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Smoking does not influence disability accumulation in primary progressive multiple sclerosis
Author(s) -
Javizian O.,
Metz L. M.,
Deighton S.,
Koch M. W.
Publication year - 2017
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/ene.13262
Subject(s) - medicine , multiple sclerosis , expanded disability status scale , proportional hazards model , hazard ratio , cohort , risk factor , disease , cohort study , physical therapy , immunology , confidence interval
Background and purpose The modifiable risk factor cigarette smoking has been associated with an increased risk of developing multiple sclerosis ( MS ) and with disease activity in relapsing−remitting MS . However, less is known about the effect of smoking on disease progression in progressive MS . Here the association between cigarette smoking and disability accumulation in primary progressive MS ( PPMS ) is investigated. Methods Kaplan–Meier survival analyses and Cox proportional hazard modelling were used to investigate the influence of cigarette smoking on the risk of reaching Expanded Disability Status Scale ( EDSS ) 4 and 6 as well as the time from EDSS 4 to 6 in patients with PPMS . Results In all, 416 patients with PPMS and available smoking history were identified. Median time to EDSS 4 was 4 years in ever‐smokers and 5 years in never‐smokers ( P = 0.27), and it was 9 years to EDSS 6 in both ever‐smokers and never‐smokers ( P = 0.48). Smokers were not at increased risk of faster progression to EDSS 4, 6 and from EDSS 4 to 6. Age at disease onset was the strongest risk factor for progression to EDSS 4, 6 and from EDSS 4 to 6. Conclusions Our investigation of a large and well‐characterized population based PPMS cohort suggests that cigarette smoking does not influence disability accumulation in PPMS . Our findings support the idea that PPMS is driven by different underlying pathomechanisms than relapsing−remitting MS .