1Sharareh Eskandarieh, 1Seyyed Hosein Mortazavi, 2Amir Almasi-Hashiani, 1Abdorreza Naser Moghadasi, 1Mohammad Ali Sahraian

1Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Epidemiology, School of Health, Arak University of Medical Sciences, Arak, Iran


Multiple sclerosis is a chronic central nervous system disease and primary progressive multiple sclerosis (PPMS) is one the main type of MS which like any other autoimmune disease has undetermined environmental risk factors and can be triggered by smoking, drug substance and alcohol consumption (1).

The aim of the study was to identify possible association of smoking, drug substance and alcohol drinking with PPMS development.

Material(s) and Method(s):

The population-based case–control study was conducted Tehran, Iran from 2019-2020 in. PPMS cases was diagnosed based on the 2017 McDonald criteria by a neurologist in Sina hospital (tertiary care referral center).

The telephone interviews were carried for data collection out by 4 well-trained interviewers, using environmental risk factors in MS questionnaire. The validity and reliability of the Persian version of the questionnaire were approved (2).

The same questionnaire was used for case and control groups.

The standard random digit dialing was used to select control participants from the same source population (3-4). The sex and residency were matched in both groups. Logistic regression analysis was used to estimate adjusted and unadjusted ORs (odds ratio) at 95% confidence intervals (CI) by using SPSS software.


Completely 146 PPMS cases and 294 healthy controls were registered in the study.

The mean age (SD) for cases and controls were 47.0 (9.4) and 37.7 (6.1) years, respectively (P =0.001).

Being passive smoker (OR=2.20 (CI=1.34-3.62)) and having ever smoked cigarette (OR=2.48 (CI=1.44-4.27)) were considered risk factors associated with PPMS development, while having ever smoked water-pipe was not significantly relevant to PPMS risk (OR=1.19 (CI=0.62-2.26)). Those who had all three types of smoking including passive smoking, water-pipe and cigarette smoking (OR=10.45) had 10 times higher risk of PPMS, comparing to those without any type of smoking. There is no significant association between different types of substances abuse and alcohol consumption and PPMS risk, such as Cannabis: OR=1.58 (CI=0.47-5.24), Opioid: OR= 0.90 (CI=0.35-2.29), Stimulants: OR=0.85 (CI=0.14-4.87), Beer: OR=0.61 (CI=0.29-1.26), Wine: OR= 0.73 (CI=0.35-1.53) and Whisky/vodka: OR= 0.71 (CI=0.34-1.49).


The passive smoking and cigarette smoking and are important risk factors for developing PPMS. Using three types of smoking including water-pipe, cigarette and passive smoking may increase risk of PPMS occurrence comparing to subjects without history of smoking (3,4 (. According to regional increase in smoking water-pipe and cigarette in MENA region, this finding indicate the need for necessary health interventions to prevention PPMS risk.