Telomeres, Correlation and Causation
From Ouroboros: "Is telomere length important to the mechanism of aging, in addition to being a marker of advanced chronological age? The jury is still out on that, likely frustrated by the circumstantial nature of the evidence. We know that telomere length appears to be inversely proportional to life expectancy, but of course correlation [does not imply] causation, and lifespan and telomere length could be unrelated signifiers of the same underlying phenomenon. To complicate the issue, we are reminded in a recent review that all telomere ends are not equal ... bulk telomere length might be less important than the lengths of particular telomeres, a forest hiding the most significant trees. More to the point, the telomere lengths of the various chromosomes might be regulated independently, making bulk telomere length something of a red herring." A number of different research groups and young companies are presently working on therapies based upon altering telomere length; expect to see new knowledge and clarity in the field over the next five years.
Link: http://ouroboros.wordpress.com/2007/09/28/telomeres-and-aging-justifying-what-the-ends-mean/