A variety of estrogen products are available for use as hormone replacement therapy (HRT), and thy have different chemical structures. All of them can treat symptoms of menopause such as hot flashes and vaginal dryness. The majority of studies are based on conjugated equine estrogens (Premarin); however, a new study evaluated the health benefits of estradiol.
Many women are not aware that Premarin is an acronym for pregnant mares urine. The medication is extracted and purified from the urine and include a variety of estrogens, including a small amount of estradiol. Estradiol is the predominant female sex hormone and is synthesized in the body; it can also be synthesized in the laboratory for preparations including tablets, injection, and skin patches.
The study authors note that estradiol-based regimens have a different risk-benefit profile than conjugated equine estrogens. Therefore, they assessed the risk of death caused by coronary heart disease, stroke, or any disease among users of estradiol-based hormone therapy regimens in a nationwide study in Finland.
The study group comprised 489,105 women who used HRT from 1994 through 2009 (3.3 million HRT exposure years). The data was derived from the nationwide reimbursement register and the national Cause of Death Register. A total of 28,734 HRT users died during the follow-up period; among the deaths, 3,843 were caused by coronary heart disease and 2,464 were caused by stroke. The mortality risk of HRT users with varying duration of exposure (less than 1 year, 1 to 3 years, 3 to 5 years, 5 to 10 years, or more than 10 years) was compared with that in an age-matched background population.
The investigators found that the risk of coronary heart disease was significantly reduced by 18% to 54% in HRT users and positively correlated to duration of HRT exposure. The risk of death from stroke was also reduced by 18% to 39%; however, this reduction was not clearly related to HRT exposure duration. Risk of all-cause mortality (death from any cause) was also reduced in HRT users by 12% to 38%; the longer the duration of HRT exposure, the greater the decrease in mortality. All these risk reductions were comparable in women initiating HRT before age 60 years and women initiating HRT at age 60 years or older.
