious in teenagers and the elderly and not obvious in adult. Meteorological factors play an important role in the occurrence of URI in Lanzhou, but the main factor is low temperature. Temperature can trigger the morbidity of URI directly; it can induce various symptoms of URI (such as cold, sore throat and rhinitis) and directly affect the distribution of URI in the population.