Leukocyte telomere length in patients with schizophrenia and related disorders: a meta-analysis of case-control studies

Context Telomere length may serve as a biomarker of cellular aging. The literature assessing telomere length in schizophrenia contains conflicting results. Objective To assess differences in leukocyte telomere length (LTL) in peripheral blood in patients with schizophrenia and related disorders and healthy controls and to explore the effect of potential confounding variables. Data sources A search of Ovid MEDLINE, and Proquest databases was conducted to identify appropriate studies published from database inception through December 2020. The review protocol was registered with PROSPERO-ID: CRD42021233280. Study selection The initial literature search yielded 192 studies. After study selection in 3 phases, we included 29 samples from 22 studies in the meta-analysis database. Data extraction We used random effects and meta-regression models to derive Cohen d values with pooled 95% confidence intervals (CI) as estimates of effect size (ES) and to test effects of potential moderators. Results The overall meta-analysis included 4145 patients with schizophrenia and related disorders and 4184 healthy controls and showed that LTL was significantly shorter in patients, with a small to medium effect size (ES, −0.388; 95% CI, −0.492 to −0.283; p < 0.001). Subgroup meta-analyses did not find a significant effect of age or illness duration on differences in LTL in patients with psychosis relative to controls. Meta-regression analyses showed that none of the putative moderators had a significant effect on effect size estimates. Conclusions This meta-analysis find further support for the hypothesis of accelerated cellular aging in schizophrenia and related disorders and highlights the need for large longitudinal studies with repeated LTL measurements over time and appropriate assessments of associated factors.