Diabetes and risk of fracture - The Blue Mountains Eye Study

OBJECTIVE - To examine associations between measures of diabetes and risk of fracture in a population-based sample of older Australians. RESEARCH DESIGN AND METHODS - This was a prospective study of 3,654 subjects aged 49 years and older who were residents in the Blue Mountains, west of Sydney, Australia. At baseline, subjects were asked questions about history and treatment of diabetes, and fasting blood samples were taken. Photographs were taken of the retina and lens to grade retinopathy and cataract. Details of fractures (excluding rib and vertebral fractures) were collected by a combination of self-report and medical record searches; all fractures were radiologically confirmed. RESULTS - After 2 years of follow-up, we found that several diabetes-related factors were significantly associated (in multivariate models) with increased risk of all fractures combined, including presence of diabetic retinopathy (adjusted RR 5.4, 95% CI 2.7-10.8), diabetes duration greater than or equal to 10 years (3.3, 1.3-8.2), cortical cataract involving greater than or equal to 25% of the lens area (2.5, 1.3-4.7), and insulin treatment (5.9, 2.6-13.5). The proximal humerus was the only individual fracture site associated with diabetes. Diabetic retinopathy (10.3, 2.2-48.0), diabetes duration (for greater than or equal to 10 years duration; 11.4, 2.4-54.2), and insulin treatment(18.8, 4.0-88.7) were all associated with proximal humerus fracture. CONCLUSIONS - These data suggest a significantly increased risk of fracture associated with diabetic retinopathy, advanced cortical cataract, longer diabetes duration, and insulin treatment. However, there are some shortcomings in this study that may limit these findings.