Is bipolar disorder associated with accelerating aging? A meta-analysis of telomere length studies

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. (C) 2015 Elsevier B.V. All rights reserved.