title: Do omega-6 and trans fatty acids play a role in complex regional pain syndrome? A pilot study.
abstract: OBJECTIVE
  The study aims to compare the omega-6 (n-6) and omega-3 (n-3) highly unsaturated fatty acids (HUFA), and trans fatty acid (trans FA) status of Complex Regional Pain Syndrome (CRPS) patients to pain-free controls.
  
  
  METHODS
  Case control study. Setting. The setting was at a multidisciplinary rehabilitation center.
  
  
  METHODS
  Twenty patients that met the Budapest research diagnostic criteria for CRPS and 15 pain-free control subjects were included in this study. Outcome Measures. Fasting plasma fatty acids were collected from all participants. In CRPS patients, pain was assessed using the McGill Pain Questionnaire-Short Form. In addition, results from the perceived disability (Pain Disability Index), pain-related anxiety (Pain Anxiety Symptom Scale Short Form), depression (Center for Epidemiologic Studies Depression Scale Short Form), and quality of life (Short Form-36 [SF-36]) were evaluated.
  
  
  RESULTS
  Compared with controls, CRPS patients demonstrated elevated concentrations of n-6 HUFA and trans FA. No differences in n-3 HUFA concentrations were observed. Plasma concentrations of the n-6 HUFA docosatetraenoic acid were inversely correlated with the "vitality" section of the SF-36. Trans FA concentrations positively correlated with pain-related disability and anxiety.
  
  
  CONCLUSIONS
  These pilot data suggest that elevated n-6 HUFA and trans FA may play a role in CRPS pathogenesis. These findings should be replicated, and more research is needed to explore the clinical significance of low n-6 and trans FA diets with or without concurrent n-3 HUFA supplementation, for the management of CRPS.
authors.affiliation: Rehabilitation Institute of Chicago, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. chris.ramsden@nih.gov
authors.forename: Christopher
authors.initials: C
authors.lastname: Ramsden
authors.forename: Christine
authors.initials: C
authors.lastname: Gagnon
authors.forename: Joseph
authors.initials: J
authors.lastname: Graciosa
authors.forename: Keturah
authors.initials: K
authors.lastname: Faurot
authors.forename: Robert
authors.initials: R
authors.lastname: David
authors.forename: J Alexander
authors.initials: JA
authors.lastname: Bralley
authors.forename: R Norman
authors.initials: RN
authors.lastname: Harden
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D020918:Complex Regional Pain Syndromes / Q000097:blood* / Q000503:physiopathology; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D043371:Fatty Acids, Omega-6 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010865:Pilot Projects; D011788:Quality of Life; D011795:Surveys and Questionnaires; D044242:Trans Fatty Acids / Q000097:blood*
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D044242:Trans Fatty Acids