The Effects Of Meteorological Factors And Air Pollutants On The Risk Of Influenza In Jinan City

Research backgroundInfluenza is an acute respiratory infectious disease caused influenza virus.Pregnant women,infants,the elderly,and patients with chronic underlying diseases are high-risk groups.Influenza and SARS-CoV-2 infection are both respiratory infectious diseases.In terms of high incidence season,transmission route,and susceptible population,the epidemic situation of influenza and SARS-CoV-2 infection pneumonia is similar.The co-infection of influenza and novel coronavirus pneumonia can lead to a more intense inflammatory response,aggravation of illness,prolonged course of the disease,and higher fatality rate.The global outbreak and spread of SARS-CoV-2 infection have delivered a severe challenge to the world.Our country has now successfully emerged from the SARS-CoV-2 pandemic,but it has not disappeared,and the epidemic is still in the state and local sporadic throughout the country.Therefore,the significance of influenza prevention and control is particularly important.Meteorological factors and air pollutants are often the predisposing factors for the spread of infectious diseases.Some studies have shown air pollution is strongly associated with many respiratory diseases and cardiovascular and cerebrovascular diseases,such as asthma,acute respiratory distress syndrome,and respiratory infection.Influenza is one of the major global public health problems,and some experts and scholars have also studied the impact of meteorological factors and air pollutants.However,in the face of the COVID-19 pandemic and the differences in economic conditions and social environments in different regions,previous studies cannot replace those in Jinan City.Research purpose(1)To describe the three spatial distribution characteristics of influenza cases in Jinan city from 2020 to 2021;(2)To explore the nonlinear effect and threshold effect of meteorological factors and air pollutants on the risk of influenza;(3)To investigate the lag effect and cumulative lag effect of meteorological factors and air pollutants on the risk of influenza in Jinan,and to identify the vulnerable population;(4)To provide references for the prevention and control of influenza in Jinan and improve the prevention and control level of influenza in Jinan through research.Research method1.Sources of dataThe concentrations of air pollutants,including PM2.5,PM10,SO2,CO,NO2,and O3,were collected between 1 January 2020 and 31 December 2021,from the Air Quality Online Monitoring and Analysis Platform of China.The daily mean temperature,mean relative humidity and mean wind speed of Jinan were obtained from the Weather of the World during the study period.2.Statistical analysis(1)First,descriptive analysis was conducted on influenza in Jinan during 2020-2021 to obtain its three distribution characteristics.Influenza,meteorological,and pollutant concentration data were cleaned and sorted into daily scale time series data.Spearman correlation was used to analyze the correlation between influenza and meteorological factors、pollutants.(2)The distribution lag nonlinear model(DLNM)was used to establish models of meteorological factors and pollutants respectively.When discussing a meteorological factor on influenza risk,other meteorological factors were included in the model as control variables to discuss the nonlinear effect of meteorological factors on influenza risk,and meteorological nodes and data nodes were selected to study the effect.The distribution lag nonlinear model(DLNM)was used to investigate the nonlinear effect of atmospheric pollutants on the risk of influenza,and meteorological factors were included as covariables to control the model.The GAM model was used to investigate the lag effect and cumulative lag effect of increasing pollutant concentration of 10μg/m3(CO:0.1mg/m3)on the risk of influenza.(3)In the study of meteorological factors and atmospheric pollutant concentration on the incidence of influenza in Jinan,the whole population was divided into male and female by sex,and 0-6 years old,7-18 years old,19-59 years old,60 years old and above.The total effect of meteorological factors on the risk of influenza in each subgroup and the effect of air pollutant concentration increasing by 10 μg/m3(CO:0.1mg/m3)on the risk of influenza in each subgroup were investigated.