Those who live to be 100 may impart valuable information about avoiding disease.
By STEPHEN NOHLGREN
Published August 31, 2004
MIAMI - Mabel Welch Dague would never think to call herself a pioneer. Except for a weekly trip to the beauty shop, she keeps to the St. Petersburg apartment she shares with her 68-year-old son. She reads novels, breezes through newspaper crosswords and eats three squares a day.
Yet the fact that she passed her 100th year last November makes her a pathfinder that scientists have recently begun to appreciate. She represents a vision of the future, and it's looking rosier than most people would expect.
Old age usually is perceived as a steady decline into restriction and illness, centenarian expert Dr. Thomas Perls said Monday. But a decadelong study of people 100 and older shows quite the opposite. As often as not, these hardy souls live relatively disease-free and are more likely to experience a more sudden health decline in just the last few years and months of their lives.
"It's more the case of the older you get, the healthier you've been," Perls told the annual meeting of the Florida Council on Aging.
This finding could prove life-altering for everyone. By analyzing why the super-old age so well, scientists are gaining valuable information about avoiding the cancers, strokes and heart diseases that ravage younger people and cut short their lives.
Perls' New England Centenarian Study and similar work elsewhere have found, for example, that 100-year-old men are always thin.
Women "are physiologically stronger than men, so they can handle things better." Perls said in an interview. For every male centenarian, more than five females reach 100.
While an occasional bulky woman might pass the century mark (think Queen Mum), heavy men won't. They might smoke, drink even more and pack away potatoes like orphans. But their bodies are always lean, which supports increasing dietary and genetic evidence that fat, and how it is processed, plays a critical role in disease and aging.
Centenarians also handle stress well.
"They seem to do that naturally," Perls said. "They tend to be funny. They tend not to dwell on things. They don't internalize things that are stressful. A lot of them tend to be religious, and it may be that faith in God is an important mechanism for managing stress well."
Some 100-year-olds share an unusual gene structure. If scientists can develop a drug that mimics how those genes affect the body, they might prevent chronic disease and extend lives.
An extra 10 years
When Mabel Dague was born in 1904, neither electricity nor automobiles had reached her Iowa home. Life expectancy was about 46, held down by childhood diseases and suspect water supplies. When she retired to Florida in 1955, the average American lived to 63 or 64.
Now modern drugs and aggressive therapies have stretched average life spans to about 78, with men dying a few years earlier than women.
Even so, bad habits probably rob people of about a decade of quality living, Perls said.
"About 70 percent of the country is overweight and 30 percent are obese," he said. "Way too many people still smoke, way too few people exercise, particularly strength training, and diets in general are very conducive to obesity and vascular disease."
The proof? Seventh-day Adventists.
"They believe God gave them this great gift, this wonderful body, and to treat the body wrong is a sin," Perls said. "They are vegetarians; they exercise and stay away from alcohol, although probably a little red wine is good for you, and they tend to be thin and don't smoke."
A California study pegged the average Seventh-day Adventist life span at 88. The New England Centenarian Study, which has followed 1,500 centenarians and their children, found that Lawrence, Mass., had an abnormally high number of people in their 100s, Perls said. "Lo and behold, that was a pocket of Seventh-day Adventists."
Mice lack religious conviction, but researchers can put them on diets that would put a Seventh-day Adventist to shame.
At the University of Michigan, lab mice on extreme low-calorie diets are living about four years - 50 percent longer than their better-fed brethren. They also tend to avoid major diseases, including cancer, cataracts and arthritis. They enjoy stronger muscles and immune systems.
"It looks like the whole aging process is delayed," said professor Richard Miller, who studies aging in mice there.
The mice get special vitamin and protein supplements to keep up their strength. Their caloric intake is reduced until they drop to 60 percent of their normal body weight, although significant benefits begin showing up at the 75 percent level. In human terms, that would mean a 200-pound man would have to slim to 150 to see noticeable effect, and 120 to qualify as a super-ager.
Nobody is advocating a society of aging anorexics, not even People magazine. But if researchers can unlock the mechanisms at play, new drugs might produce the same results without sacrificing bananas Foster and tortellini with Alfredo sauce.
That's one thing that makes the dwarf mouse so interesting. A genetic defect makes it about one-third the size of normal mice. It lives 40 to 50 percent longer, avoids disease, eats normally and can be chubby in old age.
What it lacks is the ability to process a growth hormone called insulin-like growth factor (igf1), which is probably why it stays so tiny. Calorie-starved mice also produce less of the same hormone.
"This certainly suggests that one thing determining how long animals will live is how much ifg1 an animal has, with low levels being on the good side," Miller said.
Miller warned against the simplistic assumption that science just needs a drug that will reduce growth hormone production. Mechanisms and interactions down to the cellular level must be understood first.
The government should beef up aging research as a way to fight disease, Miller said. Fleas, worms, spiders and monkeys all have lived extremely long, healthy lives on low-calorie diets.
"We are a lot closer to slowing the aging process down than we are to curing cancer," he said. "There is no animal model at this point that can cure cancer, or prevent colon or breast cancer. But we are able to slow the aging rate down two or three decades. It works every time.
"The way to slow down cancer is to slow the aging process. That seems to be a secret only aging researchers are aware of."
HOW LONG WILL I LIVE?
The experts conducting the New England Centenarian Study have developed a calculator to estimate your life expectancy. It doesn't pretend to be precise, but it might help you identify habits you can change. Take the test at www.livingto100.com
FACTS ABOUT CENTENARIANS
In the industrialized world, about 1 of 10,000 persons is at least 100 years old. About 3,500 live in Florida.
They live remarkably disease-free lives compared to people who die in their 80s, with less heart disease, cancer and dementia. Rather than suffering lingering illnesses, they tend to decline quickly just before they die.
About five of six are women. The few men who reach age 100 tend to be healthier than female centenarians.
About 90 percent of them lived independently until age 92; 75 percent lived independently until age 95; and about 15 percent lived independently at age 100.
They usually have long-lived parents, siblings and children. They handle stress well, tend to stay in good humor and are usually thin, particularly the men.
Women who bear children past the age of 40 are four times more likely to reach 100 than women who do not.
Sources: 2000 U.S. Census, the New England Centenarian Study, the Gerontological Research Group.
