Female dogs that keep their ovaries longer also live longer, according to a study led by David Waters, DVM, executive director of the Gerald P. Murphy Cancer Foundation.
The findings, according to researchers at Purdue Research Park in West Lafayette, Ind., challenge almost four decades of standard operating procedures used in female pets as well as humans. It was the first investigation to look for a link between retained ovaries and exceptional longevity in mammals, the researchers said.
“A female survival advantage in humans is well-documented—women outnumber men by 4-to-1 among those who reach 100,” said Dr. Waters, associate director of Purdue University’s Center on Aging and the Life Course.
“Like women, female dogs in our study had a distinct survival advantage over males. But taking away ovaries during the first four years of life completely erased the female survival advantage. We found that female Rottweilers that kept their ovaries for at least six years were four times more likely to reach exceptional longevity compared to females who had the shortest lifetime ovary exposure.”
The researchers collected and analyzed lifetime medical histories, ages and causes of death for 119 canine “centenarians”—Rottweilers living in the U.S. and Canada that survived to 13 years, about 30 percent longer than the average Rottweiler. These dogs were compared to 186 Rottweilers that had usual longevity, about nine years.
“Clearly we have tapped into a unique resource with our Exceptional Longevity Database,” said Waters, a professor in Purdue’s Department of Veterinary Clinical Sciences. “We like to think of it as the pet dog equivalent of the New England Centenarian Study. We want to better understand the biology of aging. Our quest to validate pet dogs as a model for the study of healthy human aging is at the core of this research.”
The dog study mirrors research from the Nurses’ Health Study, which evaluated more than 29,000 women who underwent a hysterectomy for benign uterine disease. The findings showed that the upside of ovary removal—protection against ovarian, uterine and breast cancer—was outweighed by increased mortality from other causes. As a result, longevity was cut short in women who lost their ovaries before age 50 compared with those who kept their ovaries for at least 50 years.
“For the last 35 years most doctors have been routinely advising women undergoing hysterectomy to have their ovaries removed to prevent ovarian cancer,” said William Parker, MD, of the John Wayne Cancer Institute, who published the study. “We believe that such an automatic recommendation is no longer warranted.”
Taken together, the emerging message for dogs and women seems to be that when it comes to longevity, it pays to keep your ovaries, according to Purdue Research Park.
“What we have here is a compelling convergence,” Waters said. “The data from women and dogs, together with reported longevity benefits from ovary transplants in mice, are pointing in the same direction: the notion that a network of processes regulating longevity is under ovarian control.”
The dog study was published in Aging Cell.
The Gerald P. Murphy Cancer Foundation, based at Purdue Research Park, is home to the Center for Exceptional Longevity Studies, which tracks the oldest living pet dogs in the U.S.
This article first appeared in the February 2010 issue of Veterinary Practice News