Figure 2.

PRISMA flow diagram of the study selection process. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA statement) [44], we considered the four steps identification, screening, eligibility and inclusion to identify studies for our systematic review. The boxes that are connected through arrows show the steps of the selection process and the number of articles that were included or excluded. A total of 51 articles were found in the literature databases and evaluated for eligibility. The study selection finally revealed 7 studies on telomere length (TL) in patients with multiple sclerosis (MS). A subset of 4 studies was included in the meta-analysis.