title: No association of tobacco use and disease activity in multiple sclerosis.
abstract: OBJECTIVE
  To study whether tobacco use is associated with MRI and clinical disease activity in patients with multiple sclerosis (MS).
  
  
  METHODS
  Prospective cohort study of 87 patients with relapsing-remitting MS originally included in a randomized placebo-controlled trial of omega-3 fatty acids in MS (the OFAMS Study). Serum levels of cotinine (biomarker of tobacco use) were analyzed at baseline and every 6 months for 2 years. MRI activity was assessed at baseline and monthly for 9 months and after 12 and 24 months.
  
  
  RESULTS
  Fifty-three patients (61%) had serum cotinine levels ≥85 nmol/L on ≥60% of the measurements and were considered tobacco users and 34 (39%) had cotinine levels <85 nmol/L, consistent with non-tobacco use. There was no association between tobacco use and the occurrence of new gadolinium-enhancing T1 lesions, new or enlarging T2 lesions, or their aggregate (combined unique activity). Furthermore, there was no association between cotinine levels and MRI activity for the tobacco users, and tobacco users did not have more relapses or Expanded Disability Status Scale progression.
  
  
  CONCLUSIONS
  Our results indicate that tobacco use does not directly influence MRI activity or relapse rate in MS. This may implicate that the reported association between smoking and MS disease progression could be mediated through other mechanisms.
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Silje
authors.initials: S
authors.lastname: Kvistad
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Kjell-Morten
authors.initials: KM
authors.lastname: Myhr
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Trygve
authors.initials: T
authors.lastname: Holmøy
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Jūratė Šaltytė
authors.initials: JŠ
authors.lastname: Benth
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Kristin I
authors.initials: KI
authors.lastname: Løken-Amsrud
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Stig
authors.initials: S
authors.lastname: Wergeland
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Antonie G
authors.initials: AG
authors.lastname: Beiske
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Kristian S
authors.initials: KS
authors.lastname: Bjerve
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Harald
authors.initials: H
authors.lastname: Hovdal
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Finn
authors.initials: F
authors.lastname: Lilleås
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Rune
authors.initials: R
authors.lastname: Midgard
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Tom
authors.initials: T
authors.lastname: Pedersen
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Søren J
authors.initials: SJ
authors.lastname: Bakke
authors.affiliation: Department of Immunology and Transfusion Medicine (S.K.), Norwegian Multiple Sclerosis Competence Centre, Department of Neurology (S.K., S.W., Ø.T.), and Norwegian Multiple Sclerosis Registry and Biobank, Department of Neurology (K.-M.M., S.W., Ø.T.), Haukeland University Hospital, Bergen; KG Jebsen MS Research Centre (S.K., K.-M.M., Ø.T.), Department of Clinical Medicine, University of Bergen; Department of Neurology (T.H.), and HØKH, Research Centre (J.Š.B.), Akershus University Hospital, Lørenskog; Institute of Clinical Medicine (T.H., J.Š.B.), University of Oslo; Department of Neurology (K.I.L.-A.), Innlandet Hospital Trust, Lillehammer; Multiple Sclerosis Centre Hakadal (A.G.B.); Clinic of Laboratory Medicine (K.S.B.) and Department of Neurology (H.H.), St. Olavs Hospital, Trondheim University Hospital; Department of Laboratory Medicine (K.S.B.), Children's and Women's Health, Norwegian University of Science and Technology, Trondheim; Curato Oslo (F.L.); Department of Neurology (R.M.), Molde Hospital; Unit for Applied Clinical Research (R.M.), Norwegian University of Science and Technology, Trondheim; Unilabs Drammen (T.P.), Drammen; and Department of Neuroradiology (S.J.B.), Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Øivind
authors.initials: Ø
authors.lastname: Torkildsen