The Scientist has a very nice article titled "The Longevity Dividend", about attempts to treat diseases of aging with preventative biotechnology.
Some people, including a proportion of centenarians, live most of their lives free from frailty and disability. Genetics plays a critical role in their healthy survival. Identifying variation in these subgroups of humans holds great potential for improving public health. For example, microsomal transfer protein (MTP) on chromosome 4 has been identified as a longevity modifier in a sample of centenarians; there is strong evidence linking a common variant of KLOTHO, the KL-VS allele, to human longevity; and it has been demonstrated that lipoprotein particle sizes promote a healthy aging phenotype through codon 405 valine variation in the cholesteryl ester transfer protein (CETP) gene.
The article argues that the aging population may yield a "dividend" in the form of greater productivity, but only if research can succeed in preventing or allaying the disabilities of aging.