title: Shortened telomere length in patients with depression: A meta-analytic study.
abstract: BACKGROUND
  Accelerated telomere shortening is associated with stress-related cell damage and aging. Patients with depression have been shown to have shortened life expectancy and to be associated with multiple age-related systemic diseases. Previous studies have examined leukocyte telomere length (LTL) in patients with depression, but have shown inconsistent results.
  
  
  METHODS
  We conducted meta-analyses by pooling relevant results strictly from all eligible case-control studies for cross-sectional comparison of LTL between depressive patients and control subjects (16 studies involving 7207 subjects). The effect sizes (shown as Hedges' g) of each individual study were synthesized by using a random effects model.
  
  
  RESULTS
  Our analysis revealed telomere length is significantly shorter in subjects with depression in comparison to healthy controls (Hedges' g = -0.42, p = 1 × 10(-5), corresponding to r = -0.21). Significant heterogeneity among studies examining LTL in subjects with depression was found (Q = 116.07, df = 16, I(2) = 86.21%, p < 1 × 10(-8)), which can possibly be explained by methods used in measuring telomere length (Q = 18.42, df = 2, p = 1 × 10(-4)). There was no significant publication bias, nor moderating effect of age, female percentage, or illness duration of depression on synthesized results.
  
  
  CONCLUSIONS
  Our results support the hypothesis that depression is associated with accelerated cell aging. Future studies are required to clarify whether the association is mediated through environmental stress, and whether effective treatment can halt cell aging.
authors.affiliation: Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan. Electronic address: paoyenilin@gmail.com.
authors.forename: Pao-Yen
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan. Electronic address: ychuang01@gmail.com.
authors.forename: Yu-Chi
authors.initials: YC
authors.lastname: Huang
authors.affiliation: Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan. Electronic address: chifa.hung@gmail.com.
authors.forename: Chi-Fa
authors.initials: CF
authors.lastname: Hung
mesh_terms: D000375:Aging / Q000235:genetics*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003863:Depression / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D039781:PubMed / Q000706:statistics & numerical data; D012737:Sex Factors; D016615:Telomere; D059506:Telomere Shortening / Q000235:genetics*
keywords: Depression; Meta-analysis; Stress; Telomere