The association of telomere length with substance use disorders: a systematic review and meta‐analysis of observational studies

Abstract

Background and Aims Several recent studies have investigated the relationship between telomere length and substance use disorders with inconsistent results. We aimed to assess this association and to identify moderators of the relationship. Methods Systematic review and meta‐analysis. Selection criteria were observational studies reporting telomere length in people with a substance use disorder compared with a control group. Studies focused solely on nicotine addiction, employing other study designs, and non‐human studies were excluded. Study selection and data extraction were independently conducted by two researchers following a standardized protocol and included studies until December 2019. Standardized mean differences were used as the effect size index [d; 95% confidence interval (CI)] and random‐effects models were used for the meta‐analysis. Cochran's Q‐statistic, I2 index, visual inspection of the forest plot and a 95% prediction interval were applied to verify study heterogeneity. Subgroup analyses and meta‐regressions were conducted to explore heterogeneity. Small study effects were examined using the ‘funnel plot’, the Egger test, Duval & Tweedie's trim‐and‐fill method and the precision‐effect test–precision‐effect estimate with standard error (PET‐PEESE) method. The risk of bias and the quality of evidence were assessed. Results Ten studies (12 analysis units with 2671 cases and 4532 controls) met the selection criteria. An overall effect size of moderate magnitude was found (d+ = −0.63; 95% CI = −1.00 and −0.26; P = 0.0008). A potential small study effect was detected, as well as large heterogeneity between studies (Q‐statistic P < 0.001, I2 = 97.3%). Selection of controls, reporting laboratory quality control procedures and total sample size significantly affected the effect size. The quality of the evidence was very low, based on risk of bias analysis and the grading of recommendations assessment, development and evaluation (GRADE) system. Conclusions People with substance use disorders appear to have shorter telomere length than controls; however, this finding should be interpreted with caution due to the poor quality of the evidence.

Telomere length and mitochondrial DNA copy number in bipolar disorder: identification of a subgroup of young individuals with accelerated cellular aging

“…However, several trends may be noted: (i) although they had the same age, Group 2 seemed to have the highest densities of mood episodes (whatever the polarity being considered) than Group 3; (ii) individuals in Group 3 also tend to be more on lithium than Group 2 who seemed to be more on anticonvulsants which is consistent with the literature where individuals with BD taking lithium appear to have a longer telomere length than others. Some other variables that may be associated with cellular aging, such as suicide attempts [ 40 ] and substance use disorders [ 41 ] (current tobacco or past alcohol misuse for example) have been analysed in this study, but no significant differences were observed between subgroups. If replicated in larger and independent samples, the existence of such a subgroup would deserve further characterization to better identify which young individuals with BD might be more at risk for accelerated cellular aging.…”

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

“…Chronic alcohol consumption is well known to contribute to premature aging. With regard to cellular aging, alcohol abuse was associated with significantly shorter TL in a recent meta-analysis of six studies (SMD = −0.68) [219]. In contrast, consumption of coffee, which is rich in antioxidants, was related to longer telomeres.…”

Significant Shortening of Leukocyte Telomere Length in Korean Patients with Bipolar Disorder 1

“…We could not control them in this study. Fourth, we should consider psychiatric comorbidities such as anxiety and substance use disorder [ 26 , 27 ], as well as medical illnesses [ 28 , 29 ]. Heavy alcohol use itself is associated with telomere shortening [ 30 ], and psychiatric medications can influence telomere length [ 31 , 32 ].…”