Telomeres and human aging: facts and fibs.

Can telomere dynamics, defined by telomere length and attrition rate, provide information about the biology of human aging above and beyond that provided by chronological age? Accruing data suggest that it can. White blood cells (WBCs) have been used as the primary model in attempts to decipher links between aging, aging-related disorders, and telomere dynamics in humans. The WBC model may be appropriate in clinical settings, provided that we fully appreciate its drawbacks and limitations. On the basis of WBC telomere data, it is evident that age-adjusted telomere length is highly variable, highly heritable, longer in women than men, and shorter in people who harbor a host of age-related disorders, whose common denominators may prove to be increased oxidative stress and inflammation. It appears that shorter age-adjusted WBC telomere length augurs a greater risk of morbidity and premature mortality in the elderly. However, it is unsettled whether human telomere dynamics is only a proxy for fundamental mechanisms that govern the course of aging or a key determinant in its progression.