Dying of Old Age: An Old Wives' Tale?

Many people die at an advanced age--but does that mean that old age kills? Researchers are beginning to think that time can be toxic because aging makes us more vulnerable to disease.

Countless grandparents have "died of old age." But doctors remain woefully unable to explain how the advanced years kill poor Gram. In many cases, they attribute an elderly person's death to old age because no other obvious explanation emerges, says Tim Koelmeyer, a pathologist at Auckland University School of Medicine in New Zealand. As researchers look more closely at the problem, they're beginning to question whether old age itself is ever fatal. The answer is crucial: If scientists hope to extend human longevity, they'll need to pinpoint the factors that curb it. But without policies that encourage doctors to invest energy in chasing down the true cause of death in the very old, researchers won't know which diseases to focus on as they search for treatments that will lead to longer and healthier lives.

"There is certainly a fixed limit to the human life span as far as we can tell," says Linda Fried, a gerontologist at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. Still, the human body doesn't just grind to a halt after it reaches a certain age. In many cases, elderly deaths are pinned on old age because no one looked very hard for the true cause, says Andrea Berzlanovich, a forensic pathologist at the Institute of Forensic Medicine in Vienna. Berzlanovich has autopsied scores of people who died after age 80, and her work has led her to the conclusion that old age rarely, if ever, explains death. She recently submitted for publication a study in which she autopsied 40 centenarians who died at home. "They looked healthy and they seemed to be healthy," says Berzlanovich. "But they were not. We found disease in every case." Nearly 70% had cardiovascular problems. Others showed signs of respiratory illnesses.

In a separate study of 319 people who had died at age 90 or older, Koelmeyer showed that the very old are often felled by infection or by tears or ruptures in the aorta, the major vessel that moves blood from the heart. Although both Koelmeyer and Berzlanovich found that the cause of death in the elderly is identifiable--if one looks--they also found that more than one factor often triggers death. About 19% of the deaths in Koelmeyer's study had multiple causes, and Berzlanovich says that many of her "healthy" centenarians showed signs of numerous health problems.

Even if disease is ultimately to blame for a death, it's often preceded by a downward spiral that renders a person particularly vulnerable. Researchers are beginning to take a closer look at how this happens, and "One of the big clues is coming from new science on frailty," says Fried. Frailty is a condition associated with aging whose symptoms include weight loss, decreased muscle mass and strength, weakness, lack of energy, and reduced motor performance. The condition seems to spring from a general weakening of the body, including the skeletal, muscular, blood, and neuroendocrine systems. When people become frail, their response to psychological and physical stressors such as illness, injury, or anxiety falters, says Fried: "[Frailty] seems to be a strong predictor of who is going to die in [the] short term." The syndrome appears to be progressive, and if researchers can learn to identify its early stages, they might be able to find ways to reverse it before it triggers the fatal downward slide, she says.

But doctors don't have a very good track record in diagnosing even textbook diseases in the elderly--much less something as nebulous as frailty. Despite newfangled tests and expanded scientific knowledge, doctors misdiagnose their patients at roughly the same rate they did 100 years ago. Berzlanovich, who has conducted hundreds of autopsies in her career, estimates that doctors made an incorrect diagnosis in 30% to 50% of the patients she has autopsied. Her conclusion agrees with others: A 1995 review concluded that autopsies reveal unexpected major findings in up to 33% of cases. One reason that cause of death might be misdiagnosed in older folks is that advanced age can modify a disease's presentation, says Koelmeyer. The elderly often live with multiple chronic illnesses, which together can weave a complicated web of symptoms that is hard to untangle.

What's more, autopsies are rarely done on the very old, which makes it difficult for doctors to know the true cause of death or to learn from their mistakes. In 1983, the editors of the Journal of the American Medical Association declared war on the "nonautopsy," arguing that the procedure is vital to the fight to cut diagnostic errors. But so far they seem to be losing. In the 20 years since then, autopsy rates have hardly budged. Koelmeyer says that situation needs to change: "If nothing else, postmortem examination is quality control in medicine."

If autopsies were more common, Berzlanovich says that fewer deaths would be attributed to old age. Although the idea that grandma died of old age might appeal to many families, finding out her real cause of death might yield clues about how all of us could live longer.

Christie Aschwanden is a freelance writer in Zuoz, Switzerland. She hopes she lives as long--and dies as peacefully--as her paternal grandmother, who died in her sleep last year a few weeks shy of her 92nd birthday.