title: Association of environmental factors with the onset of status epilepticus.
abstract: OBJECTIVE
  The goal of the work described here was to investigate the influence of environmental factors on admissions of patients with status epilepticus (SE) to the intensive care unit (ICU).
  
  
  METHODS
  This retrospective cohort study analyzed all admissions to a university hospital ICU because of SE. Poisson regression and likelihood ratio tests were employed to determine associations between environmental factors and the incidence of SE.
  
  
  RESULTS
  Data on 184 patients (mean age: 57, range: 18-89) indicated a significant (P<0.0001) diurnal pattern, with admissions peaking between 4 and 5 PM and reaching a minimum in the early morning. No significant weekly, monthly, or seasonal pattern was observed. Admissions varied significantly across the lunar cycle (P=0.003), peaking at Day 3 after new moon and being minimal 3 days before new moon. The incidence of SE increased on bright days (P=0.04) and with the duration of daily sunshine (P=0.03). High relative humidity (P<0.01), high temperature (P<0.05), and dark days (P=0.02) were significantly protective factors. The incidence of SE on weekends was significantly lower in the subgroup of patients with known epilepsy (P=0.004), and the risk of nonconvulsive SE was significantly higher in summer (P=0.04).
  
  
  CONCLUSIONS
  Admissions of patients with SE to the ICU are significantly associated with several environmental protective and precipitating factors, such as diurnal, weekly, and lunar cycles and weather variables.
authors.affiliation: Division of Clinical Neurophysiology, Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. srueegg@uhbs.ch
authors.forename: Stephan
authors.initials: S
authors.lastname: Rüegg
authors.forename: Patrick
authors.initials: P
authors.lastname: Hunziker
authors.forename: Stephan
authors.initials: S
authors.lastname: Marsch
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004777:Environment; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data*; D010507:Periodicity; D012189:Retrospective Studies; D013226:Status Epilepticus / Q000453:epidemiology*