The Impact Of Air Temperature On Hand,foot And Mouth Disease And Its Prediction Of Future Changes In Shanghai,China

According to the fifth report of IPCC,climate change has spread to all regions of the world.Climate change has had a series of major impacts on ecosystems and people's health,including the epidemic and spread of infectious diseases.Hand,food and mouth disease(HFMD),as a common enterovirus infectious disease,has become one of the high incidence infectious diseases in many countries in recent years.Therefore,in the context of global warming,it has great practical significance to study the impact of future climate change on HFMD health risk under different climate scenarios.Based on the daily temperature data of stations and the number of HFMD visits from January 1,2012 to December 31,2016,the distributed lag nonlinear model(DLNM)was used to study the effect of temperature on HFMD in Shanghai,considering the lag effect of 1-35 days.We also studied the effect of temperature on HFMD health risk when the average temperature in Shanghai increased by 2°C and 4°C threshold,considering the lag effect of 1-14 days and the impact of extreme temperatures.The impact of climate change on the health risk of HFMD is predicted in the future(2031-2050,2051-2070 and 2071-2090)under different climate scenarios(RCP4.5 and RCP8.5)by using data of 9 models provided by CMIP5.The main results are as follows:(1)The annual changes of the average temperature and the number of HFMD patients in Shanghai are unimodal,the high peak appears in summer,and the low peak appears in winter.There was a positive correlation between the average temperature and the number of HFMD cases.The exposure-response curve of HFMD and temperature shows that the optimal temperature range is 16-18°C.(2)The influence of air temperature on the number of patients with HFMD has the lag effect and cumulative effect.The lag effect and cumulative effect of low temperature lasted for about one week,while the lag effect of high temperature lasted for 21 days.The maximum value of relative risk(RR)appeared at-5.5°C(95% CI: 0.896-1.937)of lag 0 day,and the cumulative effect lasted for 35 days.The maximum value appeared at 29.4°C(95% CI: 1.939-2.508)of lag 14 day.With the increase of lag days,the maximum effect moves from high temperature to normal temperature.The lag relative risk of extreme low temperature is slightly greater than that of extreme high temperature,but the duration is within one week.(3)When the average temperature in Shanghai increases by 2°C and 4°C,the impact of temperature is concentrated in the temperature range above 30°C in the first two days and below 10°C in the third to fifth days.The higher the temperature is,the greater the effect is.The effect of low temperature is not obvious.The cumulative effect of extreme high temperature(P99)on the health risk of HFMD is the largest and the longest.When the temperature increases 2°C,the lag and cumulative effects are greater than 4°C,but the effects of extreme temperature are less than 4°C.(4)Under the climate scenarios of RCP4.5 and RCP8.5,the relationship between temperature and HFMD exposure was "U-shaped".With the temperature rising,the impact increased first and then decreased.The average temperature and the number of HFMD cases were more in RCP8.5.In 2031-2090,the greatest impact of temperature on HFMD was concentrated in 23°C-26°C.In 2031-2050,the greatest health risk of HFMD was found,with RCP4.5 of 1.252(95% CI: 1.179-1.330),RCP8.5 of 1.195(95% CI: 1.131-1.262),and 2071-2090 of minimum.In the two scenarios,the lag effect of extreme low temperature is slightly greater than that of extreme high temperature,but there is no positive cumulative effect.However,the health effect is still the largest in 2031-2050,and the smallest in 2071-2090.The lag and cumulative effects of RCP4.5 scenario are greater than those of RCP8.5 scenario.The lag effect of extreme low temperature in RCP4.5 scenario is less than that in RCP8.5 scenario,and the lag effect of extreme high temperature is greater than that in RCP8.5 scenario.(5)Comparing all the results of climate change,we found that in recent years(2012-2016),temperature had the greatest impact on HFMD,with a lag RR of 1.318(95% CI: 0.896-1.937),and a cumulative RR of 2.205(95% CI:1.939-2.508),and so did extreme low temperature,with a RR of 1.067(95% CI:0.963-1.182);the impact of extreme high temperature increased the threshold of 4°C in the average temperature The lag RR was 1.105(95% CI:1.074-1.138),and the cumulative RR was 1.123(95% CI:1.089-1.159).The influence of temperature and extreme low temperature is greater when the average temperature is low,and the influence of extreme high temperature is greater when the average temperature is high.It indicates that climate change has certain impact and a greater health risk on HFMD.