(4)This study conducted a sensitivity analysis of the results and explored the reliability of changing the degree of freedom(6-9)of the time trend.Research results1.From January 1,2020,to December 31,2021,a total of 4767 clinically diagnosed and confirmed cases were reported in the influenza surveillance system in Jinan.During the study period,December-February was the main peak of influenza cases,and in June and July 2021,influenza cases showed a secondary peak.There was no significant difference in the number of cases between men and women.Among the age groups,the number of cases in 0-6 years old was the largest,with a total of 2115 cases,accounting for 44.37%of the whole population.In terms of regional distribution,the number of influenza cases in Lixia District and Huaiyin District was higher than in other districts in the past two years.2.From 2020 to 2021,the average concentrations of PM2.5,PM10,and O3 in Jinan City all reach the second-level reference value of pollutant concentration prescribed by our country.While SO2,NO2,and CO all reach the first-level reference value of pollutant concentration prescribed by the WHO(World health organization).3.The fluctuation of meteorological factors and the concentration of air pollutants over time has a certain rule.Except for O3,the concentration of air pollutants fluctuates the same with time changes,while O3 concentration fluctuates the opposite.4.The Effects of meteorological factors on the risk of influenzaDuring the study period,the effect values of temperature,wind speed,and relative humidity on the risk of influenza were not high,and the number of influenza cases was negatively correlated with temperature and wind speed,but positively correlated with relative humidity.The lower relative humidity is dangerous to influenza,higher relative humidity is protective to influenza.In the study of different meteorological factors on the risk of influenza,the results show that the extremely lower temperature lag7 days,the extremely low wind speed lag4 days,and the extremely low relative humidity lag7 days have a dangerous effect on the risk of influenza.Different meteorological factors on influenza on a certain date were studied.The results showed that low temperature had a dangerous effect on the occurrence of influenza at lag3 days and lag7 days,the low wind speed had a dangerous effect on the occurrence of influenza at lag3 days and low relative humidity had a dangerous effect on the incidence of influenza at lag1 days and lag7 days.Subgroup results showed that different meteorological factors had different effects on the risk of influenza in different populations.Lower temperature and lower relative humidity had the greatest effect on the risk of influenza in the age group of 60 years and above,and lower relative humidity had the risk effect on the incidence of influenza in the age group of 7-18 years.5.The effects of air pollutants on the risk of influenzaThe effects of pollutants on the risk of influenza in different populations showed that except for O3,the risk of influenza increased with the increase of pollutant concentration.The time and effect of increasing pollutant concentration of 10μg/m3(CO:0.1mg/m3)on the risk of influenza in different populations were inconsistent,and the effect of gaseous pollutants(NO2,SO2)was greater than that of particulate pollution(PM10,PM2.5).Subgroup results showed that increased concentrations of PM10 and SO2 had the highest cumulative risk for influenza morbidity in men than in women,and increased concentrations of PM2.5,NO2,and CO had the highest cumulative risk for influenza morbidity in women than in men.Age group results showed:The delay time of the dangerous effect of pollutant concentration changes on the incidence of influenza in different groups is inconsistent.The results of different age groups show that PM2.5,PM10,SO2,and NO2 increase by 10ug/m3 has the greatest impact on the incidence of influenza in the age group 60 and above,and the change of CO concentration has the greatest impact on the incidence of influenza in the age group 19-59.Research conclusion1.The fluctuation of influenza epidemic cases is roughly consistent with the fluctuation of meteorological factors and air pollutants.The peak of influenza incidence occurs from December to February every year,and a small peak of influenza incidence occurs in May,June,and July of 2021.2.There is no significant difference between the sexes,and the number of cases in the age group 0-6 years old is relatively large,which may be related to the incomplete development of the immune system of people in the younger age group,weak immunity and poor ability to resist the virus.3.Temperature and wind speed were negatively correlated with the risk of influenza,and the temperature on the risk of influenza was weakened during the epidemic.Different meteorological factors had different effects on the risk of different subgroups.Low temperature,lower wind speed,and low humidity had greater effects on the risk of influenza in the higher age group,while high wind speed and high relative humidity showed protective effects.4.The risk lag time and the effective value of pollutant concentration changes in different populations are inconsistent.Gaseous pollutants(NO2,SO2)have a higher risk of influenza than particulate pollutants,and people aged 60 and above have a greater excess risk of influenza when exposed to pollutants.O3 was negatively associated with the risk of influenza.