title: Effect of preadmission sunlight exposure on intensive care unit-acquired delirium: a multicenter study.
abstract: OBJECTIVE
  It is assumed that there is a relation between light exposure and delirium incidence. The aim of our study was to determine the effect of prehospital light exposure on the incidence of intensive care unit (ICU)-acquired delirium.
  
  
  METHODS
  Data from 3 ICUs in the Netherlands were analyzed retrospectively. Delirium was assessed with the Confusion Assessment Method for the ICU. Daily light intensity data were obtained from meteorological stations in the vicinity of the 3 hospitals. The association between light intensity and delirium incidence was analyzed using logistic regression analysis adjusting for known covariates for delirium.
  
  
  RESULTS
  Data of 3198 patients, aged (mean ± SD) 61.9 ± 15.3 years with Acute Physiology and Chronic Health Evaluation II score 16.4 ± 6.6 were analyzed. Delirium incidence was 31.2% and did not vary significantly throughout the year. Twenty-eight-day preadmission photoperiod was highest in spring and lowest in winter; however, no association between light exposure and delirium incidence was found (odds ratio, 1.00; 95% confidence interval, 0.99-1.00; P = 0.72). Furthermore, delirium was significantly associated with age, infection, use of sedatives, Acute Physiology and Chronic Health Evaluation II score, and diagnosis of neurological disease or trauma.
  
  
  CONCLUSIONS
  The incidence of delirium does not differ per season and prior sunlight exposure does not play a role of importance in the development of ICU-acquired delirium.
authors.affiliation: Department of Intensive Care Medicine, Jeroen Bosch Ziekenhuis, 's-Hertogenbosch, the Netherlands; Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. Electronic address: k.simons@jbz.nl.
authors.forename: Koen S
authors.initials: KS
authors.lastname: Simons
authors.affiliation: Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. Electronic address: j.d.workum@cukz.umcn.nl.
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Workum
authors.affiliation: Department of Intensive Care Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands. Electronic address: a.slooter-3@umcutrecht.nl.
authors.forename: Arjen J C
authors.initials: AJ
authors.lastname: Slooter
authors.affiliation: Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. Electronic address: m.vandenboogaard@ic.umcn.nl.
authors.forename: Mark
authors.initials: M
authors.lastname: van den Boogaard
authors.affiliation: Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. Electronic address: j.vanderhoeven@ic.umcn.nl.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: van der Hoeven
authors.affiliation: Department of Intensive Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. Electronic address: p.pickkers@ic.umcn.nl.
authors.forename: Peter
authors.initials: P
authors.lastname: Pickkers
mesh_terms: D000328:Adult; D000367:Age Factors; D003693:Delirium / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects; D015994:Incidence; D007239:Infections / Q000150:complications; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D016017:Odds Ratio; D012044:Regression Analysis; D012189:Retrospective Studies; D012621:Seasons; D013472:Sunlight
chemical_list: D006993:Hypnotics and Sedatives
keywords: Association; Critically ill; Delirium; Intensive care; Photoperiod; Sunlight exposure