How is blood glucose control related to risk of fracture in people with diabetes?

How is blood glucose control related to risk of fracture in people with diabetes?

One of the rarely talked about complications of diabetes is its effect on bone health. According to various studies, people with diabetes have more fragile bones and are 2 to 3 times more likely to have a fracture compared to the general population.

The Diabetes – bone health Link

Type 1 diabetes is linked to low bone density (low bone mineral content), low bone quality, and higher bone fragility especially in the hip area, and in case of fall or trauma this can lead to fractures.

While the specific mechanism responsible for this fragility is still not completely understood, researchers believe that these factors are the most common in a type 1 diabetes context:

  1. In people with type 1 diabetes with diagnosis before adulthood, insulin deficit as well as some other hormones can affect bone mass and micro-structure thus making it more fragile.
  2. In some cases, diabetes can be associated with inflammation which could accelerate bone aging and thus susceptibility to fractures.
  3. Hyperglycemia was found to be associated with some bone abnormalities.
  4. Hypoglycemia can increase the risk of fall and accident thus increasing the risk of fractures.

Better blood sugar control and fracture risk?

Other than the relationship between diabetes and fracture risk, some researchers also looked at the relationship between blood sugar control and fractures.

However, they couldn’t reach a consistent conclusion as some found that the poorer the control the higher the fracture risk while others found no association or on the contrary found that a more stringent control, especially when HbA1c (glycated hemoglobine A1c) was very low which could indicate more frequent hypoglycemia, increased risk for fractures mainly by increasing risk of falls.

This lack of consistency is mostly due to the big variation in the methods used in the studies (e.g. too small number of participants, different ways to assess blood sugar control, etc.).

Interesting results from a new study

In a new study from the UK (1), the researchers evaluated the association between blood sugar control, using multiple hemoglobin A1C readings over time, and fracture risk in both people with type 1 (n= 3,329) and type 2 (N=44,275) diabetes separately.

They found that:

  1. The effect of glycemic control on the risk of non-vertebral (not including spine and skull fractures) low-trauma (occurring from trauma equal to or less than a fall from standing height) fractures differs between type 1 and type 2 diabetes, as they found better control to be associated with less fracture risk in type 1 diabetes but found no association in type 2.
  2. In type 1 diabetes, poor blood sugar control (average HbA1c levels over 8%) was associated with a slightly increased risk of fracture when compared to good glycemic control (HbA1c levels under or equal to 7%).

Bottom line:

While risk of a fracture increases with diabetes diagnosis, the good news is with adequate blood sugar control, there is a possibility to decrease this risk, especially in type 1 diabetes. Additionally, other factors such as maintaining a healthy lifestyle, with appropriate nutrition (e.g. good intake of calcium and Vitamin D) and physical activity, have a protective effect on the health of our bones.

Hypoglycemia prevention to reduce fall risk is another important precaution. Finally, when the bones are too fragile (osteoporosis) which is a frequent condition after the age of 60 years even without type 1 diabetes, treatments are available, and they do not interfere with glucose control.

Reference:

(1)Vavanikunnel J, Charlier S, Becker C, Schneider C, Jick SS, Meier CR,and Meier C. Association between Glycemic Control and Risk of Fracture in Diabetic Patients: A Nested Case-control Study. The Journal of Clinical Endocrinology & Metabolism, January 16, 2019. doi:10.1210/jc.2018-01879.