Prevalence of familial multiple sclerosis in Iran: A systematic review and meta-analysis.

B ackground: Familial history of multiple sclerosis (MS) has been considered as one of the etiologic factors of MS by several studies. It is valuable to combine the results of these studies. The aim of this study is to estimate the pooled prevalence of familial MS in Iran using meta-analysis. Methods: Using relevant keywords, national and international databanks were searched. Considering the significant heterogeneity between the results, random effect model was utilized to estimate the pooled prevalence of familial MS using Stata software. Results: After screening the selected articles, 15 studies with total sample size of 6248 (from 60 to 1718) were identified eligible for final meta-analysis. Overall prevalence of familial MS in Iran was estimated as of 11.4% [95% confidence interval (CI): 8.7-14.1]. Point prevalence varied between 3.3% and 26.7%. Conclusion: Our study showed that the familial prevalence of MS among Iranian people is relatively high. More studies are warranted to investigate the effect of familial history as a risk factor for MS.