According to recent research published in the Hypertension journal, women over the age of 45 who take estrogen hormone therapy orally are more prone to developing high blood pressure compared to those using transdermal or vaginal forms of therapy. The study specifically focused on postmenopausal women who were undergoing estrogen-only hormone therapy.
The study, which involved over 100,000 women aged 45 and older, revealed that the ingestion of estrogen in pill form may heighten the risk of high blood pressure, while transdermal and vaginal applications showed lower associated risks. More precisely, oral estrogen was found to carry a 14% higher risk of high blood pressure compared to transdermal estrogen creams, and a 19% greater risk when compared to vaginal estrogen creams or suppositories. The study also highlighted that the use of non-oral estradiol, a synthetic form of estrogen, at the lowest dose and for the shortest duration, was associated with the lowest risk of developing high blood pressure.
The findings from the study, published in the peer-reviewed journal Hypertension, emphasized that women aged 45 years and older who opt for oral estrogen hormone therapy are at a higher risk of developing high blood pressure than those who choose transdermal or vaginal formulations. This research adds to the existing body of knowledge that suggests women experience decreased production of estrogen and progesterone after menopause, potentially increasing their susceptibility to cardiovascular diseases, including heart failure.
Hormone therapy is commonly prescribed to alleviate menopause symptoms, aid gender-affirming care, and serve as a form of contraception. Previous studies have suggested that certain hormone therapies may reduce the risk of cardiovascular diseases in menopausal women under 60 years of age or within 10 years of menopause. However, the effects of different types of hormone therapy on blood pressure in menopausal women have remained uncertain.
Lead author Cindy Kalenga, an M.D./Ph.D. candidate at the University of Calgary, explained that orally ingested estrogens are metabolized in the liver, leading to increased factors that contribute to higher blood pressure. Kalenga further noted that postmenopausal women face an elevated risk of high blood pressure compared to premenopausal women, and previous studies have associated specific hormone therapies with higher rates of heart disease. Therefore, the research team sought to delve deeper into factors related to hormone therapy, such as the route of administration (oral vs. non-oral) and the type of estrogen used, to investigate their potential effects on blood pressure.
The study encompassed a significant cohort of over 112,000 women aged 45 years and older who had filled at least two consecutive prescriptions for estrogen-only hormone therapy in Alberta, Canada, between 2008 and 2019. The researchers identified the occurrence of high blood pressure (hypertension) through health records.
The researchers primarily examined the association between the route of estrogen-only hormone therapy administration and the risk of developing high blood pressure at least one year after starting treatment. They evaluated three different routes: oral (by mouth), transdermal (topical, applied to the skin), and vaginal application. Additionally, the study analyzed the formulation of estrogen used and its impact on the risk of high blood pressure. The medical records of individuals taking estrogen-only hormone therapy were reviewed, and the two most common forms of estrogen used by the participants were estradiol (a synthetic form of estrogen that closely mimics the body’s natural production in premenopausal years) and conjugated equine estrogen (an animal-derived form of estrogen and the oldest type of estrogen therapy).
Key findings from the analysis include:
- Women taking oral estrogen therapy had a 14% higher risk of developing high blood pressure compared to those using transdermal estrogen and a 19% higher risk compared to those using vaginal estrogen creams or suppositories. When accounting for age, a stronger association was observed among women younger than 70 years of age compared to women older than 70.
- Conjugated equine estrogen was associated with an 8% increased risk of developing high blood pressure compared to estradiol.
The study also noted that the duration of estrogen use and the dosage were directly correlated with a higher risk of high blood pressure. Kalenga emphasized that these findings suggest that menopausal women considering hormone therapy should be informed about different estrogen options that carry lower cardiovascular risks. Low-dose, non-oral estrogens, such as transdermal or vaginal forms of estradiol, for the shortest feasible duration, should be considered based on individual symptoms and the risk-benefit ratio. However, this must be balanced with the significant benefits of hormone therapy, which include the treatment of common menopausal symptoms.
On a global scale, the average age of natural menopause for women is around 50 years. Current evidence supports the initiation of menopausal hormone therapy in the early stages for potential cardiovascular benefits, but not in the late stages of menopause, as outlined in the American Heart Association’s 2020 Statement on Menopause Transition and Cardiovascular Disease Risk: Implications for Timing of Early Prevention. Previous studies have also suggested that menopausal hormone therapy can alleviate menopause symptoms, such as hot flashes, night sweats, mood changes, and sleep disturbances.
