The prevalence of multiple sclerosis in the Middle East.

BACKGROUND The prevalence of multiple sclerosis (MS) in the Middle East has been reported to be low to medium. METHODS To verify this assertion we conducted a review of published data on the occurrence of MS in the Middle East. RESULTS Fourteen studies reporting on the prevalence of MS in the Middle East were initially identified, 5 of which were excluded due to inadequate data or serious methodological limitations. The data from the 9 included studies suggested that the prevalence of MS may vary widely within the Middle East, from low to high. However, these 9 studies were inconsistent in case ascertainment, inclusion criteria and methods of prevalence calculation, and most did not include age/sex standardization. CONCLUSION Methodological inconsistencies among studies make it difficult to be confident in drawing conclusions about the prevalence of MS in the Middle East. Nevertheless, there is little evidence to support the assertion that the prevalence of MS in the Middle East is low to medium. Rather, the prevalence of MS in the Middle East may range from low to high, depending on the specific population and environment of study. However, to confirm these findings, further epidemiological research is needed.