washingtonpost.com  > Health > Special Reports > Aging Well

Looking Ahead to The Days of Old

As Centenarians Multiply, Scientists Pursue Clues to Oldest Age. Hint: It's Not Just Genes

By Rita Zeidner
Special to The Washington Post
Tuesday, October 5, 2004; Page HE01

The tattoo on Lloyd Brown's right arm, marking his tour on the USS New Hampshire, is faded. But his memory of the day he was sworn into the Navy is not.

"Yep, April 6, 1918," he says, clearly pleased with his powers of recall that at other times have proven a bit spotty. The military records his daughter, Nancy Espina, keeps in a scrapbook at Brown's home in Charlotte Hall, Md., confirm the date.

Once considered a medical curiosity, centenarians like Lloyd Brown, 105, are the fastest growing segment of the U.S. population. (James M. Thresher - The Washington Post)

_____From The Post_____
How Long Might You Stick Around?
_____Aging Well_____
A New Vision For Midlife?
Looking Ahead to The Days of Old
A Physical Escape
Nursing Home Costs
A Head Start on a Healthy Old Age

Brown, who turns 105 on Thursday, can recall much of a remarkable life that has spanned three centuries. Among his most vivid days are those he spent on Navy ships -- the first aboard the coal-burning New Hampshire, guarding the North Atlantic during the final years of World War I. "Holystoning," a laborious process sailors of his era used to keep the decks clean of coal dust, made a lasting impression.

"We'd take some sand and push it around with a brick all day," he recalls.

His second naval tour took a more leisurely pace: playing the cello in the admiral's orchestra aboard the USS Seattle during the Roaring '20s.

Brown would spend most of the '30s and '40s as a fireman for Engine Company 16 -- when the three-story firehouse at 13th and K streets "was the tallest building on the block," he says.

Once considered a medical curiosity, centenarians like Brown are the fastest growing segment of the U.S. population, according to the Census Bureau. Numbering about 71,000 today -- a 35 percent increase since 1990 -- their ranks are expected to swell tenfold over the next 40 years and to leap past a million once the first baby boomers come of age in 2046.

Their representation in the larger population also is building. In the early 1900s, only about 1 in 100,000 lived into the triple digits; now it's about 1 in 10,000.

"Centenarians are raising the bar for all of us," said geriatrician Thomas Perls, director of the New England Centenarian Study, a Boston University-based research project launched 10 years ago to examine factors that may contribute to extreme longevity worldwide. "People who are 80 or 85 aren't so old anymore."

Today, Brown spends most of his days padding around his one-story rambler, where, by choice, he lives alone. A caretaker helps him with bathing, and Espina drops by daily to chat and bring him meals. Weather permitting, Brown will hop into his golf cart and drive across his lawn to pick up his mail. For the most part, though, he prefers to stay indoors and read the paper or watch TV news. He doesn't care much for fictional dramas.

"I have trouble following the story line," he says. "Too many characters."

He still has a driver's license but, to his daughter's relief, hasn't taken his car out lately. He's taken the golf cart down Route 5 instead.

"He headed out to the veterans hall," Espina recalls. "He wanted to see what was going on."

Growth in the number of centenarians like Brown can be partly explained by better care of the very young -- and a corresponding decrease in infant mortality. But myriad other factors -- among them education, environment, genetics and diet, not to mention dumb luck -- also contribute to longevity.

Perls, along with researchers crossing the boundaries of traditional scientific disciplines, hope to gain a better understanding of how much of that advantage is attributable to good living and how much to good genes.

"Living to 100 is basically like hitting the lottery," said Perls. "You have all these factors, but, like lottery numbers, they have to line up in the right way."

Collecting Clues

Though we all know of instances where longevity seems to run in the family, a series of recent studies downplays the role of genetics, emphasizing instead the role of good habits learned at an early age.

A landmark study of Swedish twins published in 1998 calculated the likelihood that longevity was inherited at 20 to 30 percent. Put another way, behavioral and environmental factors, including whether the participants smoked or were overweight, accounted for at least 70 percent of the variations in age at death.

The message was underscored by a 2001 study of 34,000 Seventh-Day Adventists in California. After tracking participants for 12 years beginning in the 1980s, researchers linked five common Adventist lifestyle practices -- such as regular exercise, a vegetarian diet and consumption of small servings of nuts five to six times a week -- to a longer-than-average life expectancy.

Scientists calculated that the life expectancy of a 30-year-old vegetarian Adventist woman was 85.7 years, and 83.3 years for a vegetarian Adventist man. This exceeded the life expectancies of other Californians by 6.1 years for women and 9.5 years for men.

"This was a group of people that were doing everything our mothers tell us to do, except for cleaning our plates," said Perls.

