Environmental risk factors of multiple sclerosis in the Middle  East and North Africa region:  A systematic review

Hossein Maroufi; Seyyed Hosein Mortazavi; Mohammad Ali Sahraian; Sharareh Eskandarieh

doi:10.18502/cjn.v20i3.7693

Hossein Maroufi Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Seyyed Hosein Mortazavi Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Ali Sahraian Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Sharareh Eskandarieh Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/cjn.v20i3.7693

Keywords: Multiple Sclerosis; Risk Factors; Environment; Middle East; North Africa

Abstract

Background: The environmental factors play a major role as risk factors of multiple sclerosis (MS). This study aimed at gathering environmental risk factors of MS in the Middle East and North Africa (MENA).

Methods: We used MEDLINE and EMBASE databases by a systematic review method. Out of a total of 123 studies, 16 studies met the eligibility criteria.

Results: Totally, 47 risk factors were assessed as follows: six studies found sunlight exposure as a protective factor with the odds ratio (OR) ranging from 0.06 to 0.57. Six studies evaluated smoking as a risk factor with the OR ranging from 1.69 in all patients to 6.48 in female patients. Four studies supported measles infection as a risk factor with the OR ranging from 1.60 to 3.77, and in 3 studies, stressful events had a significant association with the OR of 1.80, 1.90, and 32.57.

Conclusion: Among 47 assessed risk factors, sunlight exposure, cigarette smoking, measles infection, Epstein-Barr virus (EBV) infection, and stressful events had a significant association with MS.