Your Body, Your Life: News from the Medical Campus

What’s up?
Nearly all centenarians, those who live to be at least 100 years old, do not become sick until the end of their lives — in effect, they save their “sick time” — providing new insight into the factors that may contribute to extreme longevity.

A study by researchers from Boston Medical Center’s New England Centenarian Study published in this month’s Archives of Internal Medicine found that death and age-related disease do not always go hand-in-hand — instead, it’s physical or cognitive function that makes the difference. The researchers surveyed centenarians, asking how old they were when they were diagnosed with age-related diseases, such as diabetes, heart disease, and Parkinson’s, and comparing their responses to scores on an independence and quality-of-life test.

What was found:
The researchers surveyed 739 centenarians — 523 women (aged 100 to 119 years) and 216 men (aged 97 to 113 years). Those who were less than 85 years at the onset of their disease were classified as “survivors”; those who were 85 years or older at the onset were classified as “delayers.” A subgroup, classified as “survivors of disease,” were the members of the survivors group who had experienced age-related diseases for more than 15 years.

In the survivors of disease group, 72 percent of the males and 34 percent of the females scored in the independent range on the Barthel Activities of Daily Living Index at the age of 97 or older. This test, which examines how independent a person is in his or her daily living activities, showed that many centenarians have not delayed morbidity, or the prevalence of age-related diseases, to the end of their lives, but they have somehow delayed the onset of physical and cognitive disability. “In centenarians, the presence of age-related diseases doesn’t indicate their level of stability,” says Stacy Andersen, a research assistant in BMC’s geriatrics department. “Two-thirds of centenarians seemed to delay or escape the diseases associated with aging, and then the one-third who were classified as survivors, because they got age-related diseases before the age of 85, seem to have the same level of physical and cognitive function as those who did not have the disease.”

The research also showed that although they are far fewer in number, male centenarians tend to have significantly better mental and physical function than female centenarians. “All of our findings seemed to have replicated other studies in that men were typically doing much better than females,” says Andersen, “but men were much less common than females.”

What it means and why it matters:
Eventually, researchers should be able to understand how to improve quality of life for the elderly by delaying cognitive and physical disability, even if the patient is compromised by age-related diseases. This could lead to better prognosis and therapies. “It showed us how important centenarians are to study,” Andersen says. “Living a long life is great, but most people don’t want to live extra years if it means more years of disability. We see that with centenarians this isn’t the case, because they’re actually able to compress disability until the end of their life.”

Word to the wise:
Andersen emphasizes that it’s important to remember that this study focused on a very specific group of people who may just be blessed with great genes. Not everyone has the ability to delay disability.

What’s next:
Researchers are now interested in examining the factors that help centenarians delay disability and escape the diseases associated with aging.

Where to find more:
The research was published in the February 2008 issue of the journal Archives of Internal Medicine. Read more about the New England Centenarian Study here.

Amy Laskowski can be reached at amlaskow@bu.edu.