[The effect of tobacco smoking on clinical effectiveness of immunomodulatory treatment in multiple sclerosis patients].

Environmental causes and genetic factors play important role in causation of multiple sclerosis (MS). Tobacco smoking is recognized as a risk factor of the most common inflammatory demyelinating disorder of central nervous system. Experimental studies showed inhibitory effect of tobacco smoke compounds on interferon production. The aim of this study was the evaluation of tobacco smoking on clinical effectiveness of immunomodulatory treatment of multiple sclerosis. Material and methods. The study included 79 multiple sclerosis patients treated with interferon beta for at least two years. MS was diagnosed basing on Mc Donald criteria. The study group included patients participating in reimbursed immunomodulatory treatment of MS. Disease duration, clinimetric evaluation based on EDSS, relapses rate before and during disease modifying therapy (DMT) were analyzed. Results. Current smokers constituted 19% of MS patients undergoing DMT with interferon beta. No differences in disease duration (3, 2 - 4 and 3, 2 - 4 years; median, interquartile range), EDSS score (1; 0,0 - 1,5 and 1; 0,0 -1,75) and relapse rate before DMT initiation (3; 2,0 - 3,5 and 3, 2,0- 4,0) respectively between smokers and non-smokers were found. Interferon beta treatment caused reduction in relapse rate both in non-smokers (before treatment: 2; 2-3, during DMT: 0; 0-0, median; interquartile range, P<0.0001), and smokers (before treatment : 2; 2-4, during DMT: 0; 0 - 0, P = 0.0001). In non-smoking MS patients the relapse rate during MDT correlated with disease duration (Kendall tau = 0.220; P=0.0270), but such a relationship was not observed in smokers with MS. In multiple regression analysis, in the model including the effect of disease duration, baseline EDSS score and smoking status on relapse rate during DMT tobacco smoking was found as the significant (p=0.0012) and independent factor (B = 0.4597).