Aging happens to all of us, and is generally thought of as a natural part of life. It would seem silly to call such a thing a “disease.”
On the other hand, scientists are increasingly learning that aging and biological age are two different things, and that the former is a key risk factor for conditions such as heart disease, cancer, arthritis, Alzheimer’s disease, and many more. In that light, aging itself might be seen as something treatable, the way you would treat high blood pressure or a vitamin deficiency.
Those two are in the current International Classification of Diseases (ICD), a manual published by the World Heath Organization — but aging is not. The next revision of the manual is due out in 2018.
While there is no formal campaign to add aging to the official list of diseases, new medical discoveries have opened the discussion. For instance, after studies showed that metformin, a common diabetes drug, could extend lifespan in rodents, researchers went to the federal Food and Drug Administration in June and won approval for human trials of the drug’s anti-aging properties.
But there’s no assurance that the FDA would approve an anti-aging drug, even if the clinical trials are positive. The agency has never allowed such a drug on the market, because aging hasn’t been designated as a condition needing treatment.
Experts interviewed by STAT differ on whether aging should be viewed as a disease, the extent to which it’s treatable — and whether doing so can help people live longer. Here’s what they had to say.
Aging is a disease
Biophysicist Alex Zhavoronkov believes that aging should be considered a disease. His company, Baltimore-based Insilico Medicine, Inc., is working on technologies around drugs to treat age-related illnesses. Zhavoronkov said that describing aging as a disease creates incentives to develop treatments.
“It unties the hands of the pharmaceutical industry so that they can begin treating the disease and not just the side effects,” he said.
“Right now, [people] think of aging as natural and something you can’t control,” he said. “In academia, people take aging research as just an interest area where they can try to develop interventions. The medical community also takes aging for granted, and can do nothing about it except keep people within a certain health range.”
But if aging were recognized as a disease, he said, “it would attract funding and change the way we do health care.”
Aging can be cured
Aubrey de Grey also advocates going after aging itself. He is chief science officer for the SENS Research Foundation, which conducts and funds research on regenerative medicine.
“I don’t actually say aging is a disease,” he said. “Aging is bad for you, it’s a medical problem, but that’s just language.”
What matters, de Grey added, is understanding that aging is curable.
“It was always known that the body accumulates damage,” he said. “The only way to cure aging is to find ways to repair that damage. I think of it as preventive medicine for age-related conditions.”
De Grey added that he is intrigued by the skepticism he finds.
“It’s a curious thing, ” he said. “If you fix one disease of aging, that’s wonderful. If you fix two diseases, that’s wonderful.”
Our lifespan is limited
Leonard Hayflick, a professor of anatomy at the University of California, San Francisco, said the idea that aging can be cured implies the human lifespan can be increased, which some researchers suggest is possible. Hayflick is not among them.
“There are many people who recover from cancer, stroke, or cardiovascular disease. But they continue to age, because aging is separate from their disease,” Hayflick said. He added that even if those causes of death were eliminated, life expectancy “would still not go much beyond 92 years.”
In the 1960s, Hayflick found that human cells divide only 40 to 60 times, after which they stop — even when their division is paused and then allowed to resume. This discovery, called the Hayflick Limit, indicates that even if a drug like metformin were effective at suspending aging, the end game stays the same.
Aging is normal
Dr. Jonathan Flacker, an internist in geriatrics at Emory University Hospital in Atlanta, said aging is simply not the same as an illness.
“A disease is something not normal that some people get but not everybody gets,” he said. “The implication is that aging is abnormal and something nature didn’t intend.”
Flacker is not terribly impressed with age-slowing drugs like metformin, either.
“We’ll see,” he said. “The mechanisms that control aging are very fundamental and I think it likely that in trying to modify those pathways there will be some significant unanticipated consequences, but that’s why we have such studies in the first place.”