Bad Blood Sugar and Broken Bones

Type 2 diabetes control linked to fracture risk

(RxWiki News) Having denser bones typically means having stronger bones. However, diabetes patients have a higher risk of fracture even though they have higher bone density. Could blood sugar control influence this risk?

A recent study showed that poorly controlled blood sugar may increase the risk of fracture among patients with type 2 diabetes.

Results showed that diabetes patients with poor blood sugar control had a 47 to 62 percent higher fracture risk than those without diabetes and those with adequately controlled blood sugar. Patients with adequately controlled blood sugar had a similar risk as those without diabetes.

"Control your blood sugar to help prevent complications of diabetes."

Fernando Rivadeneira, MD, PhD, of Erasmus Medical Center in the Netherlands, and colleagues set out to study the link between blood sugar control and skeletal problems.

"Individuals with type 2 diabetes have increased fracture risk despite higher bone mineral density. Our aim was to examine the influence of [blood sugar] control on skeletal complications," the authors wrote.

The study included 4,135 participants. The 420 participants with type 2 diabetes were grouped according to their blood sugar control using HbA1c - a measure of blood sugar over the past three months. The first group consisted of patients with adequately controlled blood sugar (HbA1c of less than 7.5 percent). The second group consisted of patients with poorly controlled diabetes (HbA1c of 7.5 percent or more). The third group included those without diabetes.

Researchers measured different bone characteristics, including bone mineral density, cortical thickness and thickness of the femoral neck.

Bone mineral density is the amount of mineral matter in the bones. Lower bone mineral density - like that which occurs in osteoporosis - is often a sign of weak bones. Cortical thickness is the thickness of the tissue that forms that outer shell of most bones. The femoral neck is the part of bone just below the hip joint.

Compared to participants with adequately controlled blood sugar and those without diabetes, diabetes patients with poorly controlled blood sugar had:

  • 1.1 to 5.6 percent higher bone mineral density
  • 4.6 to 5.6 percent thicker cortices
  • 1.2 to 1.8 percent narrower femoral necks

Patients with poorly controlled blood sugar had about a 47 percent higher risk of fracture than those without diabetes and about a 62 percent higher risk than those with adequately controlled blood sugar.

"Poor [blood sugar] control in type 2 diabetes is associated with fracture risk, high bone mineral density, and thicker femoral cortices in narrower bones," the authors conclude.

The authors suggested that apparently "strong" bones of diabetes patients may in fact be fragile because the bones do not repair well. This fragility may be caused by the buildup of microcracks (small cracks) or cortical porosity (the amount of pores, or how much of the bone is actually empty space, in the cortical bone). However, the study's results did not explain the exact cause of increased fracture risk among patients with poorly controlled type 2 diabetes.

The study was published January 11 in Diabetes Care. No funding or conflict of interest information was available. 

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Review Date: 
January 21, 2013