The New England Centenarian Study is an attempt to find and recruit all the centenarians (and their families) living in eight towns surrounding and including Boston, Massachusetts. As such, it is the only population-based study of centenarians in North America. By choosing a circumscribed population and enrolling approximately all the centenarians in that area, we do our best to prevent selection bias in the study and therefore obtain a valid and representative picture of centenarians living in the northeastern United States.

We are always hopeful that prospective subjects and their families will contact us via this Web site. If you or a family member(s) or an acquaintance(s) may be eligible to participate in one of our studies, please contact us.

The population size of our study area is 460,829 people and it is made up of the following towns: Belmont, Cambridge, Somerville, Dedham, Quincy, Framingham, Waltham, and Lexington. We chose these particular towns because of their local proximity to the Harvard Division on Aging and our preliminary work indicating the high sensitivity of their censuses in listing centenarians. These censuses are nearly 100 percent sensitive (and detect all the centenarians in the population) and about 30 percent specific (30 percent of the centenarians detected are alive). We have verified the ages of 46 centenarians living in this area. Therefore, the prevalence rate, as of December 31, 1996, was about one centenarian per 10,000 people. This translates into about 650 centenarians for the state of Massachusetts. This demographic study of the ability to verify ages and to determine prevalence appears in the March 1999 issue of Age and Ageing.

Soon we will begin a new round of recruitment, including the city of Boston, essentially doubling our sample size to a pproximately 100 centenarians at any one time and including many more minority participants.

Estimates for the number of centenarians in the United States hover around 50,000 though if one applies a rate of 1 per 10,000 to the country as a whole, the prevalence would be closer to 30,000. Because centenarians are the fastest growing segment of our population, there will be many more of them in the near future. By the middle of the next century, with the continuing aging of the baby boomers (73 million strong), estimates for the number of centenarians range from 500,000 to five million!

Neuropsychological and neuropathological assessment

We are assessing the cognitive function of our subjects because we believe that Alzheimer's disease is either markedly delayed or even absent in some subjects. This is based upon the premise that people have to be very healthy the vast majority of their lives in order to successfully reach age 100. Because Alzheimer's is a lethal disease over the course of 8-10 years, if one is going to develop this disease and still make it to 100, one would have to develop it no earlier than in their nineties. Approximately 30 percent of our subjects consent to donate their brains for detailed study after they have passed away. In this way we can correlate how the person was doing cognitively while alive, with what their brain looks like. Our collaborators in this effort include the Alzheimers Disease Research Center at Massachusetts General Hospital: Marilyn Albert Ph.D., Kathy Newell M.D., Bradley Hyman M.D., Ph.D., John Growdon M.D., and T.Hedley-Whyte M.D. We report the results of this neuropsychological-neuropathological correlation in the January 1999 issue of the Journal of the International Psychogeriatrics. Our work in this area was also noted in the January 24-31, 1998 issue of The Economist, and the March 5, 1998 issue of the Harvard Gazette.

Many people believe dementia is an inevitable consequence of aging. If this were the case one might expect all centenarians to have dementia. We have found three centenarians who were completely cognitively intact at the time of death and their brains appeared entirely normal without the typical neuropathological markers of dementia, especially those of Alzheimer's disease. Thus, at least some people can live to extreme old age without dementia.

We are in the process of proving that centenarians either escape or at least markedly delay the onset of Alzheimer's disease. The next important question is how are they able to do this? Therefore, we are now conducting a molecular genetics-based search for the genes that impart protection and/or the genes that are absent which would cause or increase the susceptibility for the disease. We are already taking this next step in another aspect of our work: The Centenarian Sibling Pair Study.

Margery H. Silver Ed.D., the Associate Director of the New England Centenarian Study, heads the neuropsychological assessment of our subjects.