Gender and telomere length: systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of observational cohorts (graded Level 1 by design analogy)
PubMed 24365661 · doi:10.1016/j.exger.2013.12.004
What was done
Authors conducted a systematic review and random-effects meta-analysis of observational studies indexed in EMBASE and MEDLINE through November 2009 (plus investigator datasets) to test if females have longer telomeres than males and if the gap widens with age. Inclusion required non-diseased cohorts of both sexes and a minimum sample size of 100. Subgroup analysis and meta-regression evaluated age groups, cell types, and assay methods.
What was found
Based on 36 cohorts comprising 36,230 participants, females had statistically significantly longer age-adjusted telomeres than males (standardised difference = 0.090, 95% CI 0.015 to 0.166). The difference did not vary significantly by age group (p=1.00) or cell type (p=0.29). However, effect size varied by measurement technique: Southern blot showed a significant difference, whereas real-time PCR and Flow-FISH did not.
Why it matters
This review provides quantitative evidence that females maintain slightly longer telomeres than males, while demonstrating that choice of laboratory measurement method substantially affects whether this difference is detected.
Limits
The literature search was conducted up to November 2009. Primary evidence is entirely observational and cross-sectional across cohorts. The sex difference was not statistically significant when measured by real-time PCR or Flow-FISH, leaving the root cause of methodological divergence unresolved.
Cited by
- supports Women have leukocyte telomeres that are hundreds of base pairs longer than men's, a difference present at birth.