title: The Association Between Musculoskeletal Pain and Circulating Ornithine: A Population-Based Study.
abstract: Based on several previous clinical studies, we hypothesized that ornithine levels are different among subjects with persistent musculoskeletal pain compared with other subjects in the population.
  
  
  
  The study sample consisted of 221 adults with nonpersistent pain, 76 with persistent pain, and 61 with no pain. Concentrations of glutamic acid, ornithine, citrulline, arginine, proline, and spermidine were analyzed using a mass spectrometer.
  
  
  
  Lapinlahti municipality in Finland.
  
  
  
  For the subjects with no pain, nonpersistent pain, and persistent pain, the ornithine concentrations for men were 85.3 µmol/L (SD = 28.9 µmol/L), 98.9 µmol/L (SD = 37.8 µmol/L), and 102.1 µmol/L (SD = 37.1 µmol/L; P  = 0.033), respectively. The corresponding concentrations for women were 82.8 µmol/L (SD = 25.2 µmol/L), 83.7 µmol/L (SD = 27.8 µmol/L), and 103.2 µmol/L (SD = 34.9 µmol/L; P  = 0.0031). There were no significant differences between the pain groups for any of the other investigated amino acids. Relative sex-specific ornithine concentration adjusted for age, glomerular filtration rate, smoking, body mass index, physical activity, and depressive symptoms was associated with pain ( P  = 0.025), the ornithine level being higher in the persistent pain group than in the no pain ( P  = 0.006) and nonpersistent pain ( P  = 0.032) groups.
  
  
  
  Ornithine levels are elevated in general population subjects with persistent pain.
authors.affiliation: General Practice, Institute of Public Health and Clinical Nutrition.|Primary Health Care Unit and.
authors.forename: Pekka
authors.initials: P
authors.lastname: Mäntyselkä
authors.affiliation: Psychiatry, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Department of Psychiatry, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Toni
authors.initials: T
authors.lastname: Ali-Sisto
authors.affiliation: Primary Health Care Unit and.|Department of General Practice, Unit of Primary Health Care, and.
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.affiliation: Endocrinology, Abdominal Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Leo
authors.initials: L
authors.lastname: Niskanen
authors.affiliation: Psychiatry, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Department of Psychiatry, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Heimo
authors.initials: H
authors.lastname: Viinamäki
authors.affiliation: Metabolomics Unit, Institute for Molecular Medicine Finland FIMM, Helsinki, Finland.
authors.forename: Vidya
authors.initials: V
authors.lastname: Velagapudi
authors.affiliation: Psychiatry, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Department of Psychiatry, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Soili M
authors.initials: SM
authors.lastname: Lehto
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D009952:Ornithine / Q000097:blood*; D011159:Population Surveillance / Q000379:methods
chemical_list: D015415:Biomarkers; D009952:Ornithine
keywords: Persistent Pain;  Musculoskeletal