The Effect Of Meteorological Factors On Hand-Foot-Mouth Disease Among Children Aged 0~14 Years:A Study In Jiayuguan City,China

Research backgroundThe hand-foot-mouth disease?HFMD?is a common infectious disease caused by kinds of viruses such as enterovirus 71?EV71?,coxsackie virus?Cox?group A,group B,and so on,which mainly infects infants and little kids aged 0-5 years old.In 2008,there was an outbreak of HFMD in some areas of Anhui Province,China,and later the epidemic spread to 28 provinces in China within the next 3 months.A total of 488,955cases of HFMD were reported.In the same year,in order to strengthen the monitoring and control of the HFMD epidemic,the National Health Commission of the People's Republic of China included HFMD into the notifiable disease category and managed it as a Category C infectious diseases.Since then,the incidence of HFMD in China has been rising year by year.From 2008 to 2018,the incidence rate increased from37.6/10 million to 169.4/10 million,always ranking first in the Category C infectious disease,which has caused huge economic and disease burden and has been one of the major public health problems in China.Nowadays,many studies have shown that the case number and incidence rate of HFMD display an obvious seasonal fluctuations in time,and this seasonal fluctuation is closely related to meteorological factors,including average daily temperature,average daily relative humidity,average daily wind speed,daily sunshine hours,and average daily air pressure,indicating that meteorological factors play an important role in the occurrence and spread of the epidemic.However,China has a vast territory,spanning multiple latitudes and longitudes,and a variety of climate types,but previous studies mostly focused on the humid and semi-humid areas in eastern China,and few on inland arid areas in northwest China.Since the climatic conditions in different regions differ,so do the economic development level and medical service capacity,and the impact of meteorological factors on the incidence of HFMD in the arid northwest China is also different.What's more,previous studies mostly used weekly or monthly incidences,and the time scales were chosen in a relatively broad manner,with correlation analysis,regression analysis and other methods employed to explore the relationship between the meteorological factors and the spread of HFMD,not considering that the influence of meteorological factors on the incidence of HFMD is not only non-linear,but also lagging.In recent years,as global warming deepens,the temperature of Jiayuguan City,located in the arid northwest China,has been rising faster than expected,and the incidence of HFMD has increased compared with the past.Therefore,it is necessary to conduct a preliminary study on the epidemiological characteristics of HFMD in Jiayuguan City and the relationship between meteorological factors and the incidence of HFMD,explore the major meteorological factors affecting the occurrence and spread of HFMD,and reveal the epidemiological change trend of HFMD,so as to provide a theoretical basis for the local department to develop prevention and control measures for HFMD.Research methodologyCollect the data of HFMD in children aged 0¹4 in Jiayuguan City from January1,2008 to December 31,2018 from the“Infectious Disease Report Information Management System”in the“China Information System for Disease Prevention and Control”;Collect meteorological data of Jiayuguan City during the same period from Gansu Meteorological Bureau,including average daily temperature,average daily relative humidity,average daily wind speed,daily sunshine hours and average daily air pressure;and obtain the demographic data from Gansu Statistical Yearbook.First of all,with the descriptive epidemiology method,the characteristics of time change,population distribution and spatial distribution of HFMD cases in children aged 0¹4 in Jiayuguan City during the study period were analyzed.Secondly,Spearman rank correlation was used to analyze the correlation among various meteorological factors,so as to determine the meteorological variables to be included in the model.The distributed lag nonlinear model?DLNM?based on Poisson distribution was adopted to establish models for each meteorological factor,to discuss the nonlinear and lagging effects of each meteorological factor on the incidence of HFMD were discussed.Meanwhile,the effects of different percentiles(P₅,P₂₅,P₇₅,P₉₅)of common meteorological factors on the incidence of HFMD in children under different lagging days were calculated.Stratified by gender,age and season,the risk effects of the above meteorological factors were further analyzed.Research results?1?Descriptive analysis:The incidence of HFMD in children aged 0¹4 years in Jiayuguan City