title: A High-Resolution Analysis on the Meteorological Influences on Spontaneous Intracerebral Hemorrhage Incidence.
abstract: OBJECTIVE
  To investigate the influence of meteorological factors on the incidence of intracerebral hemorrhage (ICH).
  
  
  METHODS
  We included 295 ICH admissions between 2005 and 2013. The hourly meteorological parameters considered were surface pressure, temperature, relative humidity, wind gusts, and precipitation. To minimize confounding effects of seasonality, data were analyzed with the following 3 complementary statistical approaches: 1) deviation of daily measure from the 10-year monthly mean at the day of ictus; 2) deviation from monthly average with respect to changes in daily measures between the day of ictus and 2 days before; and 3) evolution of daily measures from 5 days before to 5 days after the ICH occurred. For 1) and 2), the statistical significance of the results was determined with a Monte Carlo simulation combined with a resampling technique (1000×).
  
  
  RESULTS
  Regarding all patients, no statistically significant and meteorologically meaningful signal could be found. With respect to subgroup-analysis, ICH related to vascular pathologies occurred significantly more frequently at days with especially low relative humidity, whereas an opposite relation was present in patients with cerebral amyloid angiopathy. However, as absolute deviations were small, a strong functional effect is questionable. With respect to seasonal distribution, a greater incidence of ICH could be detected during the cold season, in line with previous reports.
  
  
  CONCLUSIONS
  By using high-quality meteorological data analyzed with a sophisticated and robust statistical method that minimizes the confounding effect of seasonality, no clearly identifiable meteorological influence for the ICH events considered can be found.
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland. Electronic address: marian.neidert@usz.ch.
authors.forename: Marian Christoph
authors.initials: MC
authors.lastname: Neidert
authors.affiliation: Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Sprenger
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland.
authors.forename: Marius
authors.initials: M
authors.lastname: Mader
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Esposito
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland; Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zurich, Zurich, Switzerland.
authors.forename: Jonas Aurel
authors.initials: JA
authors.lastname: Hosp
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bozinov
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Regli
authors.affiliation: Department of Neurosurgery, University of Zurich, Zurich, Switzerland.
authors.forename: Jan-Karl
authors.initials: JK
authors.lastname: Burkhardt
mesh_terms: D002543:Cerebral Hemorrhage / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012621:Seasons; D020521:Stroke / Q000453:epidemiology; D013557:Switzerland / Q000453:epidemiology; D014887:Weather
keywords: Hemorrhagic stroke; ICH; Intracerebral hemorrhage; Meteorology; Weather