Abstract
Background
Cigarette smoking increases the risk for development of multiple sclerosis and modifies the clinical course of the disease. In this study, we determined whether smoking is a risk factor for early conversion to clinically definite multiple sclerosis after a clinically isolated syndrome.
Methods
We included 129 patients with a clinically isolated syndrome, disseminated white-matter lesions on brain magnetic resonance imaging, and positive oligoclonal bands in the cerebrospinal fluid. The patients’ smoking status was obtained at the time of the clinically isolated syndrome.
Results
During a follow-up time of 36 months, 75% of smokers but only 51% of non-smokers developed clinically definite multiple sclerosis, and smokers had a significantly shorter time interval to their first relapse. The hazard ratio for progression to clinically definite multiple sclerosis was 1.8 (95% confidence interval, 1.2–2.8) for smokers compared with non-smokers (P = 0.008).
Conclusions
Smoking is associated with an increased risk for early conversion to clinically definite multiple sclerosis after a clinically isolated syndrome, and our results suggest that smoking is an independent but modifiable risk factor for disease progression of multiple sclerosis. Therefore, it should be considered in the counseling of patients with a clinically isolated syndrome.
| 1 Sospedra M Martin R . Immunology of multiple sclerosis. Annu Rev Immunol 2005; 23: 683–747. Google Scholar | Crossref | Medline | ISI | |
| 2 Ascherio A Munger KL . Environmental risk factors for multiple sclerosis. Part II: Noninfectious factors. Ann Neurol 2007; 61: 504–513. Google Scholar | Crossref | Medline | ISI | |
| 3 Ascherio A Munger KL . Environmental risk factors for multiple sclerosis. Part I: the role of infection. Ann Neurol 2007; 61: 288–299. Google Scholar | Crossref | Medline | ISI | |
| 4 Giovannoni G Ebers G . Multiple sclerosis: the environment and causation. Curr Opin Neurol 2007; 20: 261–268. Google Scholar | Crossref | Medline | ISI | |
| 5 Hernan MA Olek MJ Ascherio A . Cigarette smoking and incidence of multiple sclerosis. Am J Epidemiol 2001; 154: 69–74. Google Scholar | Crossref | Medline | ISI | |
| 6 Pekmezovic T Drulovic J Milenkovic M . Lifestyle factors and multiple sclerosis: a case-control study in Belgrade. Neuroepidemiology 2006; 27: 212–216. Google Scholar | Crossref | Medline | ISI | |
| 7 Riise T Nortvedt MW Ascherio A . Smoking is a risk factor for multiple sclerosis. Neurology 2003; 61: 1122–1124. Google Scholar | Crossref | Medline | ISI | |
| 8 Thorogood M Hannaford PC . The influence of oral contraceptives on the risk of multiple sclerosis. Br J Obstet Gynaecol 1998; 105: 1296–1299. Google Scholar | Crossref | Medline | |
| 9 Villard-Mackintosh L Vessey MP . Oral contraceptives and reproductive factors in multiple sclerosis incidence. Contraception 1993; 47: 161–168. Google Scholar | Crossref | Medline | ISI | |
| 10 Hernan MA Jick SS Logroscino G Olek MJ Ascherio A Jick H . Cigarette smoking and the progression of multiple sclerosis. Brain 2005; 128: 1461–1465. Google Scholar | Crossref | Medline | ISI | |
| 11 O'Riordan JI Thompson AJ Kingsley DP . The prognostic value of brain MRI in clinically isolated syndromes of the CNS. A 10-year follow-up. Brain 1998; 121: 495–503. Google Scholar | Crossref | Medline | ISI | |
| 12 Jacobs LD Beck RW Simon JH . Intramuscular interferon beta-1a therapy initiated during a first demyelinating event in multiple sclerosis. CHAMPS Study Group. N Engl J Med 2000; 343: 898–904. Google Scholar | Crossref | Medline | ISI | |
| 13 Kappos L Polman CH Freedman MS . Treatment with interferon beta-1b delays conversion to clinically definite and McDonald MS in patients with clinically isolated syndromes. Neurology 2006; 67: 1242–1249. Google Scholar | Crossref | Medline | ISI | |
| 14 Berger T Rubner P Schautzer F . Antimyelin antibodies as a predictor of clinically definite multiple sclerosis after a first demyelinating event. N Engl J Med 2003; 349: 139–145. Google Scholar | Crossref | Medline | ISI | |
| 15 Fazekas F Offenbacher H Fuchs S . Criteria for an increased specificity of MRI interpretation in elderly subjects with suspected multiple sclerosis. Neurology 1988; 38: 1822–1825. Google Scholar | Crossref | Medline | ISI | |
| 16 McDonald WI Compston A Edan G . Recommended diagnostic criteria for multiple sclerosis: guidelines from the International Panel on the diagnosis of multiple sclerosis. Ann Neurol 2001; 50: 121–127. Google Scholar | Crossref | Medline | ISI | |
| 17 Poser CM Paty DW Scheinberg L . New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Ann Neurol 1983; 13: 227–231. Google Scholar | Crossref | Medline | ISI | |
| 18 Groman E Bayer P Kunze U Schmeiser-Rieder A Schoberberger R . Analysis of the needs for diagnosis and therapy of tobacco dependence in Austria. Wien Med Wochenschr 2000; 150: 109–114. Google Scholar | Medline | |
| 19 Munger KL Zhang SM O'Reilly E . Vitamin D intake and incidence of multiple sclerosis. Neurology 2004; 62: 60–65. Google Scholar | Crossref | Medline | ISI | |
| 20 Koch M van Harten A Uyttenboogaart M De Keyser J . Cigarette smoking and progression in multiple sclerosis. Neurology 2007; 69: 1515–1520. Google Scholar | Crossref | Medline | ISI | |
| 21 Stedman RL . The chemical composition of tobacco and tobacco smoke. Chem Rev 1968; 68: 153–207. Google Scholar | Crossref | Medline | ISI | |
| 22 Wilson J . Cyanide in human disease: a review of clinical and laboratory evidence. Fundam Appl Toxicol 1983; 3: 397–399. Google Scholar | Crossref | Medline | |
| 23 Lundquist P Rosling H Sorbo B Tibbling L . Cyanide concentrations in blood after cigarette smoking, as determined by a sensitive fluorimetric method. Clin Chem 1987; 33: 1228–1230. Google Scholar | Crossref | Medline | ISI | |
| 24 Hernandez Avila M Liang MH Willett WC . Reproductive factors, smoking, and the risk for rheumatoid arthritis. Epidemiology 1990; 1: 285–291. Google Scholar | Crossref | Medline | |
| 25 Costenbader KH Kim DJ Peerzada J . Cigarette smoking and the risk of systemic lupus erythematosus: a meta-analysis. Arthritis Rheum 2004; 50: 849–857. Google Scholar | Crossref | Medline | |
| 26 George J Levy Y Shoenfeld Y . Smoking and immunity: an additional player in the mosaic of autoimmunity. Scand J Immunol 1997; 45: 1–6. Google Scholar | Crossref | Medline | ISI | |
| 27 Manfredsdottir VF Vikingsdottir T Jonsson T . The effects of tobacco smoking and rheumatoid factor seropositivity on disease activity and joint damage in early rheumatoid arthritis. Rheumatology (Oxford) 2006; 45: 734–740. Google Scholar | Crossref | Medline | ISI | |
| 28 Sopori ML Kozak W . Immunomodulatory effects of cigarette smoke. J Neuroimmunol 1998; 83: 148–156. Google Scholar | Crossref | Medline | ISI |