Sofia B. Ahmed, M.D., M.M.Sc., a professor of medicine at the University of Calgary, emphasized the significance of understanding safe and effective hormonal treatments for women during menopause. Ahmed stressed the importance of an individualized decision-making process that involves open dialogue with healthcare professionals. The researchers plan to conduct further investigations into combined estrogen and progestin therapies, as well as progestin-only formulations, to examine their impact on heart and kidney diseases.
It is important to note that the study had some limitations. The findings regarding the impact of different forms of hormone therapy on high blood pressure were solely based on medical records. The study excluded women younger than 45 years of age and did not collect data on hysterectomies or menopausal status. However, initiation of estrogen therapy in women aged 45 and above was used as an indicator of postmenopausal status. The study specifically focused on estrogen-only therapy, which is primarily prescribed for women who have undergone a hysterectomy, whereas women with an intact uterus may receive a combination of estrogen and progestin. Therefore, the study’s findings can only be applied to women undergoing estrogen-only hormone therapy. Furthermore, the research was conducted in Canada, which may introduce regional differences. However, Canadian guidelines align with U.S. guidelines from the American College of Obstetricians and Gynecologists, both of which recommend hormone therapy in women with appropriate indications while cautioning against considering it as a preventive measure or treatment for hypertension or heart disease.
The authors of the study, funded by the Canadian Institutes of Health Research, acknowledge the need for further large-scale randomized studies that encompass the complexities of hormone therapy during the crucial transition period of menopause. They believe that providing individuals going through menopause with accurate information about the most effective and safe hormonal treatments is essential, considering the significant impact menopause has on quality of life, economic factors, work productivity, and social relationships.
Reference:
Title: Oral Estrogen Hormone Therapy’s Troubling Tie to High Blood Pressure
Date: June 5, 2023
Journal: Hypertension
DOI: 10.1161/HYPERTENSIONAHA.122.19938
Co-authors: Amy Metcalfe, Ph.D.; Magali Robert, M.D., M.Sc.; Kara Nerenberg, M.D., M.Sc.; Jennifer MacRae, M.D., M.Sc.
Table of Contents
Frequently Asked Questions (FAQs) about Hormone therapy and high blood pressure risk
What does the study reveal about the association between hormone therapy and high blood pressure?
The study reveals that women over the age of 45 who take estrogen hormone therapy orally are more likely to develop high blood pressure compared to those using transdermal or vaginal forms of therapy. The risk of high blood pressure was found to be higher with oral estrogen, emphasizing the importance of considering alternative options.
Does the type of estrogen used in hormone therapy make a difference?
Yes, the study found that the type of estrogen used can impact the risk of high blood pressure. Synthetic forms of estrogen, such as estradiol, were associated with lower risks compared to animal-derived estrogen, like conjugated equine estrogen. This suggests that the choice of estrogen type can influence cardiovascular outcomes.
Are there specific routes of hormone therapy administration that are safer for blood pressure?
The study highlights that transdermal and vaginal forms of hormone therapy appear to be associated with lower risks of high blood pressure compared to oral administration. Women considering hormone therapy should discuss these different routes with their healthcare providers to make an informed decision based on individual symptoms and the risk-benefit ratio.
What are the implications of these findings for menopausal women?
These findings provide valuable insights for menopausal women considering hormone therapy. It is important to weigh the potential cardiovascular risks, such as high blood pressure, when choosing the type and route of hormone therapy. Low-dose, non-oral estrogens, like transdermal or vaginal forms of estradiol, used for the shortest duration necessary, may be associated with the lowest risk of high blood pressure.
Are there any limitations to the study?
Yes, the study has a few limitations. It primarily focused on estrogen-only hormone therapy and did not include women younger than 45 years of age. The findings may not apply to women who have an intact uterus or experience premature or early menopause. Additionally, the study relied on medical records and did not collect data on hysterectomies or menopausal status, using age as an indicator of postmenopausal status.
What is the recommendation for women considering hormone therapy?
Women considering hormone therapy should have open discussions with their healthcare providers. The study suggests that if hormone therapy is necessary, considering lower-risk options, such as non-oral estrogen in transdermal or vaginal forms, for the shortest duration based on individual symptoms, may be prudent. However, the benefits and risks of hormone therapy should be carefully evaluated on a case-by-case basis.
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