Postmenopausal breast cancer survivors may be at an increased risk for bone fractures, according to a recent study supported in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. While previous studies have found low bone density among postmenopausal women surviving breast cancer and rapid bone loss among those treated with chemotherapy, studies on fracture risk among breast cancer survivors have yielded inconsistent results. This new study by Zhao Chen, Ph.D., M.P.H., of the University of Arizona and her colleagues found a clear link between breast cancer and subsequent bone fractures among postmenopausal women.

Using data from the Women's Health Initiative Observational Study (WHI-OS), Dr. Chen and her team compared fracture rates of nearly 5,300 breast cancer survivors to those of almost 81,000 women with no cancer history. All of the women were postmenopausal and were followed for approximately 5 years. Data analysis revealed that fracture rates of the spine (only among women who had breast cancer diagnosed before age 55), wrist and other (nonhip) skeletal sites were higher among breast cancer survivors, although hip fracture rates were comparable among the two groups of women.

The increased risk for fractures among breast cancer survivors persisted even after data were adjusted for other risk factors, such as fracture history, medication use and lifestyle behaviors. The authors conclude that, pending confirmation by other studies, "the excess number of fractures may be as high as 13,000 per year for the two million postmenopausal breast cancer survivors in the United States."

Osteoporosis is characterized by low bone mass, bone fragility and an increased risk for fracture. The Surgeon General's Report on Osteoporosis and Bone Health (www.surgeongeneral.gov/library/bonehealth/) estimates that 10 million Americans over age 50 have osteoporosis while another 34 million are at risk. Each year an estimated 1.5 million people suffer an osteoporosis-related fracture. Several diseases and medications, including cancer and cancer treatments, have been linked to the development of osteoporosis and fracture.

The purpose of the WHI-OS is to give reliable estimates of risk factors for heart disease, cancers and fractures. The study has enlisted over 93,000 postmenopausal women between the ages of 50 to 79. The health of WHI-OS participants has been tracked over an average of nine years. Women who joined this study fill out periodic health forms and also visit the clinic three years after enrollment. For more information, see www.nhlbi.nih.gov/whi/os.htm.

Information on osteoporosis is available from the NIH Osteoporosis and Related Bone Diseases National Resource Center; phone toll-free 800-624-BONE (2663), or visit www.osteo.org. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22 NIAMS (free call) or visit the NIAMS Web site at www.niams.nih.gov.

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases, the training of basic and clinical scientists to carry out this research, and the dissemination of information on research progress in these diseases.

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Chen Z., et al. Fracture risk among breast cancer survivors. Arch Intern Med 2005;165:552-558.