We know it only takes one critically short telomere to make a cell die, so it's clear that the more really short telomeres a person has the faster problems will develop.
Quotes about telomeres (4 Quotes)
If you were to search for the genetic mutation behind this mouse's disease, you wouldn't find it there isn't one. These mice develop disease only because their telomeres are short, and having telomerase doesn't lengthen them right away.
Normal levels of telomerase didn't lengthen short telomeres in our mice, so the longer the telomeres are to start with, the longer transplanted stem cells will be able to divide and the more likely the transplant is to succeed.
Most of the tissues that age ... that we're interested in -- the brain, the heart, the muscle, the kidney, etc. -- those cells never divide at all and they never replicate their nuclear DNA so their telomeres can't get shorter and, therefore, that couldn't affect their longevity,