The Impact of Life-Time Alcohol and Smoking Load on Multiple Sclerosis Severity

Abstract

Background: Investigation on the association of smoking and alcohol consumption with Multiple Sclerosis (MS) disease severity is less advanced compared with susceptibility to the disease. We aimed to assess the impact of life-time alcohol and smoking load on MS severity. Methods: 351 patients consecutively admitted at the Department of Neurology were asked to fill the Questionnaire of Lifestyle (part of the European Prospective Investigation into Cancer and Nutrition project). An estimation of the cumulative lifetime smoking and alcohol load was calculated as the weighted sum of the mean number of cigarettes smoked or standard alcohol drinks drunk per day at different ages. The measure of exposure was expressed in terms of pack year and drink year. The disease severity was estimated through the Multiple Sclerosis Severity Score (MSSS). Logistic regression analyses were performed using MSSS (first tertile vs. third tertile) as the outcome. Findings: The median MSSS was higher (3.2 vs. 2.3, p=0.002) in ever compared to never smokers, but we did not find difference between ever and never drinkers (2.7 vs. 2.8, p=ns). Ever smokers were almost two times more likely to fall in the upper MSSS tertile than never smokers. Ever drinkers did not show statistically significant association with MS severity. However, we found an interaction between alcohol consumption and smoke: ever smokers/never drinkers had an Odds Ratio (OR) of 6.4 (Confidence Interval (CI) =1.5-27.1) to fall in the upper MSSS tertile compared with never smokers/never drinkers, but the risk was less in smokers with both lower (1.8, CI=0.6-6.0) or higher drink load (2.6, CI=0.9-7.4). Interpretation: In our pilot study of consecutive MS patients we found a positive trend between the lifetime alcohol and smoking load with disease severity. Knowledge of potentially modifying factors is important from a clinical as well as an etiological point of view. Funding Statement: The fund “Maffeo-Fondazione della Comunita del Novarese” (Novara, Italy) has been supported the fellowship of Dr. Andrei Ivashynka during study design, recruitment and examination of patients. The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report. Declaration of Interests: A. Ivashynka, S. D’Alfonso, M. Copetti, P. Naldi, MA Leone report no conflict of interest related to this study. Ethics Approval Statement: The work was approved by the Ethics Committee of the University Hospital Maggiore della Carita, Novara, Italy