Biomarkers are an important part of the medical diagnostic toolkit. Diagnostics isn't as flashy as the search for a cure, but bear in mind that many age-related conditions could be ameliorated or avoided entirely if predicted or otherwise caught in very early stages. EurekAlert reports on the identification of a biomarker for osteoarthritis: "a chronic degenerative joint disease, osteoarthritis (OA) is a common cause of pain and disability among older Americans. OA of the knee affects up to 6 percent of the older population, while OA of the hip affects about another 3 percent. While treatments vary, there is hope that early intervention - before joint destruction can be clearly seen and measured on an X-ray image - will improve outcomes."

Link: http://www.eurekalert.org/pub_releases/2005-01/jws-abt010705.php