Before the Women’s Health Initiative was published in July 2002, more than 11 million post-menopausal women in the United States relied on hormone therapy (HT), but now a substantial proportion of these women have stopped this therapy. HT increases and maintains bone mass and reduces the incidence of fractures. Bone loss and fracture rates are believed to accelerate rapidly on discontinuation of HT. Yates and colleagues used data from a longitudinal study started in 1997 to study hip fracture rates after discontinuation of HT.

They studied postmenopausal women 50 years and older who had no history of osteoporosis or use of osteoporosis-specific therapies other than HT. More than 200,000 women were recruited by 4,236 primary care physicians throughout the United States. Extensive medical and personal data were collected from each participant as part of intake assessment that included bone mineral density measurement. Approximately one year later, data were collected again, but this questionnaire included information on any new fractures. Women with four or more fractures during the year were excluded because these were believed to represent traumatic rather than osteoporotic fractures.

Data were available for 140,584 women. The majority (92 percent) of the women were white, and the mean age and body mass index (BMI) were 63.8 years and 27.7 kg per m2, respectively. The average bone mineral density T score was −0.82. About one half of the women smoked, and about one in four women reported that her mother had incurred a fracture. Overall, 48 percent were using HT at the beginning of the study, and 14 percent reported prior use.

Analysis of the data gathered at the beginning of the study showed significant associations between duration and recency of HT and the T score, BMI, health status, previous fracture, maternal fracture history, and steroid use. During the study, 269 women reported a new hip fracture. The rate of new hip fractures was similar in women who had discontinued HT and in those who had never used the therapy. The unadjusted rate for women who had never used or had discontinued HT was approximately three times that for current HT users. After adjustment for age, BMI, previous fracture, health status, maternal fracture, and steroid use, the rate of hip fracture in current HT users remained significantly lower—about 40 percent lower than in women who had never used HT. Hip fracture rates were highest in women who had discontinued HT within five years, but the fracture risk was not related to duration of therapy.

The authors conclude that the protective effects of HT against hip fracture are lost rapidly when therapy is discontinued and that recent discontinuation of HT may place a postmenopausal woman at increased risk of hip fracture.

editor’s note: While the lay and medical press continue to emphasize the potential adverse effects of HT, this study reminds us of its substantial benefits. Ideally, the decision to use HT is a carefully considered individual choice made by a well-informed woman. Unfortunately, millions of women have discontinued HT without physician consultation, thus missing the opportunity to benefit from an alternative preventive regimen for osteoporosis. Family physicians are in a position to prevent a potential epidemic of osteoporosis-related pathology in baby boomers, which could overwhelm families and health and social services. This epidemic could be fueled from two sources—women entering menopause who are not getting bone-preserving treatments and women already in menopause who are losing protection as they discontinue HT.—a.d.w.