The effects of meteorological factors on influenza among children in Guangzhou, China

Background Influenza seriously affects the health of children, yet little evidence is available on the association between meteorological factors and the occurrence of influenza among children in subtropical regions. The current study aimed to explore the effects of meteorological factors on influenza among children in Guangzhou, a subtropical city in China. Methods The distributed lag nonlinear model (DLNM) was used to assess the effects of meteorological factors on children influenza occurrence in Guangzhou, China. Daily number of influenza cases among children aged 0-17 years from 2013 to 2017 were obtained from the National Information System for Disease Control and Prevention. Results Mean temperature, relative humidity, and atmospheric pressure were associated with influenza cases. The relative risks (RRs) increased as temperature fell below 20 degrees C. The relationship between relative humidity and influenza cases could be described with a U-shaped curve, and the RRs increased if relative humidity was lower than 50% or higher than 80%. The risk of influenza increased with rising atmospheric pressure with 1005 hPa as the break point. The cold effect, humid effect, dry effect, high-pressure effect, and low-pressure effect showed statistical significance both in female and male. The cold effect increased with age. The humid-effect affects all age ranges of children, but dry effect mainly affected 4-14 years old. High-pressure effect mainly affected the 0-3 years old, whereas low-pressure effect protected preschool children aged 0-6 years old. Conclusion Mean temperature, relative humidity, and atmospheric pressure might be important predictors of the influenza occurrence among children in Guangzhou.