Fig. 7

Effect of sex on the epigenetic age of brain tissue. Each panel depicts a forest plot resulting from the meta-analysis of sex effects. Each row in a forest plot shows the mean difference in epigenetic age between men and women and a 95 % confidence interval. To combine the coefficient estimates from the respective studies into a single estimate, we applied a fixed-effects model weighted by inverse variance, which is implemented in the metafor R package [89]. a Gender did not have a significant effect on the epigenetic age of the cerebellum, which is known to age more slowly than other brain regions according to the epigenetic clock [43]. b When excluding cerebellar samples from the analysis, we find that male brain regions exhibit a significantly higher age acceleration than female brain regions (mean difference = 0.82, meta-analysis p = 3.1 × 10^–5). The difference remains significant even after adjusting for intra-subject correlations using a linear mixed effects model (mean difference = 0.77, p = 0.0034)