"What this study shows is that disease is not the best way to assess the health of older people," he said. "If you live long enough, you're going to pick up a lot of them -- diabetes, high cholesterol, high blood pressure, heart disease -- but, by themselves, they don't immediately make people feel bad."
"But when people go on to become disabled, that's the bad sign," he added. "Because it's disability that interferes with your life and your ability to thrive -- to be physically and mentally able to reach your potential. So really, these things we call diseases could be thought of as risk factors for disability. Because when people become disabled, that's when they become truly sick. And that's when they stop living long."
A separate study in the same journal from Brigham and Women's Hospital in Boston revealed that men who do not smoke and practice a healthy lifestyle -- involving regular, vigorous exercise and weight control -- are more likely to live to age 90 and beyond.
The finding was based on questionnaires completed in the early 1980s by almost 2,400 men (average age 72), 40 percent of whom went on to live past 90. The analysis also suggested that men aged 90 plus have better physical and mental function then men who die at a younger age.
For additional information on centenarians in the United States, visit the U.S. Census Bureau.
SOURCES: Thomas Perls, M.D., associate professor, medicine and geriatrics, Boston University School of Medicine, and director, New England Centenarian Study, Boston Medical Center; James S. Goodwin, M.D., professor, geriatrics, and director, Sealy Center on Aging, University of Texas Medical Branch, Galveston; Feb. 11, 2008, Archives of Internal Medicine