Leukocyte telomere length and hippocampus volume: a meta-analysis [version 1; referees: 2 approved]

Leukocyte telomere length has been shown to correlate to hippocampus volume, but effect estimates differ in magnitude and are not uniformly positive. This study aimed primarily to investigate the relationship between leukocyte telomere length and hippocampus gray matter volume by meta-analysis and secondarily to investigate possible effect moderators. Five studies were included with a total of 2107 participants, of which 1960 were contributed by one single influential study. A random-effects meta-analysis estimated the effect to = 0.12 [95% CI -0.13, 0.37] in the presence of r heterogeneity and a subjectively estimated moderate to high risk of bias. There was no evidence that apolipoprotein E (APOE) genotype was an effect moderator, nor that the ratio of leukocyte telomerase activity to telomere length was a better predictor than leukocyte telomere length for hippocampus volume. This meta-analysis, while not proving a positive relationship, also is not able to disprove the earlier finding of a positive correlation in the one large study included in analyses. We propose that a relationship between leukocyte telomere length and hippocamus volume may be mediated by transmigrating monocytes which differentiate into microglia in the brain parenchyma. Gustav Nilsonne ( ) Corresponding author: [email protected] Nilsonne G, Tamm S, Månsson KNT How to cite this article: et al. Leukocyte telomere length and hippocampus volume: a meta-analysis 2015, :1073 (doi: ) [version 1; referees: 2 approved] F1000Research 4 10.12688/f1000research.7198.1 © 2015 Nilsonne G . This is an open access article distributed under the terms of the , Copyright: et al Creative Commons Attribution Licence which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The authors declare that no grants were involved in supporting this work. Grant information: Competing interests: The authors declare that they have no competing interests. 15 Oct 2015, :1073 (doi: ) First published: 4 10.12688/f1000research.7198.1 1,2 1,2 3,4