Background: Cigarette smoking is a modifiable risk factor that influences the disease course of patients with multiple sclerosis (MS). However, in patients with a clinically isolated syndrome (CIS), there are conflicting results about the association between smoking and the risk of a subsequent MS diagnosis. The aim of this study was to determine the risk of clinically definite MS (CDMS) in smoking and non-smoking patients at time of a first demyelinating event. Methods: Two hundred and fifty patients, aged 18–50 years, were included in our prospective CIS cohort. At time of the first neurological symptoms, patients completed a questionnaire about smoking habits. Cox regression analyses were performed to calculate univariate and multivariate hazard ratios for CDMS diagnosis in smoking and non-smoking CIS patients. Results: One hundred and fourteen (46%) CIS patients were diagnosed with CDMS during a mean follow-up of 58 months. In total, 79 (32%) patients smoked at time of CIS. Sixty-seven % of the smoking CIS patients were diagnosed with CDMS during follow-up compared to 36% of the non-smoking CIS patients (p < 0.001). Smoking at time of CIS was an independent predictor for CDMS diagnosis (HR 2.3; p = 0.002). Non-smoking CIS patients who had a history of smoking did not have a higher risk for CDMS than those who had never smoked. Conclusions: Smoking at time of CIS was an independent risk factor for a future CDMS diagnosis. This is an additional argument to quit smoking at time of the first attack of suspected MS.

Additional Metadata
Keywords Clinically isolated syndrome, Multiple sclerosis, Smoking
Persistent URL dx.doi.org/10.1007/s00415-018-8780-4, hdl.handle.net/1765/104772
Journal Journal of Neurology: official journal of the European Neurological Society
Citation
van der Vuurst de Vries, R.M, Mescheriakova, J.Y, Runia, T.F, Siepman, T.A.M, Wokke, B.H.A. (Beatrijs H. A.), Samijn, J, & Hintzen, R.Q. (2018). Smoking at time of CIS increases the risk of clinically definite multiple sclerosis. Journal of Neurology: official journal of the European Neurological Society, 1–6. doi:10.1007/s00415-018-8780-4