Smoking affects the interferon beta treatment response in multiple sclerosis.

Area of Science:

• Neuroimmunology
• Epidemiology

Background:

• Multiple Sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system.
• Interferon beta (IFN-β) is a common treatment for relapsing-remitting MS (RRMS).
• Smoking is a known risk factor for MS development and progression.

Purpose of the Study:

• To determine if smoking is associated with increased relapse rates in RRMS patients undergoing IFN-β treatment.
• To investigate potential interactions between smoking and specific genetic markers (HLA-DRB1*15:01, HLA-A*02:01, NAT1 rs7388368A) in this patient group.

Main Methods:

• An observational cohort study utilizing data from the Danish Multiple Sclerosis Biobank.
• Genotyping of 834 RRMS patients treated with IFN-β.
• Analysis of relapse data and smoking status obtained from patient records and questionnaires.

Main Results:

• Smokers with RRMS treated with IFN-β exhibited a significantly higher relapse rate compared to nonsmokers (IRR 1.20, p=0.027).
• Relapse rate increased by 27% per pack of cigarettes smoked daily (IRR 1.27, p=0.012).
• No significant association or interaction was found between smoking and the investigated HLA or NAT1 genetic variants.

Conclusions:

• Smoking is linked to increased relapse activity in RRMS patients receiving IFN-β therapy.
• Genetic factors (HLA, NAT1) do not appear to modify the effect of smoking on relapse rates in this cohort.