A team of researchers from the University of Sheffield and Sutter Health have found that diabetes is associated with an increased risk of bone fractures.
Diabetes is known to be associated with an increased risk of fractures, but previously it was unclear why this was the case. Hip fractures are particularly dangerous and can cause lifelong disability and death. Researchers from Belgium and the US found that the risk of death in the first three months after a hip fracture is between five and eight times higher than would normally be expected. Furthermore, 20% of patients die within the first year following a hip fracture, and less than half regain normal mobility.
People with diabetes are not only at a higher risk of hip fractures but also have an even higher risk of death following a hip fracture. There have been numerous studies attempting to explain the link between diabetes and bone fractures, but these solely focused on vertebral fractures, rather than a broken hip, wrist or humerus. They also failed to include important features in their analyses including age, body mass index (BMI), diabetes duration and insulin use.
The team of researchers from Sheffield and Sutter Health focused on non-vertebral fractures, in hopes of identifying the causes behind increased bone fracture risk. Analysing both Type 1 (T1D) and Type 2 (T2D) diabetes, the researchers found that in both types the risk of hip fractures was significantly higher in young female insulin users as well as those with a longer disease duration.
The scientists began to sift through possible causes for the increased fracture risk in diabetics. Patients with diabetes are more likely to experience a fall; especially those using insulin and who have hypoglycaemic (low sugar) episodes. Those with chronic hyperglycaemia (high sugar), on the other hand, may have altered bone material. High levels of glucose interact with proteins in the body to produce Advanced Glycation End products (AGEs) which can accumulate and decrease bone strength.
Antidiabetic drugs themselves may also enhance the risk of bone fractures, although the data is inconsistent in some places. Some drugs, namely sulfonylureas or metformin, have no direct effect on bone but may increase the risk of fractures by causing greater risk of falls or hypoglycaemic episodes. Others promote the production of fat (adipogenesis) and impair the production of bone cells (osteoblastogenesis), which weakens bone and makes it more prone to fractures.
What particularly interested the scientists was that the effect of diabetes on bone fractures was particularly prominent in people under the age of 65. The researchers concluded that at a younger age, the relative risk of diabetes-associated fractures is higher than age-related fractures. As a person ages, their age becomes a huge factor influencing the likelihood of bone fractures, and the additional risk of diabetes is less important.
Analysis of other factors found that obesity is actually associated with a lower risk of fractures due to mechanical and hormonal mechanisms. Scientists are still unsure why the risk of fractures in people with T2D is so high despite the high prevalence of obesity in this disease.
