Aims/hypothesis: To study if people with Type I (insulin-dependent) or Type II (non-insulin-dependent) diabetes mellitus have increased risk of hip fracture.
Methods: The study population consisted of 35,444 people 50 years of age and older, attending a health screening in a Norwegian county. They were followed up with respect to hip fracture for 9 years, and 1643 new hip fractures were recorded.
Results: The relative risk of hip fracture for women with Type I diabetes compared with women without diabetes was 6.9 (95% confidence interval 2.2-21.6) adjusted for age, body mass index and daily smoking. The relative risk for men was nearly the same, but not statistically significant. Among women 50-74 years of age with Type II diabetes for more than 5 years, the relative risk was 1.8 (95% confidence interval 1.1-2.9). This increased risk persisted when insulin-treated women were excluded from the analysis. After additional adjustment for possible medical consequences of diabetes (impaired vision, impaired motor abilities and history of stroke) the relative risk among women 50-75 years of age with Type II diabetes was reduced to 1.5 (95% confidence interval 0.9-2.5).
Conclusion/interpretation: We found an increased risk of hip fracture in women younger than 75 years with Type I diabetes or with Type II diabetes of long duration. In older men, there was an increased risk associated with Type II diabetes of shorter duration. Whether the increased risk is attributed to reduced bone mass or to factors associated with falling has not been determined.