Relative fracture risk in patients with diabetes mellitus, and the impact of insulin and oral antidiabetic medication on relative fracture risk

Aims/hypothesis We studied the association between fractures and type 1 and type 2 diabetes mellitus.Methods In this case-control study, all subjects diagnosed with a fracture (n=124,655) in Denmark served as cases, and for each case three control subjects (n=373,962) matched for sex and age were retrieved from the general population.Results Type 1 and type 2 diabetes were associated with an increased risk (1) of any fracture (odds ratio OR]=1.3, 95% CI: 1.2–1.5 for type 1 diabetes and 1.2, 95% CI: 1.1–1.3 for type 2 diabetes after adjustment for confounders) and (2) of hip fractures (OR=1.7, 95% CI: 1.3–2.2 for type 1 diabetes, and 1.4, 95% CI: 1.2–1.6 for type 2 diabetes). Furthermore, type 2 diabetes was associated with a significant increase in forearm fractures (OR=1.2, 95% CI: 1.0–1.5), and type 1 diabetes was associated with an increased risk of spine fractures (OR=2.5, 95% CI: 1.3–4.6), whereas type 2 diabetes was not. Use of metformin and sulphonylureas was associated with a significantly decreased risk of any fracture, whereas a non-significant trend towards decreased risk of any fracture was associated with the use of insulin. Except for a decrease in hip fractures with use of sulphonylureas, no change in fracture risk in the hip, spine or forearm was associated with the use of insulin or oral antidiabetic drugs.Conclusions/interpretation Type 1 and type 2 diabetes are associated with an increased risk of any fracture and hip fractures. The use of drugs to control diabetes may reduce the association between diabetes and fractures.