Effect of temperature on the risk of varicella in Lu'an City / 预防医学

ABSTRACT

Objective@#To examine the effect of temperature on the risk of varicella in Lu'an City, Anhui Province, so as to provide insights into varicella prevention and control. @*Methods@#Data on incidence of varicella in Lu'an City from 2010 to 2021 were collected from Chinese Disease Prevention and Control System, and meteorological data in Lu'an City were also collected from National Meteorological Science Data Center and China National Urban Air Quality Real-Time Publishing Platform during the same period. The effect of temperature on the risk of varicella was examined using a distributed lag non-linear model (DLNM) and subgroup analyses for gender and age were conducted. The effects of extremely low and high temperatures on the cumulative risk of varicella and trends in the cumulative risk of varicella over time were analyzed using a time-varying DLNM. @*Results@# Totally 25 318 varicella cases were reported in Lu'an City from 2010 to 2021, including 15 013 men (59.30%) and 10 305 women (40.70%). The median number of varicella cases was 4 (interquartile range, 6) cases, and the daily median air temperature was 17.50 (interquartile range, 15.80) ℃, with the lowest temperature recorded as -5.80 ℃ and the highest temperatures as 34.90 ℃. The results from the DLNM showed that the extremely low temperatures reduced the risk of varicella (RR=0.522, 95%CI 0.375-0.728) in relative to median temperature, while extremely high temperature increased the risk of varicella (RR=1.604, 95%CI 1.112-2.316). Subgroup analysis revealed the effect curve for men was similar to total populations (extremely low temperature RR=0.497, 95%CI 0.331-0.746; extremely high temperature RR=1.978, 95%CI 1.260-3.106), and the effect of temperature on varicella risk was mainly concentrated among children at ages of 6 to 12 years (extremely low temperature RR=0.426, 95%CI 0.247-0.736; extremely high temperature RR=2.431, 95%CI 1.378-4.288). The results from the time-varying DLNM revealed that the cumulative risk of varicella due to both extremely low and high temperatures appeared a tendency towards a rise over years (P<0.05). @*Conclusions@#Low temperature may reduce the risk of varicella, while high temperature increases the risk of varicella in Lu'an City, which is more remarkable among men and children at ages of 6 to 12 years. The cumulative risk of varicella at both extremely low and high temperatures shows a tendency towards a rise over years.