The Associations Of Stroke Occurrence With Meteorological Factors And Air Pollution In Chengdu

Background and Objective：Stroke is one of the most common diseasesin the elder. It is the leading cause of death and disability in China. Thetemperature、relative humidity、sea-level atmospheric pressure、windspeed et are an important parts of the meteorological factors. Variousmeteorological factors interaction leads to the changes in the weather. Airpollution is more and more concerned in recent years. Many studies hadshown an association between meteorological factors or air pollution andstroke occurrence. Abnormally weather is a risk factor for stroke. But thetheory of association between meteorological factors、air pollution andstroke, which is need to make clear further study. By researching the linkbetween human health conditions, particularly stroke，and the weatherconditions、air pollution, peoples could arrange their working and leisurelife according to their individual conditions, which may in turn affectstroke risk. To investigate the impact of meteorological factors and airpollution on the onset of stroke in Chengdu area.Methods: The daily stroke data was obtained from the Sichuanprovincial people’s hospital register during2011-01-01to2011-12-31（Transient ischemic attack、 subarachnoid hemorrhage andintraventricular hemorrhage weren’t included in the analysis because small number of cases）. The daily meteorological parameters (includingmean relative humidity, maximum, minimum and sea-level atmosphericpressure and mean temperatures, maximum, minimum, and mean windspeed, maximum and dew point and Air pollution Index（API） ofChengdu were obtained from Chengdu Meteorological Bureau during2011-01-01to2011-12-31.This study used correlation analysis throughstatistical software SPSS For Windows17.0and SAS for Windows9.1toexplore the daily and weekly effects of meteorological parameters or airpollution levels. At last, the comfort index of human body(CIHB) asvariables Poisson regression model was fitted to estimate risk of stroke atdifferent levels of CIHBResults: The total number of patients was1131.291cases(25.7%) werecerebral hemorrhage，198cases were male.93cases were female;840cases(74.3%) were ischemic stroke，512cases were male,328cases werefemale.1. The incidence of cerebral infarction(CI) and intracerebralhemorrhage(ICH) was the highest in winter (the median daily count of CIin winter was2.82/day;and ICH in winter was0.96/day).The incidence ofCI was the lowest in autumn(the median daily count of CI in autumn was1.78/day); and ICH was the lowest in spring (the median daily count ofICH in spring was0.64/day. As the incidence of cerebral infarction(CI)and intracerebral hemorrhage(ICH) was higher in summer (the mediandaily count of ICH in winter was0.90/day;of IC in winter was2.30/day). 2Significant differences in seasonal and monthly patterns of stroke onsetwere observed. The incidence of stroke attack was higher in winterand in summer (p=0.0004). The monthly variation was consistentwith the above pattern (p <0.0001).3.The incidences of acutecerebrovascular disease had no relation with the changing of temperaturein twenty-four hours and API.4. We found a U-shaped relationshipbetween CI and comfort index of human body(CIHB), with the lowestrisk when CIHB for-1level,and the risks increased for the CIHB lowerthan-2level and higher than2level (P<0·05). We found a U-shapedrelationship between ICH and comfort index of human body(CIHB), withthe lowest risk when CIHB for1level,and the risks increased for theCIHB lower than-1level and higher than1level (P<0·05).Conclusion: The occurrence of stroke was obviously changed withdifferent season. The lower incidence of stroke was in serson which hadthe better suitable of CIHB. The incidence of stroke was higher insummer and winter which had more bad weather time. We concluded thatCIHB probably predict the risk of stroke.