Oldest-living Dogs Provide Clues to Human Aging
What does it take to live to 100? Scientists in the field of aging research have, for obvious reasons, studied the oldest-living humans. But now they are looking at a powerful new key to potentially unlock the secret to longevity: It has been observed that when it comes to aging and cancer, pets and people have a lot in common. Could the oldest dogs turn out to be our greatest teachers?
A study conducted by scientists at the Gerald P. Murphy Cancer Foundation's Center for Exceptional Longevity Studies reports that exceptional longevity in pet dogs is associated with gender and profound disease resistance. The results were presented at the ninth annual meeting of the Organization for the Study of Sex Differences at Stanford University.
"In this first study of exceptional longevity in pet dogs, we discovered a female longevity advantage of 5:1 over males in dogs that achieve the most extreme longevity," said David J. Waters, DVM, Ph.D., the scientist who led the study.
Waters is director of the center, based at the Purdue Research Park in West Lafayette, Indiana. The center is home to the Exceptional Longevity Database, the first systematic study of highly successful aging in pet dogs. Waters' research team has cataloged the lifetime health and medical histories of more than 300 canine "centenarians." The study focused on Rottweilers who lived at least 13 years, which is more than 30% longer than the breed average, and equivalent to humans reaching 100.
The investigators found that canine centenarians display profound resistance to cancer, with a cancer mortality rate of only 8% in dogs with the most extreme longevity, compared to more than 70% in dogs with usual longevity.
"A notable aspect of highly successful aging is the delay or avoidance of age-related diseases, such as cancer," Waters said. "The exceptionally long-lived Rottweilers we are studying have figured out how to side-step cancer, hold it in check. Our autopsy studies are showing that although relatively few of these dogs die of cancer, more than 90% of them are harboring one or more types of cancer at the time of death."
Like in humans, the study is showing that exceptional longevity in dogs is accompanied by what researchers refer to as "morbidity compression," or a squeezing of major age-related diseases into the final years of life. Among dogs with the most extreme longevity, 76% are "escapers" -- free of all major diseases for the equivalent of the first 100 years of life.
The new data on the female longevity advantage in dogs complements a growing catalog of human sex and gender differences in biology and health, ranging from susceptibility to autoimmune disease and cancer, to adverse drug effects and the symptoms of heart attack.
Waters put the new study in perspective, noting that for centuries dogs have enriched people's lives in important ways as our pets and our companions. Now, for the first time, the oldest-living dogs are being investigated with the hope that their extreme natural biology will offer up fresh scientific clues.