Tehran University of Medical Sciences Current Journal of Neurology 2717-011X 16 1 2017 01 04 34 40 EN Mohammad Ali Sahraian Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran Mohammad Sahebkar Department of Statistics and Epidemiology, School of Health, Sabzevar University of Medical Sciences, Sabzevar, Iran Rouhollah Dehghani Social Determinants of Health Research Center, Department of Environment Health, School of Health, Kashan University of Medical Sciences, Kashan, Iran Milad Derakhshan-Jazari Department of Occupational Health, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Vahid Kazami-Moghaddam Department of Environmental Health, School of Health, Neyshabur University of Medical Sciences, Neyshabur, Iran Ebrahim Kouchaki Department of Neurology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran 2016 01 02 2016 11 18 There has been a global rising trend in recent years in the incidence of multiple sclerosis (MS). Despite being an MS low-risk region, this disease has also been recently on the rise in the Middle East. As part of the Middle East, Iran has not been spared either; however, the cause of this dramatic increase remains to be discovered. This study reviews possible reasons for this increase in Iran. Although many factors such as the increased rate of smoking, lifestyle changes, modernization, and contact with toxic solvents can be proposed as reasons for this sudden rise in the prevalence of MS in Iran, these factors cannot be taken as definite causes and further studies are required to prove their impact. https://ijnl.tums.ac.ir/index.php/ijnl/article/view/950 https://ijnl.tums.ac.ir/index.php/ijnl/article/download/950/311