The number of centenarians in the U.S. is growing rapidly, according to a new report from the U.S. Census Bureau. During the 1990s, the ranks of centenarians nearly doubled, from about 37,000 counted at the start of the decade, to more than an estimated 70,000 today. And analysts at the Census suggest that this per-decade doubling trend may continue, with the centenarian population possibly reaching 834,000 by the middle of the next century.
The report, funded by the National Institute on Aging (NIA) at the National Institutes of Health, does point out significant problems with information on the true ages of people 95 and older, though the data are becoming more accurate with improvements in birth records. But as scientists work to improve data quality, the trends in the growth and characteristics of the very elderly are now becoming evident, say NIA experts, as researchers intensify their study of this population.
"We are increasingly interested in the lives of these remarkable people," notes Richard M. Suzman, Ph.D., Associate Director of the NIA for Behavioral and Social Research. "The growing numbers of extremely old people give us the opportunity to examine their lives in more detail. By doing so, we will be able to discover the genetic, medical, social, and behavioral factors contributing to longevity and robustness in very advanced age."
Suzman points out that scientists will be watching mortality rates of people over 50 very carefully to see if projections about the growth in the elderly population, including centenarians, can be refined. The Census estimates range from projecting a low of 265,000 centenarians in the year 2050 to a high-end calculation of about 4.2 million. Its "middle series" projection is 834,000.
According to the report, the centenarians share many of the characteristics that Census and other researchers have noted for people age 85 and above. Most significantly:
Data from the report, Centenarians in the United States, P23-199, will be available at www.census.gov/prod/99pubs/p23-199.pdf  (PDF, 1.5M), the Census website. It will be posted June 16.
The report is the latest in a series of joint demographic projects by the Census Bureau and the NIA to characterize the elderly population and examine its dynamic growth in the past and as projected into the next century. It was prepared by Victoria A. Velkoff, who heads the Aging Studies Branch at the Census Bureau.
Specifically on the very elderly, the NIA has supported other research projects, including a Massachusetts study of centenarians by Thomas Perls, M.D., M.P.H., of Harvard University and a study of centenarians in Europe and China by James Vaupel, Ph.D., of Duke University and the Max Planck Institute in Germany.