Methylenetetrahydrofolate Reductase 677OT and Methionine Synthase 2756A>G Mutations: No Impact on Survival, Cognitive Functioning,or Cognitive Decline in Nonagenarians

摘要

COGNITIVE functioning is central in successful aging and longevity. Cognition has been shown to be associated with mortality in several studies among younger elderly persons (1). Although many factors such as marital status, smoking status, and education (with proven influence on mortality among younger elderly persons) apparently lose their importance in the oldest-old, cognitive functioning and other measures of current resources are still strong predictors of mortality among the oldest-old (2). Several reports have shown an association between homocysteine (a sulfur-containing amino acid), cognitive functioning, and survival among the oldest-old (3-5). Plasma total homocysteine has been associated with cardiovascular events and cardiovascular mortality in men (6) and women (7,8), including a strong association with all-cause mortality in elderly persons (5,9,10). The mechanism for the effect of homocysteine on cognitive decline and whether homocysteine itself is the toxic compound is largely unknown. However, it is quite clear that high homocysteine concentrations predicts cognitive decline (11-13).