Venn diagram showing up-regulated and down-regulated miRNAs in the exploratory screening and the validation study.

In the exploratory screening, there were in total 37 circulating miRNAs exhibiting age-related expression (p<0.05). Of those, only the top-15 miRNAs with the lowest p-values (shown in grey boxes) were further investigated in the validation study. Seven age-related miRNAs were confirmed in the validation study (p<0.05), of which 5 (all showing decreased expression) remained significant after correction for multiple testing; these are indicated in bold. Obviously, the right-hand zone (i.e. miRNAs showing altered expression in the validation study but not the exploratory screening) cannot contain any miRNAs, since the validation study only included those miRNAs that emerged from the exploratory study as the most significantly age-related ones.