People who have type 1 diabetes (T1D) are at greater risk of having bone fractures. But why?
Until now, the working hypothesis was that the nerve damage, or neuropathy, that is a common side effect of diabetes (and even more frequent in T1D), was the major contributor to the bone fracture risk. But a just-published study from investigators at the University of Sheffield in the United Kingdom indicates that there might be more to it than that. The research was published in the Journal of Bone and Mineral Research.
The researchers said that although several studies have studied bone microarchitecture in diabetes, most of these studies were done on type 2 diabetes and “data on T1D are scarce.” In addition, they said, “no study has investigated the effect of diabetic neuropathy on the skeleton.”
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The researchers recruited patients with T1D from diabetes clinics and from research participant lists in Sheffield between October 2017 and October 2018.The subjects were older than 18 and had T1D for more than five years. In all, the researchers enlisted 60 people and divided them into three groups. The first group consisted of 20 T1D patients who had what’s known as distal symmetric sensorimotor polyneuropathy, which is probably the most common type of nerve damage associated with diabetes. Its most frequent characteristic is progressive damage to the toes and feet. The second 20-person group consisted of people with T1D who did not have nerve damage, and the final group of 20 were “healthy controls” who did not have diabetes.
Once the subjects were recruited, the researchers gave them a series of tests to evaluate their bone health as well as their muscle mass. The patients were also examined for any signs of neuropathy and were reviewed for their muscle strength, their gait, and their balance. The patients were also tested for bone porosity. Cortical bone is the heavy outer protective surface of bones, and, according to the authors, a condition known as cortical porosity has been shown to be the main bodily feature affected by diabetes. As the term indicates, a bone porosity test measures how porous a bone is on a “microarchitecture” level.
Several factors appear to contribute to fracture risk
Not surprisingly, the researchers found cortical porosity to be higher in patents with T1D than in patients who didn’t have T1D. Also, previous fractures were more common in the T1D patients who had some form of neuropathy. Nevertheless, the researchers also determined that although T1D and diabetic neuropathy affect bone structure, these conditions do not completely account for the higher risk of fracture in T1D patients. According to the researchers, the risk of fractures in T1D appears to result from several factors or causes, or, to use their term, the risk is “multifactorial” — that is, it involves both skeletal and nonskeletal features. For example, the researchers reported that the patients with T1D “had worse performance in tests that assess not only muscle strength but also balance and gait.” According to the study’s lead author, Tatiane Vilaca, MD, of the University of Sheffield, “It is important to investigate what leads to an increased risk of fractures in type 1 diabetes. Our results suggest that in addition to bone features, balance and muscle strength also play a role. These findings could help improve approaches to fracture prevention.”
These findings follow research conducted by the same team of scientists and published in 2020. At that time, they remarked that diabetes patients in general might not be fully aware of their risk of fractures. As Dr. Vilaca then said, “Diabetes can cause a number of well-known complications including kidney problems, loss of eyesight, problems with your feet and nerve damage. However, until now many people with diabetes and their doctors are unaware that they are also at greater risk of bone fractures. We need to raise awareness about the greater risk people with diabetes face to help them to prevent fractures. For example, preventing falls can reduce their risk of fracture. Fractures can be very serious, especially in older people. Hip fractures are the most severe as they cause such high disability.”