AUTHOR=Yin Jia , Liu Ti , Tang Fang , Chen Dongzhen , Sun Lin , Song Shaoxia , Zhang Shengyang , Wu Julong , Li Zhong , Xing Weijia , Wang Xianjun , Ding Guoyong 

TITLE=Effects of ambient temperature on influenza-like illness: A multicity analysis in Shandong Province, China, 2014–2017

JOURNAL=Frontiers in Public Health

VOLUME=Volume 10 - 2022

YEAR=2023

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2022.1095436

DOI=10.3389/fpubh.2022.1095436

ISSN=2296-2565

ABSTRACT=Background: The associations between ambient temperature and influenza-like illness (ILI) have been investigated in previous studies. However, they have inconsistent results. The purpose of this study was to estimate the effect of ambient temperature on ILI in Shandong Province, China.
Methods: Weekly ILI surveillance and meteorological data over 2014–2017 in Shandong Province were collected from Shandong Center for Disease Control and Prevention and China Meteorological Data Service Center, respectively. A distributed lag non-linear model was adopted to estimate city-specific temperature-ILI relationships, which were used to pool the regional-level and provincial-level estimates through multivariate meta-analysis.
Results: There were 911,743 ILI cases reported in the study area between 2014 and 2017. The risk of ILI increased with decreasing weekly ambient temperature at the provincial level, and the effect was statistically significant when the temperatures was less than –1.5°C (RR=1.24, 95% CI: 1.00–1.54). We found that the relationships between temperature and ILI showed L-shaped at regional level, expect for Southern of Shandong (S-shaped). The risk of ILI was influenced by the cold effect, with significant lags from 2.5 to 3 weeks, and no significant hot effect on ILI were found.
Conclusions: Our findings confirm that low temperatures have significantly increase the risk of ILI in the study area. In addition, the cold effect of ambient temperature may cause more risk of ILI than the hot effect. The findings have significant implications for developing strategies to control ILI and respond to climate change.