Relative Telomere Length and Mitochondrial DNA Copy Number Variation with Age: Association with Plasma Folate and Vitamin B12.

•Elderly people (≥60 years) have shorter telomeres and lower mtCN than the younger ones (<60 years).•There is a positive correlation between the rTL and mtCN.•Plasma folate and vitamin B12 levels were positively correlated with the rTL and mtCN.•Folate and vitamin B12 status may delay aging by preventing the reduction in length and mtCN.