title: Dietary Intake of Polyunsaturated Fatty Acids and Pain in Spite of Inflammatory Control Among Methotrexate-Treated Early Rheumatoid Arthritis Patients.
abstract: To investigate potential associations between dietary intake of polyunsaturated fatty acids (FAs) and pain patterns in early rheumatoid arthritis (RA) patients after 3 months of methotrexate (MTX) treatment.
  
  
  
  We included 591 early RA patients with MTX monotherapy from a population-based prospective case-control study, the Epidemiological Investigation of Rheumatoid Arthritis. Dietary data on polyunsaturated FAs (food frequency questionnaires) were linked with data on unacceptable pain (visual analog scale [VAS] >40 mm), noninflammatory/refractory pain (VAS >40 mm and C-reactive protein [CRP] level <10 mg/liter), and inflammatory pain (VAS >40 mm and CRP level >10 mg/liter) after 3 months. Statistical analysis included logistic regression.
  
  
  
  After 3 months of MTX treatment, 125 patients (21.2%) had unacceptable pain, of which 92 patients had refractory pain, and 33 patients had inflammatory pain. Omega-3 FA intake was inversely associated with unacceptable pain and refractory pain (odds ratio [OR] 0.57 [95% confidence interval (95% CI) 0.35-0.95] and OR 0.47 [95% CI 0.26-0.84], respectively). The omega-6:omega-3 FA ratio, but not omega-6 FA alone, was directly associated with unacceptable pain and refractory pain (OR 1.70 [95% CI 1.03-2.82] and OR 2.33 [95% CI 1.28-4.24], respectively). Furthermore, polyunsaturated FAs were not associated with either inflammatory pain or CRP level and erythrocyte sedimentation rate at followup. Omega-3 FA supplementation was not associated with any pain patterns.
  
  
  
  Omega-3 FA was inversely associated with, and the omega-6:omega-3 FA ratio was directly associated with, unacceptable and refractory pain, but not with inflammatory pain or systemic inflammation. The inverse association between omega-3 FA and refractory pain may have a role in pain suppression in RA.
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lourdudoss
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Daniela
authors.initials: D
authors.lastname: Di Giuseppe
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Helga
authors.initials: H
authors.lastname: Westerlind
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Klareskog
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ronald F
authors.initials: RF
authors.lastname: van Vollenhoven
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jon
authors.initials: J
authors.lastname: Lampa
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D018771:Arthralgia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D004032:Diet / Q000009:adverse effects; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000009:adverse effects; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D008297:Male; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D010147:Pain Measurement; D010148:Intractable Pain / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D011446:Prospective Studies; D065840:Protective Factors; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D018836:Inflammation Mediators; D002097:C-Reactive Protein; D008727:Methotrexate