from 2008 to 2018 showed an obvious seasonal fluctuation.The first peak occurred in April to July,and the second peak occurred in October to November.Among the reported cases of HFMD in children,the incidence of boys is higher than that of girls?1.45:1?;the incidence age was mainly concentrated in the 0⁵ year-old group,accounting for 74.07%of the reported cases;The HFMD-hit population was mainly childrencare kids,accounting for 57.85%of reported cases.The incidence of HFMD in children showed no obvious aggregation tendency in spatial distribution,in a sporadic state.?2?The overall correlation between various meteorological factors and the incidence of HFMD in children:Using the median of each meteorological factor as a reference value and fitting through the DLNM model,a 3D effect plot of the impact of each meteorological factor on the incidence of HFMD in different lagging days was obtained.There is a non-linear relationship between each meteorological factor and the daily incidence number,and the relative risks and hysteresis effects of different meteorological factors are different.When the average daily temperature is 20.0?,and the RR value is the maximum when the number of the lagging day is 0,and it's1.238?95%CI:1.126¹.362?;when the average daily relative humidity is 24.0%,the RR value is the maximum when the number of the lagging day is 7,and it's1.172?95%CI:1.102¹.247?;when the average daily wind speed is 4.0m/s,the RR value is the maximum when the number of the lagging day is 1,and it's 1.280?95%CI:1.130¹.450?;when the daily sunshine hours is 2.0h,the RR value is the maximum when the number of the lagging day is 1,and it's 1.443?95%CI:1.207¹.725?;when the average daily air pressure is 846.0hPa,the RR value is the maximum when the number of the lagging day is 0,and it is 1.214?95%CI:1.094¹.348?.?3?Exposure response curves of various meteorological factors and HFMD in children are as follows:There is a non-linear exposure response relationship between various meteorological factors and the incidence of HFMD in children,but the specific exposure response curves have different shapes.The average daily temperature,relative humidity and air pressure showed an“M”shape to the incidence of HFMD in children,the average daily wind speed an irregular“W”shape,and the daily sunshine hours an“N”shape.When the average daily temperature is in the range of-5.0?⁰.0?and 10.0?²5.0?,the RR value is greater than 1,and it reaches the maximum at 19.0?;When the average daily relative humidity is in the range of 15.0%⁴0.0%and 50.0%⁷9.0%,the RR value is greater than 1,and the RR value reaches the maximum at 27.0%;The daily average wind speed shows a harmful effect when it is 2.0m/s⁴.0m/s,and the RR value reaches the maximum when it is3.0m/s;When the daily sunshine hours range from 1.0h⁶.0h and 10.0h¹4.0h,and the RR value is greater than 1,and at 14.0h the RR value reaches the maximum;The average daily air pressure shows a harmful effect when it's within 845.0hPa⁸51.9hPa,and reaches the maximum harmful effect when it is 847.0hPa.?4?Simple effects of various meteorological factors on the incidence of HFMD in children are as follows:At different percentiles of the average daily temperature,namely,P₅?-11.3??,P₂₅?-1.7??,P₇₅?19.0??and P₉₅?24.2??,the average daily temperature shows a harmful effect on the incidence of HFMD in children after zero lagging day?Lag0d?.When the average daily temperature is 19.0??Lag0d?,the RR value is the maximum,that is,1.231?95%CI:1.245¹.348?;At different percentiles of the average daily relative humidity,namely,P₅?21.0%?,P₂₅?33.0%?,P₇₅?56.0%?,P₉₅?76.7%?,the risk of relative humidity has to the incidence of HFMD in children reaches the highest when the number of lagging day is 7?Lag7d?,and the RR value reaches the maximum?RR=1.167,95%CI:1.095¹.242?when the average relative humidity is 21.0%?Lag7d?;At different percentiles of the average daily wind speed,namely,P₅?1.3m/s?,P₂₅?1.7m/s?,P₇₅?2.5m/s?,P₉₅?3.9m/s?,the risk of the HFMD incidence is not consistently changing with the lagging days,and when the average daily wind speed is 3.9m/s?Lag1d?,the RR value is the maximum,that is,1.277?95%CI:1.133¹.439?;At different percentiles of the daily sunshine hours,namely,P₅?0.0h?,P₂₅?7.1h?,P₇₅?11.0h?,P₉₅?13.3h?,the risk of sunshine hours on the incidence of HFMD in children varies with the number of lagging days,and when the average daily sunshine hour is 0.0h?Lag1d?,the RR value is the maximum,that is,1.289?95%CI:1.049¹.585?;At different percentiles of the average daily air pressure,namely,P₅?843.2hPa?,P₂₅?847.9hPa?,P₇₅?856.2hPa?,P₉₅?861.9hPa?,air pressure shows harmful effects on the incidence of HFMD in children on Lag0d,and when the average daily air pressure is 847.9hPa?Lag0d?,the RR value is the maximum,that