Tobacco smoking and disability progression in multiple sclerosis: United Kingdom cohort study.

Tobacco smoking has been linked to an increased risk of multiple sclerosis. However, to date, results from the few studies on the impact of smoking on the progression of disability are conflicting. The aim of this study was to investigate the effects of smoking on disability progression and disease severity in a cohort of patients with clinically definite multiple sclerosis. We analysed data from 895 patients (270 male, 625 female), mean age 49 years with mean disease duration 17 years. Forty-nine per cent of the patients were regular smokers at the time of disease onset or at diagnosis (ever-smokers). Average disease severity as measured by multiple sclerosis severity score was greater in ever-smokers, by 0.68 (95% confidence interval: 0.36-1.01). The risk of reaching Expanded Disability Status Scale score milestones of 4 and 6 in ever-smokers compared to never-smokers was 1.34 (95% confidence interval: 1.12-1.60) and 1.25 (95% confidence interval: 1.02-1.51) respectively. Current smokers showed 1.64 (95% confidence interval: 1.33-2.02) and 1.49 (95% confidence interval: 1.18-1.86) times higher risk of reaching Expanded Disability Status Scale scores 4 and 6 compared with non-smokers. Ex-smokers who stopped smoking either before or after the onset of the disease had a significantly lower risk of reaching Expanded Disability Status Scale scores 4 (hazard ratio: 0.65, confidence interval: 0.50-0.83) and 6 (hazard ratio: 0.69, confidence interval: 0.53-0.90) than current smokers, and there was no significant difference between ex-smokers and non-smokers in terms of time to Expanded Disability Status Scale scores 4 or 6. Our data suggest that regular smoking is associated with more severe disease and faster disability progression. In addition, smoking cessation, whether before or after onset of the disease, is associated with a slower progression of disability.

Association of a deficit of arousal with fatigue in multiple sclerosis: effect of modafinil.

Multiple sclerosis (MS) is a multifocal demyelinating disease of the central nervous system, leading to chronic disability. Fatigue is a common and distressing symptom of MS which is unrelated to its clinical form, stage of development, the degree of disability, or the lesion load on magnetic resonance imaging. Fatigue in MS is associated with excessive daytime sleepiness and autonomic dysfunction. Recently it has been reported that the wakefulness-promoting drug modafinil may relieve fatigue in MS patients and ameliorate the associated cognitive difficulties. However, it is not clear to what extent the anti-fatigue effect of modafinil may be related to its alerting and sympathetic activating effects. We addressed this question by comparing three groups of subjects, MS patients with fatigue, MS patients without fatigue and healthy controls, matched for age and sex, on measures of alertness (self-ratings on the Epworth and Stanford Sleepiness Scales and on a battery of visual analogue scales; critical flicker fusion frequency; Pupillographic Sleepiness Test; choice reaction time) and autonomic function (systolic and diastolic blood pressure, heart rate, pupil diameter), and by examining the effect of a single dose (200 mg) of modafinil on these measures. MS patients with fatigue, compared with healthy controls, had reduced level of alertness on all the tests used; MS patients without fatigue did not differ from healthy controls. MS patients with fatigue had a reduced level of cardiovascular sympathetic activation compared to the other two groups. Modafinil displayed alerting and sympathomimetic effects in all three groups of subjects. As fatigue in MS is associated with reduced levels of alertness and sympathetic activity, modafinil may exert its anti-fatigue effect in MS by correcting these deficiencies. The anti-fatigue effect of modafinil may reflect the activation of the noradrenergic locus coeruleus (LC), since there is evidence that this wakefulness-promoting nucleus is damaged in MS, and that modafinil, probably via the dopaminergic system, can stimulate the LC. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Reduced EDSS progression in multiple sclerosis patients treated with modafinil for three years or more compared to matched untreated subjects.

BACKGROUND: Modafinil is a wakefulness-promoting drug used to treat narcolepsy, obstructive sleep apnoea, and shift-work sleep disorder. Modafinil has also been used for the treatment of fatigue and excessive sleepiness in other neurological disorders including multiple sclerosis, psychiatric disorders, and for cognitive enhancement. Recent preclinical studies suggest a potential neuroprotective effect of modafinil in neurodegenerative diseases. Therefore, we investigated its neuroprotective potential in multiple sclerosis. OBJECTIVE: To retrospectively assess disease progression in a group of MS patients that had received treatment with modafinil, and a matched group that received no treatment with modafinil. METHODS: We assessed the expanded disability status scale (EDSS) score change, over at least three years, in 30 patients with MS treated with modafinil, and in 90 patients who did not receive modafinil. The two groups were matched for initial EDSS, age, sex, type of disease, disease duration, duration of follow-up, and concomitant disease modifying therapies. Statistical analysis was performed using a general linear regression model. RESULTS: In relapsing-remitting (RR) patients treated with modafinil there was no significant EDSS change over the follow-up period. In RR patients not treated with modafinil, the mean EDSS increased significantly (0.94; p=0.0001) over the follow-up period. Independent of modafinil treatment status, our model indicated an additional mean EDSS increase of 1.1 point (p=0.0002) for progressive patients i.e. mean EDSS change was 1.1 point for modafinil treated, and 1.1+0.94=2.04 points for modafinil-untreated patients. CONCLUSION: Our results support the hypothesis that modafinil has neuroprotective potential, and may play a role in the treatment of multiple sclerosis. A prospective study will need to confirm this finding.