Smoking and disease progression in multiple sclerosis.
BACKGROUND
Although cigarette smokers are at increased risk of developing multiple sclerosis (MS), the effect of smoking on the progression of MS remains uncertain.


OBJECTIVE
To establish the relationship between cigarette smoking and progression of MS using clinical and magnetic resonance imaging outcomes


METHODS
Cross-sectional survey and longitudinal follow-up for a mean of 3.29 years, ending January 15, 2008.


METHODS
Partners MS Center (Boston, Massachusetts), a referral center for patients with MS.


METHODS
Study participants included 1465 patients with clinically definite MS (25.1% men), with mean (range) age at baseline of 42.0 (16-75) years and disease duration of 9.4 (0-50.4) years. Seven hundred eighty patients (53.2%) were never-smokers, 428 (29.2%) were ex-smokers, and 257 (17.5%) were current smokers.


METHODS
Smoking groups were compared for baseline clinical and magnetic resonance imaging characteristics as well as progression and sustained progression on the Expanded Disability Status Scale at 2 and 5 years and time to disease conversion to secondary progressive MS. In addition, the rate of on-study change in the brain parenchymal fraction and T2 hyperintense lesion volume were compared.


RESULTS
Current smokers had significantly worse disease at baseline than never-smokers in terms of Expanded Disability Status Scale score (adjusted P < .001), Multiple Sclerosis Severity Score (adjusted P < .001), and brain parenchymal fraction (adjusted P = .004). In addition, current smokers were significantly more likely to have primary progressive MS (adjusted odds ratio, 2.41; 95% confidence interval, 1.09-5.34). At longitudinal analyses, MS in smokers progressed from relapsing-remitting to secondary progressive disease faster than in never-smokers (hazard ratio for current smokers vs never-smokers, 2.50; 95% confidence interval, 1.42-4.41). In addition, in smokers, the T2-weighted lesion volume increased faster (P = .02), and brain parenchymal fraction decreased faster (P = .02).


CONCLUSIONS
Our data suggest that cigarette smoke has an adverse influence on the progression of MS and accelerates conversion from a relapsing-remitting to a progressive course.
Healy
Brian C
BC
Department of Neurology, Partners MS Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Ali
Eman N
EN
Guttmann
Charles R G
CR
Chitnis
Tanuja
T
Glanz
Bonnie I
BI
Buckle
Guy
G
Houtchens
Maria
M
Stazzone
Lynn
L
Moodie
Jennifer
J
Berger
Annika M
AM
Duan
Yang
Y
Bakshi
Rohit
R
Khoury
Samia
S
Weiner
Howard
H
Ascherio
Alberto
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D020520:Brain Infarction / Q000473:pathology; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000401:mortality / Q000473:pathology* / Q000523:psychology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects* / Q000523:psychology*; D018709:Statistics, Nonparametric; D055815:Young Adult