is,1.184?95%CI:1.091¹.285?.?5?The cumulative effects of various meteorological factors on the incidence of HFMD in children are as follows:When the temperature is-1.7?,the cumulative hysteresis effect of HFMD in children is statistically significant from lag0⁵d to lag0⁷d,and the cumulative effect RR value reaches the maximum when Lag0⁵d?RR=1.444,95%CI:1.066¹.955?.When the temperature is 19.0?,the cumulative hysteresis effect of HFMD in children is statistically significant throughout the hysteresis period,and the cumulative effect RR value reaches the maximum at Lag0⁷d?RR=2.632,95%CI:2.239³.094?;When the relative humidity is 21.0%,the cumulative effect RR value is statistically significant at Lag0⁷d and reaches the maximum value?RR=1.900,95%CI:1.590².270?;When the wind speed is 3.9m/s,the cumulative hysteresis effect of HFMD in children is statistically significant from Lag0¹d to Lag0⁷d,and the cumulative effect RR value reaches the maximum at Lag0⁷d?RR=2.056,95%CI:1.419².978?;When the sunshine hours is 13.3h,the cumulative hysteresis effect of HFMD in children is statistically significant from Lag0³d to Lag0⁷d,and the cumulative effect RR value reaches the maximum at Lag0⁷d?RR=2.601,95%CI:1.924³.516?;When the air pressure is 847.9hPa,the cumulative lagging effect of HFMD in children shows statistical significance throughout the lagging period,and the cumulative effect RR value reaches the maximum at Lag0⁷d?RR=1.886,95%CI:1.546².301?.?6?The impact of various meteorological factors on the incidence of HFMD in children of different genders and ages:Daily average temperature changes can increase the incidence of HFMD in children,and boys and adolescents of 6¹4 years old are more susceptible to temperatures;Relative humidity has a greater impact on the harmful effects of boys and 0⁵-year-old children than other subgroups.Boys and0⁵-year-old children are more sensitive to changes in relative humidity;With the increase of the average daily wind speed,the risk of HFMD in children also increases.Boys and adolescents of 6¹4 year old are more susceptible to changes in wind speed;Longer sunshine hours will increase the risk of the incidence of HFMD in children,and boys and 0⁵-year-old children are more susceptible to changes in sunshine hours;The decline of the average daily air pressure can increase the risk of the incidence of HFMD in children,and boys,together with 0⁵-year-old children are more susceptible to changes in air pressure.?7?The influences of various meteorological factors on the incidence of HFMD in children in different seasons are as follows:The average daily temperature shows greater impacts on the incidence of HFMD in children in spring and summer than in autumn and winter;The impact of the average daily relative humidity on the incidence of HFMD in children is greater in spring and lower in winter;The impact of daily average wind speed on HFMD in children is significantly higher in spring than in other seasons;the daily sunshine hours show obvious influences on the incidence of HFMD in children in winter and less in summer;The average daily air pressure also has a greater impact on HFMD in children in winter,and less in summer.Conclusions?1?The incidence of HFMD in children in Jiayuguan City showed two peaks?April-July and October-November?.The reported cases were mainly boys,0⁵-year-old children and childrencare children.At the same time,the incidence demonstrated no obvious clustering trend in spatial distribution,but a sporadic state.?2?Various meteorological factors have a non-linear effect on the incidence of HFMD,and the exposure response curves are diversely shaped.Temperature,relative humidity,wind speed,sunshine hours,and air pressure all display impacts on the incidence of HFMD in children within a specific range or interval,and the hysteresis effect exists.?3?In terms of simple effects,temperature,relative humidity,wind speed,sunshine hours,and air pressure demonstrate different effects on the incidence of HFMD in children with different lagging days and different percentiles.Therefore,the corresponding specific RR values also differ.As for cumulative effects,the cumulative effects RR values of the above meteorological factors on the incidence of HFMD in children are also different,and the lagging time where the maximum effect value appears is mainly Lag0⁷d.?4?Various meteorological factors have different effects on the incidence of HFMD in children of different genders and ages,and children of different genders and ages have different degrees of sensitivity to changes in various meteorological factors.In addition,there are obvious seasonal differences in the impact of various meteorological factors on the incidence of HFMD in children,and the effect values of spring,summer,autumn and winter differ.