title: U-shaped relationship between tissue docosahexaenoic acid and atrial fibrillation following cardiac surgery.
abstract: OBJECTIVE
  Randomised controlled trials (RCTs) evaluating the effect of fish oil supplementation on postoperative atrial fibrillation (POAF) following cardiac surgery have produced mixed results. In this study, we examined relationships between levels of red blood cell (RBC) n-3 long-chain polyunsaturated fatty acids (LC-PUFAs) and the incidence of POAF.
  
  
  METHODS
  We used combined data (n=355) from RCTs conducted in Australia and Iceland. The primary end point was defined as POAF lasting >10 min in the first 6 days following surgery. The odds ratios (ORs) for POAF were compared between quintiles of preoperative RBC n-3 LC-PUFA levels by multivariable logistic regression.
  
  
  RESULTS
  Subjects with RBC docosahexaenoic acid (DHA) in the fourth quintile, comprising a RBC DHA range of 7.0-7.9%, had the lowest incidence of POAF. Subjects in the lowest and highest quintiles had significantly higher risk of developing POAF compared with those in the fourth quintile (OR=2.36: 95% CI; 1.07-5.24 and OR=2.45: 95% CI; 1.16-5.17, respectively). There was no association between RBC eicosapentaenoic acid levels and POAF incidence.
  
  
  CONCLUSIONS
  The results suggest a 'U-shaped' relationship between RBC DHA levels and POAF incidence. The possibility of increased risk of POAF at high levels of DHA suggests an upper limit for n-3 LC-PUFAs in certain conditions.
authors.affiliation: 1] Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia [2] Centre for Heart Rhythm Disorders, Discipline of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: R G
authors.initials: RG
authors.lastname: Metcalf
authors.affiliation: 1] Department of Physiology, School of Health Sciences, University of Iceland, Reykjavik, Iceland [2] Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: G V
authors.initials: GV
authors.lastname: Skuladottir
authors.affiliation: Division of Nephrology, Internal Medicine Services, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.
authors.forename: O S
authors.initials: OS
authors.lastname: Indridason
authors.affiliation: Data Management and Analysis Centre, Discipline of Public Health, University of Adelaide, Adelaide, Australia.
authors.forename: T R
authors.initials: TR
authors.lastname: Sullivan
authors.affiliation: 1] Department of Physiology, School of Health Sciences, University of Iceland, Reykjavik, Iceland [2] Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: L
authors.initials: L
authors.lastname: Bjorgvinsdottir
authors.affiliation: 1] Centre for Heart Rhythm Disorders, Discipline of Medicine, University of Adelaide, Adelaide, Australia [2] Cardiovascular Investigation Unit, Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Sanders
authors.affiliation: 1] Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland [2] Division of Cardiology, Internal Medicine Services, Cardiovascular Research Center, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.
authors.forename: D O
authors.initials: DO
authors.lastname: Arnar
authors.affiliation: FOODplus Research Centre, School of Agriculture Food and Wine, University of Adelaide, Adelaide, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Gibson
authors.affiliation: 1] Department of Physiology, School of Health Sciences, University of Iceland, Reykjavik, Iceland [2] Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
authors.forename: R
authors.initials: R
authors.lastname: Heidarsdottir
authors.affiliation: Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: L G
authors.initials: LG
authors.lastname: Cleland
authors.affiliation: 1] Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland [2] Division of Nephrology, Internal Medicine Services, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.
authors.forename: R
authors.initials: R
authors.lastname: Palsson
authors.affiliation: Centre for Heart Rhythm Disorders, Discipline of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: A L
authors.initials: AL
authors.lastname: Farquharson
authors.affiliation: 1] Centre for Heart Rhythm Disorders, Discipline of Medicine, University of Adelaide, Adelaide, Australia [2] Cardiovascular Investigation Unit, Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: G D
authors.initials: GD
authors.lastname: Young
authors.affiliation: 1] Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia [2] Centre for Heart Rhythm Disorders, Discipline of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: M J
authors.initials: MJ
authors.lastname: James
mesh_terms: D000293:Adolescent; D000328:Adult; D001281:Atrial Fibrillation / Q000097:blood* / Q000453:epidemiology*; D001315:Australia / Q000453:epidemiology; D006348:Cardiac Surgical Procedures; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood*; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D015994:Incidence; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D011182:Postoperative Care; D016032:Randomized Controlled Trials as Topic; D055815:Young Adult
chemical_list: D005395:Fish Oils; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid