Click to listen to an interview with Jack Hall and Michigan technology researcher Sarah Hoy
Millions of people around the world face reduced quality of life due to periodontitis, osteoarthritis, and osteoporosis. A new study sheds light on the association of all three chronic bone diseases evaluated from a unique perspective on Isle Royale's wild elk population.
The study, led by researchers at Michigan Technological University and Duke University and recently published in the journal Osteoarthritis and Cartilage, found that moose with periodontitis developed severe osteoarthritis and osteoporosis. Turns out it's much more likely.
“Many of the diseases that affect humans are not uncommon among other species,” says study lead author Sarah Hoy, assistant professor in Michigan Technological University's College of Forest Resources and Environmental Sciences (CFRES). The difference is that moose are not subject to many of the same disease risk factors as humans. For example, moose don't fight obesity, drink alcohol, or smoke cigarettes.
Periodontitis, osteoarthritis and osteoporosis are major global public health challenges, Hui said. “These diseases not only affect the daily lives of so many people, but also place a huge burden on health and social security systems. A better understanding of the factors that cause these diseases It is urgently needed.”
Periodontitis, the most severe form of what many people know as periodontal disease or periodontal disease, is caused by a bacterial infection of the gums and bone surrounding the teeth. In severe cases, it can lead to bone and tooth loss. Osteoarthritis is a progressive and often disabling disease caused by cartilage degeneration in joints such as knees and hips. Osteoporosis is a decrease in bone density. This occurs when the destruction of old bone exceeds the rate of new bone formation, resulting in bones becoming more fragile and more prone to fracture. As people age, they are more likely to develop these diseases.
“Doctors have suspected for decades that there was an important link between these three,” Hui says. “But studying associations between human diseases is complicated because the likelihood of developing a disease depends on whether a person is obese, smokes cigarettes, drinks alcohol, Because it can be influenced by a variety of risk factors, such as having a bad diet and good access to medical care.These risk factors make it difficult for doctors and scientists studying this disease to This makes it difficult for individuals to identify potential connections.”
In total, the study evaluated both the prevalence and severity of each disease in more than 2,000 elk that died between 1959 and 2021. Finding research samples was not difficult.
For more than 60 years, Michigan Technological University researchers have studied wolf and elk populations on Royal Island, a federally designated Lake Superior nature preserve and national park, as part of an ongoing study of wolf and elk populations. I've been collecting moose bones. Hoy and Michigan Tech's John Vucetich and Rolf Peterson are co-leaders of the wolf and elk study. Now in its 66th year, the study is the longest running predator-prey study in the world.
Peterson, who evaluated the new research, had access to a vast specimen boneyard, the world's largest collection of elk bones, just a step outside his summer quarters on the island.
Each year, researchers, students, and project volunteers discover moose carcasses while hiking around the island in the summer or during annual aerial surveys to survey wolf and elk counts in the winter. Researchers carefully examine the animals' bones for signs of periodontitis, osteoarthritis, and osteoporosis. Particularly interesting bones are collected for cleaning and further thorough examination in the laboratory.
Moose bones were essential to many important studies conducted on Isle Royale. In 2010, a study found a link between childhood nutritional deficiencies and arthritis in adult moose, adding to the growing body of research showing a link between poor diet and the likelihood of arthritis in humans. In 2022, researchers announced that wolves were more likely to kill moose with arthritis, thus keeping prey populations healthy. That same year, researchers determined the age of the oldest known moose ever recorded on Isle Royale by counting lines in the cementum of amputated teeth of a cow moose that died in 2018. was completed. She was 22 years old, and Peterson likened it to being “fine.” When converted to human age, it is “more than 100 years old.”
A new study shows that female elk with periodontitis are 88% more likely to have severe osteoarthritis and have severe osteoporosis than female elk without periodontitis. It turns out that the chances are more than twice as high. The results were similar in male elk, with males with periodontitis 60% more likely to develop severe osteoarthritis and three times more likely to develop severe osteoporosis than males without periodontitis. It was more expensive than that. The study also found that male elk were more likely to contract these diseases than female elk.
Although this study did not assess the cellular mechanisms underlying the association between these diseases, the authors suggest that periodontitis may be affected by the effects of periodontitis-causing bacterial pathogens on proinflammatory cytokines. It is speculated that this may increase the risk of developing osteoporosis and osteoarthritis. Proinflammatory cytokines are small proteins secreted by cells of the immune system. They can cause inflammation and tissue destruction, which can worsen the osteoarthritis process in the joints. These pro-inflammatory cytokines impair the cells in the body that grow and heal existing bone, while also increasing the activity of cells that destroy bone and cause osteoporosis.
Regardless of the underlying mechanism, the new study adds to a growing body of evidence suggesting that periodontitis increases the risk of developing other serious health conditions such as diabetes, stroke, cardiovascular disease, and pneumonia. Among other findings, the study highlights the importance of developing and maintaining good oral hygiene habits, Hui said. Because moose don't throw buckshot or go outside to smoke cigarettes, but they also don't brush and floss their teeth regularly or go to the dentist.
Hui said the findings demonstrate the benefits of pursuing unusual collaborations to solve vexing global health problems.
“Scientists often study the behavior and dynamics of wild animals in the wild, while doctors and scientists often study human diseases in medical research facilities,” she says. . “This study highlights the value of multidisciplinary efforts to better understand the relationships between diseases that can be applied across species.”
Study co-author Virginia Kraus of Duke University also recognizes the potential for collaboration across disciplines and species.
“As a rheumatologist who studies and treats humans with these diseases, I was very intrigued to discover that the disease is equally severe in moose,” she said. “These results highlight the validity of the concept of unitary medicine: humans who need to work together to effectively treat, prevent, and control diseases that affect both humans and animals. There are great similarities between medicine and veterinary medicine.”
