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.
Keywords: Accelerated aging; Bipolar disorder; Cellular senescence; Healthy controls; Meta-analysis; Telomere.
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