Transdermal hormone therapy and bone health

The clinical aftermath of the reporting of the initial findings of the Women’s Health Initiative (WHI) in 2002 was a profound reduction in the use of hormone therapies by menopausal women. This reduction led to a well documented increase in vasomotor symptoms and vaginal atrophy among those women who discontinued their hormone regimens. However, another adverse impact among these women, as well as many other menopausal women, is the well recognized increased likelihood of osteoporosis resulting from the decline in circulating estradiol levels associated with natural and surgical menopause. Although the use of non-hormonal drugs such as bisphosphonates has been shown to reduce the risk of fracture in women with osteoporosis, bisphosphonates have not been shown to reduce the risk of fracture in non-osteoporotic women. Indeed, only oral estrogen (as demonstrated in the WHI studies) has been shown to reduce the risk of fracture in osteoporotic and non-osteoporotic women. As non-oral hormone therapies have been shown to be as effective in treating vasomotor symptoms and vulvovaginal atrophy and to have a different (and perhaps more beneficial) physiological effect than oral regimens, it behooves us to assess the impact of non-oral hormone regimens on bone mineral density and fracture risk. Although there are no clinical trials that primarily assess the impact of non-oral regimens on fracture risk in menopausal women, numerous studies are consistent in demonstrating the positive impact of non-oral regimens in maintaining and increasing bone mineral density among users, even for those women using estrogen doses that are considered to be “too low” to have a beneficial impact on other menopausal symptoms.