Meanwhile, life expectancy fell nine to 10 years for Adventists who were overweight, former smokers and non-vegetarian, and who did not exercise or eat nuts regularly.

But other research, including some that stems from data collected through the Centenarian Study, argues for the familial link -- a theory consistent with the experience of Brown and his kin. Though two siblings died in their eighties, his older sister died two years ago at 105.

The same year findings were published on the Swedish twins, Perls showed that people with a centenarian sibling have a four to five times greater chance of living to age 91 than people whose siblings died in their seventies. Later he discovered that men with a centenarian sibling were 17 times more likely to reach 100; women with a centenarian sibling were 8.5 times as likely to reach triple digits.

The findings don't necessarily contradict the Swedish study; rather, it might be that an improved shot at only extreme longevity -- living past 100 -- is shared among siblings, according to Perls.

"To get to your 100's, that formula might be different," he says.

Scientists are just beginning to gain insights into how genetics enters into the longevity equation. Not all centenarians follow the Adventist model -- Lloyd Brown continues to puff on a pipe daily, a habit he picked up decades ago. Plus, even as a young father, he was far more likely to pick up his cello than a football, according his daughter, still a relative youngster at 64.

The Genetic Factor

Today there is growing evidence that not one but various biogenic forces may work together -- either to prevent some of the ravages of aging or to assist in damage control. At least some of these genes, it seems, are passed down.

"Nobody thinks there's going to be [just] one gene that leads to longevity," said Evan Hadley, associate director for geriatrics at the National Institutes of Health.

In 2001, a team from Harvard and two Boston hospitals identified a region on Chromosome 4 -- one of 23 chromosomes that make up the human genetic blueprint -- that is likely to contain a gene or genes associated with extraordinary life expectancy.

Subsequent studies led to the discovery that a gene called microsomal transfer protein (MTP) was responsible for the link between the chromosomal region and longevity. This gene plays an important role in cholesterol transport and one variation of the gene, common among the centenarians in the study, decreases one's risk for cardiovascular disease.

"It is not a surprise," said Perls, "that we would find a gene related to cardiovascular health since heart disease is the number-one killer among older people. Centenarians must have increased resistance to this and other age-related diseases in order to achieve their remarkable ages."

In the early 1990s studies with tiny worms at the University of California at San Francisco showed that a single mutation in the daf-2 gene doubled the worms' life span. More recently, UC researchers extended the worms' life span sixfold. Researchers hope the findings may one day lead to human therapies that address oxidative damage (cancer and cardiovascular disease, for instance) and protein aggregation (diseases such as Parkinson's, Alzheimer's and Huntington's).

Adding one more piece to the genetic puzzle, researchers at the Albert Einstein College of Medicine in New York last year found that centenarians tend to have super-sized cholesterol molecules. Smaller particles, researchers now believe, are more easily embedded in the blood vessel walls and contribute to the fatty buildups that lead to heart attacks and strokes.

The study, published in the Journal of the American Medical Association, suggested that the trait of over-sized cholesterol is inherited.

Healthy to the End

If the pickings seemed slim for women seeking male partners during the conventional dating years, the prospects only get poorer: Fewer than 20 percent of centenarians in the United States today are men, a statistic expected to remain relatively unchanged over time.

Worldwide, the differential is even more pronounced, with women centenarians outnumbering men by about 9 to 1. The only exception appears to be in cultures that subject women to practices such as female infanticide and bride-burning, says Perls in his book, "Living to 100: Lessons in Living to Your Maximum Potential at Any Age" (Basic Books, 1999).

The small consolation is that those men who do see 100 will most likely be in better cognitive and physical shape than women their age, says Perls. Why is unclear, but one theory holds that in light of men's shorter life spans, those who do make it to 100 must be particularly hardy.

In any case, data collected through the centenarian study tends to shatter the stereotype of the long-suffering geezer. In fact, the profile of centenarians emerging from the New England study is that of lives spent, for the most part, in exceptionally good health, with sickness or frailty only near the end.

"It's the idea that the older you get, the healthier you've been," said Perls.

That's been the pattern for Brown, who but for a gallbladder flare-up decades ago and a hip broken after a fall in the early 1990s -- when it was discovered he had exceptionally strong bones, despite the fracture -- never spent a day sick in bed.

His daughter, who admits to having a long list of health issues, jokes, "The doctor tells me to come back in six months. He says to my dad, 'I'll see you in a year.' "•

Rita Zeidner recently wrote for the Health section about hands-free technology for those with injuries or disabilities.

© 2004 The Washington Post Company


Clinical Trials Center

  •  Cosmetic & Beauty Services

  •  Hospitals & Clinics

  •  Men's Health Care

  •  Women's Health Care