title: Is bipolar disorder associated with accelerating aging? A meta-analysis of telomere length studies.
abstract: BACKGROUND
  Bipolar disorder (BD) is associated with a reduced life expectancy compared to the general population mainly due to a high prevalence of comorbid somatic illnesses. A model of accelerated aging has been proposed as a potential explanation to these epidemiological findings. Nevertheless, studies measuring telomere length (TL) in patients with BD compared to healthy controls have provided mixed results.
  
  
  OBJECTIVE
  To compare TL between BD patients and healthy controls, and to search for potential modeP<rators for observed differences.
  
  
  METHODS
  We performed a systematic review and meta-analysis of original studies comparing TL in patients with BD vs. healthy controls published up to February 24th, 2015 in main electronic databases. Heterogeneity was explored through meta-regression and subgroup analysis.
  
  
  RESULTS
  Seven studies met inclusion criteria (N=1115). There was no difference in TL between participants with BD and healthy controls (Hedges's g=-0.012; 95% CI=-0.418 to 0.393, P=0.952). There was no evidence for publication bias. Heterogeneity was high (I(2)=89.65%). In meta-regression analyses, the percentage of females in healthy control samples (P=0.04) and the methodological quality of included studies (P<0.001) emerged as significant moderators, while subgroup analyses suggest that the type of assay employed to measure TL and age- and gender-matching of BD and HC participants may contribute to heterogeneity.
  
  
  CONCLUSIONS
  Telomere length does not differ between participants with BD vs. healthy controls; this finding does not support the view of BD as an illness associated with accelerated cellular aging. However, more studies controlling for potential confounders are necessary.
authors.affiliation: Center for Translational Psychiatry, Department of Psychiatry and Behavioral Sciences, The University of Texas Medical School at Houston, Houston, TX, USA.
authors.forename: Gabriela D
authors.initials: GD
authors.lastname: Colpo
authors.affiliation: Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Laboratório de Biologia Celular e Molecular, Criciúma, SC, Brazil.
authors.forename: Daniella D
authors.initials: DD
authors.lastname: Leffa
authors.affiliation: Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil.
authors.forename: Cristiano A
authors.initials: CA
authors.lastname: Köhler
authors.affiliation: Department of Psychiatry and Behavioral Sciences, The University of Texas Medical School at Houston, UT Center of Excellence on Mood Disorders, Houston, TX, USA; Laboratory of Molecular Psychiatry, Centro de Pesquisas Experimentais, Hospital de Clínicas de Porto Alegre, and Instituto Nacional de Ciencia e Tecnologia for Translational Medicine, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Flávio
authors.initials: F
authors.lastname: Kapczinski
authors.affiliation: Center for Translational Psychiatry, Department of Psychiatry and Behavioral Sciences, The University of Texas Medical School at Houston, Houston, TX, USA; Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Quevedo
authors.affiliation: Translational Psychiatry Research Group and Department of Clinical Medicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil. Electronic address: andrefc7@terra.com.br.
authors.forename: André F
authors.initials: AF
authors.lastname: Carvalho
mesh_terms: D000328:Adult; D000375:Aging / Q000235:genetics*; D001714:Bipolar Disorder / Q000235:genetics*; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016615:Telomere / Q000235:genetics / Q000378:metabolism*; D059505:Telomere Homeostasis
keywords: Accelerated aging; Bipolar disorder; Cellular senescence; Healthy controls; Meta-analysis; Telomere