Centenarians appear to be physically younger than many of their younger counterparts amongst the old. "Physically younger" is a term up for much discussion and definition, of course, but I'm thinking of specific measures of cellular and biochemical damage, or the functioning of important organs and systems in the body when I say this. Centenarians are, on average, less damaged - which is why they are, on average, still around long after their peers have aged to death.

This is particularly apparent in the aging of the immune system:

In the present NONA immune longitudinal study, we investigate the previously identified Immune Risk Profile (IRP), defined by an inverted CD4/CD8 ratio and associated with persistent cytomegalovirus infection and increased numbers of CD8+CD28- cells, relative 6-year survival and age in NONA individuals. These subjects have now reached age 92, 96, and for the first time in this study, 100 years at follow-up. A 55 year old middle-aged group was used for comparison

...

The results confirmed the importance of the IRP as a major predictor of mortality in this population of very old. Moreover, the results suggested that survival to the age of 100 years is associated with selection of individuals with an "inverted" IRP that was stable across time, i.e., maintenance of a high CD4/CD8 ratio and low numbers of CD8+CD28- cells. The results underlines the importance of a longitudinal study design in dissecting immune parameters predictive of survival and show for the first time that centenarian status is associated with avoidance of the IRP over at least the previous 6 years and probably throughout life.

A damaged immune system leads into a spiral of further damage to your biochemistry and bodily systems. Those people with continually effective immune systems stand a greater chance of living longer, healthier lives. The best thing to take away from studies such as this is a target for new medicine and research: the goal of repairing and maintaining the human immune system in good condition for as long as needed. The various ways in which an immune system becomes damaged and poorly functional are becoming well known; researchers have enough to get started on doing something about this aspect of aging.

Technorati tags: aging, medical research

Posted by Reason at July 5, 2007 9:23 PM | TrackBack (1)