title: Association between shortened telomere length and rheumatoid arthritis : A meta-analysis.
abstract: OBJECTIVE
  This study aimed to evaluate the relationship between telomere length and rheumatoid arthritis (RA).
  
  
  METHODS
  We performed a meta-analysis of studies comparing the telomere length in RA patients and healthy controls, and conducted subgroup analysis based on ethnicity, age-matched status, study quality, sample type, assay method, subject number, and shared epitope (SE) status.
  
  
  RESULTS
  Nine studies from seven articles, with 388 RA patients and 362 controls, were included. Meta-analysis showed that the telomere length was significantly shorter in all individuals of the RA group than in those of the control group (SMD = -0.833, 95 % CI = -1.332 to -0.334, p = 0.001). Stratification by ethnicity showed significantly shortened telomere lengths in both mixed and age-matched Caucasian populations with RA (SMD = -1.415, 95 % CI = -1.709 to -1.120, p < 1.0 × 10-8; SMD = -0.658, 95 % CI = -1.187 to -0.0.128, p = 0.015). The telomere length was significantly shorter in the RA group than in the age-matched control group; however, this was not the case in the RA group that was not age-matched (SMD = -1.070, 95 % CI = -1.489 to -0.650, p = 5.7 × 10-7; SMD = 0.155, 95 % CI = -0.119 to 0.429, p = 0.267). Stratification by SE status revealed a significantly shortened telomere length in the SE-positive group, but not in the SE-negative group (SMD = -1.033, 95 % CI = -1.398 to -0.768, p < 1.0 × 10-8; SMD = -0.967, 95 % CI = -2.382 to 0.449, p = 0.181). In addition, the telomere length was significantly shorter in the SE-positive RA group than in the SE-negative RA group (SMD = -0.415, 95 % CI = -0.699 to -0.131, p = 0.004).
  
  
  CONCLUSIONS
  Our meta-analysis demonstrated that the telomere length was significantly shorter in patients with RA, and was significantly more so in the SE-positive group than in the SE-negative group.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine Korea University Anam Hospital, Korea University College of Medicine, 73, Inchon-ro, Seongbuk-gu, 02841, Seoul, Korea. lyhcgh@korea.ac.kr.
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.affiliation: The Hospital for Rheumatic Diseases, Hanyang University Medical Center, Seoul, Korea.
authors.forename: S-C
authors.initials: SC
authors.lastname: Bae
mesh_terms: D001172:Arthritis, Rheumatoid / Q000235:genetics; D003430:Cross-Sectional Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007963:Leukocytes, Mononuclear; D016615:Telomere; D059506:Telomere Shortening
keywords: Autoimmune diseases; Biological markers; Etiology; HLA antigens; Risk factors