Diabetic women need fracture prevention strategy

After 22 years of following women with type 1 or 2 diabetes, researchers detected a statistically significant increased risk of hip fracture, highlighting the need for prevention efforts in this population.

"Increased risk of fracture has not traditionally been considered a consequence of diabetes mellitus," Dr. Mohsen Janghorbani from Isfahan University of Medical Sciences in Iran noted in an email to Reuters Health.

"However, this study, as well as several other observational studies, has demonstrated that individuals with type 1 and type 2 diabetes are at increased risk of hip fracture and fall, despite higher weight than nondiabetic control individuals," the researcher added.

The findings are based on data from 109,983 women aged 34 to 59 years in 1980 who were followed through 2002. As participants in the Nurses' Health Study, the women were asked about their history and treatment of diabetes and other potential risk factors for hip fracture.

During the study period, 1,398 women (1.2 percent) fractured a hip, Janghorbani and colleagues at Harvard University, Boston, note in the July issue of Diabetes Care.

Compared with nondiabetic women, after factoring in the effects of age, the risk of fracture was seven times higher in women with type 1 diabetes and almost twice as high in those with type 2 diabetes, the researchers report.

After further adjusting the data for the effects of weight, smoking, physical activity, menopausal status, postmenopausal hormone use, and daily intake of calcium, vitamin D, and protein, the risk of hip fracture was more than six times higher women with type 1 diabetes and more that two-times higher in women with type 2 diabetes.

The mechanisms involved in these negative effects on fracture risk in diabetes are not entirely clear, the investigators note. The risk of hip fracture increased with longer duration of type 2 diabetes; having type 2 diabetes for 12 or more years was associated with a three-times higher risk of hip fracture, compared with no diabetes.

The risk of hip fracture also increased with insulin treatment. This may indicate a more severe disease process, the team notes, rather than being a direct contributor to hip fracture. On the other hand, insulin may exert negative effects on the bones. The role of insulin in fracture risk is uncertain, they add, and requires more study.

Overall, "the results of this study highlight the need for fracture and fall prevention strategies in patients with diabetes," Janghorbani concluded.

SOURCE: Diabetes Care, July 2006.