Texas A&M Researchers Target Hidden Link Between Diabetes, Obesity And Bone Healing

More than 100 million people in the United States have obesity, a condition linked with diabetes, cardiovascular disease, strokes and nerve damage. Among the states with the most obesity cases, Texas ranks No. 10.

With prevalence of the disease expected to rise by 2050 — when one-third of children and adolescents are expected to be overweight or obese — researchers are racing to uncover new treatment options to benefit this ever-growing population.

In this quest, research recently revealed a link between obesity, diabetes and poor bone fracture healing.

“People with Type 2 diabetes and obesity are more susceptible to bone fractures; their bones don’t heal at normal rates, or sometimes at all,” said Dr. Srividhya Iyer, an assistant professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences’ Department of Veterinary Physiology and Pharmacology.

Having a bone fracture that won’t heal often leads to surgery and can lead to amputation, a procedure that more than 160,000 American diabetics undergo each year, according to the American Diabetes Association.

Now, with a $1.6 million grant from the National Institutes of Health, Iyer and her team will spend the next three years researching the relationship between diabetes, obesity and bone fractures. They hope to develop a treatment that can help stubborn bone fractures heal, thus preventing further complications and improving quality of life for people with diabetes and obesity.

Bone Health And Diabetes

Until recently, bone health has not played a large role in the conversation around diabetes and obesity.

“We know that individuals with excess weight have a predisposition to develop Type 2 diabetes and cardiovascular problems,” Iyer said. “What has not been appreciated is that they also have weaker bones, which increases the chance of fracture.”

But the complications don’t end there. Not only are people with obesity or diabetes more likely to break a bone, but their bones also take longer to heal — if they do at all.

“Normally, if you break a bone, you receive a cast for four weeks while the fracture heals,” Iyer said. “But if you have Type 2 diabetes or obesity, you are likely to be in the cast for longer, which means having a temporary disability for longer, affecting your quality of life.”

Because the differences between healthy bones and weakened ones don’t show up in standard X-rays and bone mineral density tests, the full problem is only now starting to be recognized by the medical research community based on statistics of people with bone fracture complications.

“When a broken bone does not heal properly, there is pain and swelling in addition to what a patient may normally experience from a fracture,” Iyer said. “Most doctors will recommend surgery at that point, and if that does not work, then the only option may be amputation.

“All of these steps cost time, money and quality of life for the patient, which is what we are trying to prevent,” she said.

Illuminating The Black Box

To find a solution for stubborn bone fractures, Iyer and her team are investigating the underlying mechanisms that affect bone repair.

“When you get injured, there are certain cells that wake up and begin to repair the break, whether it’s a bone fracture or a skin abrasion,” Iyer said. “They create a kind of ‘glue’ or bridge across the fracture, which then ‘cements’ the injury so there’s no evidence that there was a break.

“But in people with diabetes or obesity, the process either takes longer, doesn’t work at all or pauses at a certain stage. We really do not understand what the problem is — it’s a black box,” she said. “There is some process that needs to be corrected. Are the cells not making enough material to bridge the fracture? Is there something breaking down the bridge? Figuring out what’s going on is what this grant is about.”

Fighting Long-Term Risks

One of the problems with obesity and diabetes-related bone weakening is that the problem persists even if an individual’s diabetes is under control.

“Even when blood sugar is stable with medication, a person can have low rates of bone healing and the chances that they don’t heal are three to five times higher,” Iyer said. “The chances of needing to undergo a follow-up surgery for musculoskeletal complications also rises. There is even an increased mortality risk because of the chance of bacterial infections or sepsis in a part of the body that cannot be amputated.

“What used to be a problem common in elderly populations now affects people of all ages,” she said. “It has consequences for Texans, the U.S., and the world.”

Providing Hope

The good news is that Iyer and her team are working hard to uncover treatment options for  people who have trouble healing fractures. One part of the grant involves testing therapeutic drugs to see if the researchers can “trick” stubborn bones into healing like they would in a lean person.

“We know that obesity and Type 2 diabetes are associated with certain changes in the body, like higher blood glucose, insulin resistance and the altered sentinel functions of the cell, which look out for threats. It’s possible that these factors are acting preemptively to suppress the healing process,” Iyer said. “We hope that there may be a drug that can encourage these systems to operate normally.”