title: Are periods of low atmospheric pressure associated with an increased risk of abdominal aortic aneurysm rupture?
abstract: BACKGROUND
  Seasonal variation in rates of abdominal aortic aneurysm (AAA) rupture has previously been described. However, only two studies, to date, have suggested that periods of low atmospheric pressure may account for this observation and both returned apparently contradictory findings. The objective of this study was to demonstrate whether periods of low atmospheric pressure are indeed associated with an increased likelihood of AAA rupture presentation.
  
  
  METHODS
  A total of 182 cases of ruptured AAA were identified retrospectively from two centres over a 6-year period from January 2000 to December 2005. Local meteorological data for the corresponding period was obtained from the UK Meteorological Office which was recorded daily at a local weather station. Statistical analysis using Student's t-test, ANOVA (Kruskal-Wallis), linear regression and multiple logistic regression was conducted to identify significant relationships from the data.
  
  
  RESULTS
  Days of rupture presentation were associated with a significantly lower daily mean atmospheric pressure when compared with days when no rupture occurred (P = 0.025). Multiple logistic regression demonstrated a significant association between low daily atmospheric pressure and rupture incidence (P = 0.033) which appeared to be independent of temperature. A significant seasonal trough in atmospheric pressure was observed in October and November (Kruskal-Wallis, P < 0.001); however, there was no corresponding autumnal peak in rupture incidence (P = 0.232).
  
  
  CONCLUSIONS
  The findings of this study appear to confirm the assertion that low atmospheric pressure is associated with an increased risk of AAA rupture on a day-to-day basis; however, no evidence was identified to support a change in policy regarding prioritising elective surgery based on seasonal risk.
authors.affiliation: Department of Surgery, Royal Liverpool University Hospital, Liverpool, UK. richsmith@doctors.org.uk
authors.forename: R A
authors.initials: RA
authors.lastname: Smith
authors.forename: P R
authors.initials: PR
authors.lastname: Edwards
authors.forename: A F
authors.initials: AF
authors.lastname: Da Silva
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D017544:Aortic Aneurysm, Abdominal / Q000209:etiology* / Q000601:surgery; D001019:Aortic Rupture / Q000209:etiology* / Q000601:surgery; D001274:Atmospheric Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D014887:Weather