title: Meteorological influences on the incidence of aneurysmal subarachnoid hemorrhage - a single center study of 511 patients.
abstract: OBJECTIVE
  To assess the potential meteorological influence on the incidence of aneurysmal subarachnoid hemorrhage (SAH). Previous studies used inhomogeneous patient groups, insufficient study periods or inappropriate statistics.
  
  
  METHODS
  We analyzed 511 SAH admissions between 2004 and 2012 for which aneurysmal rupture occurred within the Zurich region. The hourly meteorological parameters considered are: surface pressure, 2-m temperature, relative humidity and wind gusts, sunshine, and precipitation. For all parameters we investigate three complementary statistical measures: i) the time evolution from 5 days before to 5 days after the SAH occurrence; ii) the deviation from the 10-year monthly mean; and iii) the change relative to the parameter's value two days before SAH occurrence. The statistical significance of the results is determined using a Monte Carlo simulation combined with a re-sampling technique (1000×).
  
  
  RESULTS
  Regarding the meteorological parameters considered, no statistically significant signal could be found. The distributions of deviations relative to the climatology and of the changes during the two days prior to SAH events agree with the distributions for the randomly chosen days. The analysis was repeated separately for winter and summer to exclude compensating effects between the seasons.
  
  
  CONCLUSIONS
  By using high-quality meteorological data analyzed with a sophisticated and robust statistical method no clearly identifiable meteorological influence for the SAH events considered can be found. Further studies on the influence of the investigated parameters on SAH incidence seem redundant.
authors: University Hospital Zurich, Department of Neurosurgery, Zurich, Switzerland.
authors: Marian Christoph
authors: MC
authors: Neidert
authors: Michael
authors: M
authors: Sprenger
authors: Heini
authors: H
authors: Wernli
authors: Jan-Karl
authors: JK
authors: Burkhardt
authors: Niklaus
authors: N
authors: Krayenbühl
authors: Oliver
authors: O
authors: Bozinov
authors: Luca
authors: L
authors: Regli
authors: Christoph Michael
authors: CM
authors: Woernle
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002980:Climate; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008685:Meteorological Concepts; D008875:Middle Aged; D009010:Monte Carlo Method; D012189:Retrospective Studies; D012621:Seasons; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology*; D013997:Time Factors; D055815:Young Adult