Per your response that:
"The article also doesn't say much about how the rate of production of telomerases affect the outcome."
Of course telemerase is an enzyme that provides for the telemeres to regenerate. However, the measurements of the telemeres would be net (calculated after the effects) of naturally produced telemerase. Therefore, any naturally produced telemerase would not be a consideration unless for some reason the rate of natural telemerase production increased.
Supplemented telemerase has been shown to reverse aging in mice that were genetically engineered to grow old.
In normal mice, however, supplemented telemerase caused cancer but they didn't have seriously damaged (very short) telemeres to use the telemerase for regeneration. Accordingly, it might be worth the while of people who are close to death from damaged telemeres to take a telemerase supplement if possible in hopes of reversing their age related symptoms.
"Therefore, any naturally produced telemerase would not be a consideration unless for some reason the rate of natural telemerase production increased."
Well, I wasn't referring so much to increases or decreases of production within a given subject, but to the inherent degrees of variance in the rate of production between subjects throughout a population. I couldn't find much on how that variance was even considered. It's rare that people understand statistics well enough to even grasp what it means when given a median or mean figure, so I'm not really sure how the figure they would get is really expressed. "Based on your telomere length, your mean life expectancy is about x years" Or is it "a to b years"?
Everybody is different. I would want to know so that I could set my priorities. Also, there is an enzyme called telomerase that has reversed the aging process in mice. I would certainly be looking to take it as a supplement if my blood test showed a relatively short life expectancy: