Bone Abstracts

Numerous studies in adult patients with type 1 diabetes (T1D) described an association with reduced bone mineral density, altered bone geometry and osteoporosis. Epidemiologic data on hip fractures demonstrate an increased risk in a large adult population with T1D. Diabetes is therefore categorized as adversely affecting the skeleton.

In children and adolescence observations have been more controversial regarding bone mineral content, bone mineral density and markers of bone turn-over. Several studies have documented a lower bone mineral density (BMD) or bone mass, altered bone strength and postponed attainment of peak bone mass. However, other studies found normal levels of bone mass and BMD. The methods used for measuring bone quality have varied making comparison of results from individual studies difficult. The majority of studies are cross-sectional using dual-energy X-ray absorptiometry (DXA) of the spine. The clinical impact of possibly lower bone mineralization in children with T1D has to be discussed since fracture rate data are lacking. Analyzing bone histomorphometry and micro CT in young adults with T1D normal results were seen. However, with diabetes associated complications lower bone mass was present.

Low rates of bone formation along with reduced trabecular bone structure and strength have been shown in rat and mice models of T1D but it is unclear whether this could be transferred to humans. The mechanisms behind impaired bone metabolism in T1D are not clear. Lack of insulin, IGF1 and further osteoanabolic factors (e.g. amylin), chronic hyperglycemia, inflammation and increased concentrations of advanced glycation end products (AGE) as well as diabetic complications like microangiopathy or neuropathy were reported. Further a smaller muscle mass and an intrinsic bone disease were discussed.

The extent of diagnostic and therapeutic activities in patients with T1D in respect to generalized bone disease or diabetic osteopenia should be based on individual conditions and risk profile. Encouraging patients to optimize glycemic control in the long run, to follow a healthy life style and to increase muscle mass by emphasizing physical activity may help to prevent the reported decrease of bone mass and elevated fracture risk later in the course of the disease.