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:
- Four out of every five centenarians are women. Despite the dramatic slowing
of death rates at the oldest ages over the past few decades, gains for men have
been smaller and men still lag behind women in attaining age 100. Projections
suggest that these differences will continue into the middle of the 21st
- The centenarian population, mostly non-Hispanic white today, will become
significantly more diverse in the coming years. Approximately 78 percent of
today's centenarians are white, a proportion expected to decrease to about 55
percent by 2050. The percentage of the older Black population is expected to
remain the same at about 13 percent, with the proportion of Hispanics rising
from 5.6 percent to about 20 percent and Asian and Pacific Islanders expected to
grow from about 3 percent to nearly 11 percent.
- Only about half of the centenarians counted in 1990 had completed some high
school or more. This compares with four out of five people aged 65 through 69
in 1990 with at least some high school. The impact of educational attainment, a
major determinant of health status, will be closely observed as the younger
group, or cohort, moves toward very advanced age.
- The nation's centenarians are concentrated on both U.S. coasts, with about 10
percent of the total number living in California and 8 percent making their
homes in New York. A state-by-state analysis shows that, proportionally, Iowa
has the highest percentage of centenarians among its own population, followed by
South Dakota. (This description reflects a June 16, 1999, Census revision to the
state-by-state section of the report.)
- Internationally, the U.S. may have the highest proportion of centenarians among people age 85 and older, although this comparison can only be made among countries with relatively good quality data. There are approximately 120 centenarians per 10,000 people age 85 and older in the U.S.. This finding is in line with research indicating that life expectancy after 80 is higher in the U.S. than in a number of other developed countries.
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.