title: Association between hemorrhagic stroke occurrence and meteorological factors and pollutants.
abstract: BACKGROUND
  The purpose of this study is to determine whether intracerebral hemorrhage and subarachnoid hemorrhage have different incidence patterns based on monthly variations in meteorological and air pollution parameters in the Seongdong district of Seoul, South Korea.
  
  
  METHODS
  From January 1, 2004 to December 31, 2014, 1,477 consecutive hemorrhagic stroke events (>19 years old) were registered among residents of the Seongdong district, Seoul, South Korea. The authors calculated the relative risk of hemorrhagic stroke and its subtype incidence based on meteorological and air pollution factors. We also estimated relative risk with 95 % confidence intervals using a multivariate Poisson regression model to identify potential independent variables among meteorological factors and pollutants associated with either intracerebral hemorrhage or subarachnoid hemorrhage occurrence.
  
  
  RESULTS
  We observed a negative correlation between intracerebral hemorrhage and mean temperature. In the multivariate Poisson model, particulate matter with an aerodynamic diameter < 10 μm showed positive correlations with intracerebral hemorrhage (relative risk, 1.09; 95 % confidence interval, 1.02 to 1.15; P = 0.012). In contrast, ozone correlated significantly with subarachnoid hemorrhage occurrence (relative risk, 1.32; 95 % confidence interval, 1.10 to 1.58; P = 0.003).
  
  
  CONCLUSIONS
  Our findings show the relationship between hemorrhagic stroke and meteorological parameters and pollutants under similar weather and environmental conditions in a small area. Among meteorological and pollutant variables, only higher particulate matter concentrations correlated independently with intracerebral hemorrhage occurrence, while only ozone was independently associated with subarachnoid hemorrhage occurrence. These findings suggest the possibility that there are pathogenic associations between hemorrhagic stroke and meteorological factors and pollutants.
authors.affiliation: Department of Neurosurgery, Hanyang University Medical Center, 222 Haengdang-ro, Seoul, 133-792, South Korea.
authors.forename: Myung-Hoon
authors.initials: MH
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, Hanyang University Medical Center, 222 Haengdang-ro, Seoul, 133-792, South Korea. hjyi8499@hanyang.ac.kr.
authors.forename: Hyeong-Joong
authors.initials: HJ
authors.lastname: Yi
authors.affiliation: Department of Neurosurgery, Hanyang University Medical Center, 222 Haengdang-ro, Seoul, 133-792, South Korea.
authors.forename: Yong
authors.initials: Y
authors.lastname: Ko
authors.affiliation: Department of Neurosurgery, Hanyang University Medical Center, 222 Haengdang-ro, Seoul, 133-792, South Korea.
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Hanyang University Medical Center, Seoul, South Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Lee
mesh_terms: D000397:Air Pollution / Q000009:adverse effects*; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008685:Meteorological Concepts; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects; D056910:Republic of Korea / Q000453:epidemiology; D012306:Risk; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology*; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology* / Q000209:etiology*; D013696:Temperature; D014887:Weather
chemical_list: D052638:Particulate Matter
keywords: Air pollution; Hemorrhagic stroke; Intracerebral hemorrhage; Subarachnoid hemorrhage; Weather