title: Association of plasma n-6 and n-3 polyunsaturated fatty acids with synovitis in the knee: the MOST study.
abstract: In osteoarthritis (OA) the synovium is often inflamed and inflammatory cytokines contribute to cartilage damage. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have anti-inflammatory effects whereas omega-6 polyunsaturated fatty acids (n-6 PUFAs) have, on balance, proinflammatory effects. The goal of our study was to assess the association of fasting plasma phospholipid n-6 and n-3 PUFAs with synovitis as measured by synovial thickening on contrast enhanced (CE) knee MRI and cartilage damage among subjects in the Multicenter Osteoarthritis Study (MOST). MOST is a cohort study of individuals who have or are at high risk of knee OA. An unselected subset of participants who volunteered obtained CE 1.5T MRI of one knee. Synovitis was scored in six compartments and a summary score was created. This subset also had fasting plasma, analyzed by gas chromatography for phospholipid fatty acid content, and non-CE MRI, read for cartilage morphology according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) method. The association between synovitis and cartilage morphology and plasma PUFAs was assessed using logistic regression after controlling for the effects of age, sex, and BMI. 472 out of 535 subjects with CE MRI had complete data on synovitis, cartilage morphology and plasma phospholipids. Mean age was 60 years, mean BMI 30, and 50% were women. We found an inverse relation between total n-3 PUFAs and the specific n-3, docosahexaenoic acid with patellofemoral cartilage loss, but not tibiofemoral cartilage loss or synovitis. A positive association was observed between the n-6 PUFA, arachidonic acid, and synovitis. In conclusion, systemic levels of n-3 and n-6 PUFAs which are influenced by diet, may be related to selected structural findings in knees with or at risk of OA. Future studies manipulating the systemic levels of these fatty acids may be warranted to determine the effects on structural damage in knee OA.
authors.affiliation: Boston University Clinical Epidemiology Research and Training Unit, Boston, MA, United States. Electronic address: krbaker@bu.edu.
authors.forename: K R
authors.initials: KR
authors.lastname: Baker
authors.affiliation: Tufts Jean Mayer Human Nutrition Research Center, Boston, MA, United States.
authors.forename: N R
authors.initials: NR
authors.lastname: Matthan
authors.affiliation: Tufts Jean Mayer Human Nutrition Research Center, Boston, MA, United States.
authors.forename: A H
authors.initials: AH
authors.lastname: Lichtenstein
authors.affiliation: Boston University Clinical Epidemiology Research and Training Unit, Boston, MA, United States.
authors.forename: J
authors.initials: J
authors.lastname: Niu
authors.affiliation: Department of Radiology, Boston University Medical Center, Boston, MA, United States.
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.affiliation: Department of Radiology, Boston University Medical Center, Boston, MA, United States.
authors.forename: F
authors.initials: F
authors.lastname: Roemer
authors.affiliation: ULeeds, Leeds, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Grainger
authors.affiliation: The Department of Epidemiology and Biostatistics, University California, San Francisco, San Francisco, CA, United States.
authors.forename: M C
authors.initials: MC
authors.lastname: Nevitt
authors.affiliation: Boston University Clinical Epidemiology Research and Training Unit, Boston, MA, United States.
authors.forename: M
authors.initials: M
authors.lastname: Clancy
authors.affiliation: Department of Preventive Medicine, University of Alabama, Birmingham, AL, United States.
authors.forename: C E
authors.initials: CE
authors.lastname: Lewis
authors.affiliation: The Department of Epidemiology, University of Iowa, Iowa City, IA, United States.
authors.forename: J C
authors.initials: JC
authors.lastname: Torner
authors.affiliation: Boston University Clinical Epidemiology Research and Training Unit, Boston, MA, United States.
authors.forename: D T
authors.initials: DT
authors.lastname: Felson
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002358:Cartilage, Articular / Q000473:pathology; D015331:Cohort Studies; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D043371:Fatty Acids, Omega-6 / Q000097:blood*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000150:complications / Q000473:pathology; D013585:Synovitis / Q000097:blood* / Q000209:etiology / Q000473:pathology
chemical_list: D015415:Biomarkers; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6