Janghorbani M, Feskanich D, Willett WC, Hu F.

Prospective study of diabetes and risk of hip fracture: the Nurses' Health Study

OBJECTIVE: The purpose of this study was to determine whether women with type 1 and type 2 diabetes are at higher risk of hip fractures. RESEARCH DESIGN AND METHODS: A total of 109,983 women aged 34-59 years in 1980 were followed through 2002 for the occurrence of hip fracture. At baseline and through biennial follow-up, women were asked about their history and treatment of diabetes and other potential risk factors for hip fracture. RESULTS: During 2.22 million person-years of follow-up, 1,398 women had a hip fracture. Compared with women without diabetes, the age-adjusted relative risk (RRs) of hip fracture was 7.1 (95% CI 4.4-11.4) for women with type 1 diabetes and 1.7 (1.4-2.0) for those with type 2 diabetes. After further adjustment for BMI, smoking, physical activity, menopausal status, daily intake of calcium, vitamin D, protein, and postmenopausal hormone use, the multivariate RR of incident hip fracture in individuals with type 1 diabetes compared with individuals without diabetes was 6.4 (3.9-10.3) and with type 2 diabetes was 2.2 (1.8-2.7). The RRs increased with longer duration of type 2 diabetes (3.1 [2.3-4.0] for >or=12 years compared with no diabetes, P for trend < 0.001) and ever use of insulin. CONCLUSIONS: These data indicate that both type 1 and type 2 diabetes are associated with an increased risk of hip fracture. The results of this study highlight the need for fracture-prevention strategies in women with diabetes.