Warfarin Use and Risk for Osteoporosis in Elderly Women

doi:10.1059/0003-4819-128-10-199805150-00006

Warfarin Use and Risk for Osteoporosis in Elderly Women

For the Study of Osteoporotic Fractures Research Group* From University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, California. *For members of the Study of Osteoporotic Fractures Research Group, see Ann Intern Med. 1996; 124:187-96. Acknowledgments: The authors thank Dr. Ahmed Bayoumi for helpful comments on earlier versions of this paper. Grant Support: By grants AG05407, AR35582, AG05394, AM35584, AR35583, and NS36016 from the National Institutes of Health, Public Health Service. Requests for Reprints: Sophie A. Jamal, MD, Prevention Sciences Group, Suite 512, 74 New Montgomery Street, San Francisco, CA 94105; e-mail sophie_jamal@quickmail.ucsf.edu. Current Author Addresses: Dr. Jamal: Suite 512, 74 New Montgomery Street, San Francisco, CA 94105.

Abstract

Background: Vitamin K deficiency may be associated with osteoporosis.

Objective: To assess the effects of warfarin on bone.

Design: Prospective observational study.

Setting: Four centers in the United States.

Participants: 6201 elderly, postmenopausal women.

Measurements: Self-reported warfarin use, bone mineral density at the hip and the heel, hip bone loss over 2 years, and fractures during 3.5 years of follow-up. Analyses were adjusted for baseline differences, age, weight, and estrogen use.

Results: Compared with warfarin nonusers (n = 6052), warfarin users (n = 149) more frequently had poor health, involuntary weight loss, nonthiazide diuretic use, and frailty but had similar bone mineral density at the hip (difference, 1.6% [95% CI, −0.7% to 4.1%]) and heel (difference, 2.1% [CI, −1.6% to 5.6%]). Users and nonusers had similar rates of bone loss (1.1% and 0.8%; P = 0.18) and fractures (relative hazard, 1.0 [CI, 0.60 to 1.7]).

Conclusion: In this population, warfarin use did not decrease bone mineral density or increase fracture rates.