DLNM Model Was Used To Analyze The Correlation And Lag Effect Between The Number Of Admissions With Spontaneous Intracerebral Hemorrhage And Meteorological Factors In Nanchong City

Objective:To study the relationship between spontaneous intracerebral hemorrhage(ICH)risk and temperature and air pressure as well as the lag effect of its in Nanchong City.Methods:Data on patients with ICH admitted to the second-class grade hospitals or above,daily temperature,and air pressure in Nanchong City from January 1,2014 to December 31,2020 were collected.Spearman rank correlation method was adopted to assess the association between different temperatures and air pressures and the number of dailyadmissions for ICH.The distributed lag non-linear model(DLNM)package in R software(2.4.2)was applied to analysis air temperature,air pressure,and the number of ICH jointly.Results:1.A total of 20779 eligible patients admitted to the hospital due to ICH,involving 12,393 males and 8386 femes,with a ratio of 1.48:1,were included.There were 6644 cases in the younger group aged 18-60 years and 14135 cases in the elderly group aged over 60 years,with a ratio of 2.13:1.In spring and winter,11236 cases were identified and in summer and autumn,there were 9543 cases,with a ratio of 1.2:1.Results indicated that the incidence of ICH was more often with elderly age and male gender.Further analysis showed that the number of daily admissions was much higher in spring and winter than in summer and autumn.2.In our study,we found that an inverse relationship between average daily temperature and ICH admissions and the average,optimum,and daily temperature(defined as inflection point temperature,IPT)was 24?.When the average daily temperature was less than 24?,the daily average temperature showed a harmful effect on the incidence of ICH.The relative risk(RR)estimates were 1.52(1.29-1.79)and 1.34(1.18-1.51)for the extremely low temperature(4.0?)and low temperature(7.9?)on the same day.There was no significant association between the number of daily admissions and high temperature(28.5?,RR:0.95,95%CI:0.89-1.01)and extremely high temperature(33.2?,RR:0.88,95%CI:0.77-1.00)on the same day.Below the IPT,no significant association was observed for the extremely low temperature(RR:1.05,95%CI:0.98-1.14)and low temperature(RR:1.03,95%CI:0.97-1.10)after 2 days of lag.Further analysis stratified by gender and age showed that below the IPT,similar findings with overall results were identified.3.Results showed that there was no significant association betweenair pressure and the number of daily admissions.The RRs with corresponding 95%CIs were 0.87(0.61-1.22),0.80(0.57-1.13),0.84(0.60-1.17),and 0.76(0.57-1.03)for extremely low air pressure(960.8Hpa),low air pressure(966.2Hpa),high air pressure(988.1Hpa),and extremely high air pressure(994.4Hpa)on the same day,respectively.Further analysis suggested that there was no obvious lag effect of air pressure on daily admissions.Conclusion:1.The incidence of spontaneous cerebral hemorrhage was more often with elderly age and male gender.2.The temperature was inversely associated with the number of hospitalized patients with ICH,and the lag effect of low temperature exists for 2 days.3.There was no significant association between air pressure and daily admissions with ICH and no lag effect was identified.