Effect of ambient temperature on incidence of tuberculosis and effect modification by meteorological factors in Jinan, China during 2012-2015

Abstract ObjectiveFor assessing the nonlinearity and delayed effect of temperature on incidence of Tuberculosis (TB) and effect modification by meteorology factors, daily data on meteorological factors, air pollutants and incidence were obtained in Jinan, China, from 2012 to 2015.MethodsA distributed lag non-linear model (DLNM) combined with quasi-Poisson regression model was employed to assess the nonlinearity and the delayed effect of associations. We further built a series of weather-stratified models categorizing the meteorology factors into two levels to assess the effect modification of the ambient temperature effect. ResultsThe correlation between tuberculosis (TB) cases and daily average temperature (Tmean) was nonlinear with a delayed effect. At the current day (lag 0), the increase of Tmean decreased the risk of TB incidence; over lag 0-70 days, the decrease of low Tmean and the increase of the high Tmean both indicated the increased risk of TB. The cold temperature showed an immediate effect at the current day, with a harvesting effect in the following days. There was no significant harvesting effect in hot effect. Meanwhile, the effect of hot temperature on TB appeared with an about two-week lag and was lower than cold effect. The effect modifications by relative humidity, wind speed and sunshine duration were observed.ConclusionResults indicate that there was a nonlinear correlation with a harvesting effect between temperature and TB in Jinan, and both cold effect and heat effect exist the delayed effect. Results also pointed to the importance of considering effect modification by meteorological factors in assessing temperature effects on incidence of TB. Which might shed light on the strategy of TB prevention and control.