Via the Doctor's Guide, news of a study on telomere length and dementia: "Despite previous mixed reports, telomere length cannot be used to predict dementia, according to the largest longitudinal study ... The telomere hypothesis of aging is based on the notion that telomere shortening with each cell division, and therefore with age, results in cell senescence ... This thus led to the 'telomere hypothesis of dementia,' that asks whether telomere shortening contributes to the genesis of certain age-related diseases, such as dementia ... [but] telomere lengths in both the dementia and nondementia patients showed no significant decline with age. ... There was no association between telomere length and change in cognitive status." It would be wonderful progress to find a simple association between known mechanism and disease, but this is rare indeed amidst the vast complexities of human biochemistry.