Association Between Meteorological Factors And Hemorrhagic Stroke In Shenzhen

【Objective】By analyzing the correlation between new cases of hemorrhagic stroke in Shenzhen from 2008 to 2014 and meteorological environmental data in the same period,the study focuses on the impact of meteorological factors on the incidence of hemorrhagic stroke so as to screen out susceptible population and offer theoretical basis for disease control personnel to formulate public health strategies.【Methods】The study includes 21,810 new cases of hemorrhagic stroke in Shenzhen from 2008 to 2014 and all patients were aged 18 or above.The newly-issued hemorrhagic stroke data and the simultaneous meteorological data are described in time sequence.Through the calculation of the Spearman rank correlation coefficient,this study assesses the correlation between time and new cases of hemorrhagic stroke,and the mutual influence between meteorological factors.After the descriptive analysis of the patients and the meteorological environment,the distribution lag non-linear model is used to analyze the influence of meteorological factors on hemorrhagic stroke.The influence includes the one-day lag effect and cumulative lag effect of various meteorological factors.Finally,this study,through subgroup analysis,evaluates the population difference of lag effect.【Results】1.A total of 21,810 new cases of hemorrhagic stroke from 2008 to 2014in Shenzhen were included in this study.Through the Spearman grade correlation analysis,the new cases of hemorrhagic stroke showed an upward trend year by year.During the same period,the number of new cases among men was more than that among women,and the proportion of male cases increased year by year.With the increase of age,the incidence of hemorrhagic stroke increases gradually.2.Spearman correlation coefficient is used to describe the correlation between meteorological factors.Results are listed as follows:there is a highly negative correlation between the daily average air pressure and the daily average temperature(=-0.854,P<0.0001),and there is a certain correlation between other meteorological factors,but the correlation is weak(<0.5).3.Results of single factor model analysis:（1）One-day lag effect.High relative humidity,low temperature,and low relative humidity all presented dangerous effects.The RR values of the maximum effect are listed as follows:RR=1.040,95%CI:1.004～1.078;RR=1.041,95%CI:1.002～1.081;RR=1.142,95%CI:1.052～1.240.Low pressure and low wind speed all showed protective effects,and the RR values of the maximum effect are presented as follows:RR=0.889,95%CI:0.806～0.980;RR=0.943,95%CI:0.894～0.996.（2）Cumulative lag effect.Low temperature will increase the risk of people having hemorrhagic stroke.As the temperature increases,it gradually presents a protective effect.Low pressure has protective effects on hemorrhagic stroke.Relatively high or low humidity may increase the risk for people to have hemorrhagic stroke.There is no statistical significance to take the influence of wind and sunshine into consideration.4.Multi-factor model analysis results:（1）One-day lag effect.Both low temperature and low relative humidity present dangerous effects.The RR values of the maximum effect are listed as follows:RR=1.072,95%CI:1.005～1.143;RR=1.181,95%CI:1.076～1.297.The RR value gradually decreases with the increase of lag days.（2）Cumulative lag effect.The RR value of air temperature gradually decreases with the increase of temperature.Low temperature presents the dangerous effect when the lag days are few while high temperature presents the protective effect.The results of the changing air pressure and relative humidity are basically consistent with the results of the single factor model.5.Subgroup analysis results:The cumulative lag effect of high temperature on male,female and young and middle-aged groups showed protective effect.Low temperature has a dangerous effect on men.It is suggested that low temperature has great influence on men.High pressure has protective effects on female,young and middle-aged groups.High relative humidity has dangerous effects on female,young and middle-aged groups.Low relative humidity has dangerous effects on male,female,young and middle-aged groups.【Conclusion】The number of new cases of hemorrhagic stroke in Shenzhen increased year by year from 2008 to 2014.There is a highly negative correlation between the daily average air pressure and the daily average temperature.Low pressure,high pressure high temperature and low wind speed reduce the risk of hemorrhagic stroke.Low temperature and low or high relative humidity increase the risk of hemorrhagic stroke.In terms of the impact of short-term exposure to meteorological factors on hemorrhagic stroke,women and the elderly are more sensitive to changes of air pressure,and the elderly are more sensitive to high relative humidity.Therefore,active protection in extreme weather conditions is of great public health significance to prevent or reduce the incidence of hemorrhagic stroke in sensitive populations.