Effect of transdermal estrogen therapy on bone mineral density in postmenopausal korean women

Effects of transdermal versus oral hormone replacement therapy in postmenopause: a systematic review

PURPOSE

To summarize available evidence comparing the transdermal and the oral administration routes of hormone replacement therapy (HRT) in postmenopausal women.

METHODS

We performed a systematic review of the literature on multiple databases between January 1990 and December 2021. We included randomized controlled trials and observational studies comparing the transdermal and oral administration routes of estrogens for HRT in postmenopausal women regarding at least one of the outcomes of interest: cardiovascular risk, venous thromboembolism (VTE), lipid metabolism, carbohydrate metabolism, bone mineral density (BMD), and risk of pre-malignant and malignant endometrial lesions, or breast cancer.

RESULTS

The systematic literature search identified a total of 1369 manuscripts, of which 51 were included. Most studies were observational and of good quality, whereas the majority of randomized controlled trials presented a high or medium risk of bias. Oral and transdermal administration routes are similar regarding BMD, glucose metabolism, and lipid profile improvements, as well as do not appear different regarding breast cancer, endometrial disease, and cardiovascular risk. Identified literature provides clear evidence only for the VTE risk, which is higher with the oral administration route.

CONCLUSIONS

Available evidence comparing the transdermal and oral administration routes for HRT is limited and of low quality, recommending further investigations. VTE risk can be considered the clearest and strongest clinical difference between the two administration routes, supporting the transdermal HRT as safer than the oral administration route.

Combined effects of reproductive and hormone factors and obesity on the prevalence of knee osteoarthritis and knee pain among middle-aged or older Chinese women: a cross-sectional study

Background

Knee osteoarthritis (KOA) is one form of degenerative arthritis that results from the breakdown of cartilage and underlying bone. The prevalence of KOA is considerably higher in women than in men; however, the reason for this difference has not been thoroughly elucidated to date. The aim of the present study was to estimate the effects of reproductive and hormone factors and obesity on KOA prevalence among Chinese women.

Methods

The cross-sectional study included 7510 women with a mean age of 62.6 ± 8.6 years. Knee pain was defined as pain or aching stiffness on most days for at least 1 month during the past 12 months or persistent pain or aching stiffness within the past week. Clinical KOA was diagnosed based on both pain complaints and a Kellgren-Lawrence grade ≥ 2 X-ray radiograph of at least one knee.

Results

Oral contraceptives use (OR 1.18, 1.05–1.34), ≥3 pregnancies (1.38, 1.20–1.60), and postmenopausal hormone replacement therapy (HT) (1.59, 1.23–2.06) were positively associated with knee pain, while oral contraceptives use (1.28, 1.04–1.57), and HT (1.79, 1.21–2.65) were positively associated with clinical KOA. Obesity and oral contraceptives use showed additive and multiplicative effects on knee pain. The OR for knee pain among women with a BMI ≥24 kg/m² and oral contraceptives use was 2.00 (1.68–2.38) compared with women with a BMI < 24 kg/m² and no oral contraceptives use.

Conclusions

A high number of pregnancies, oral contraceptives use, and HT are independent risk factors for KOA, and the effects of reproductive and hormone factors on KOA may be increased by obesity.

A summary of the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health

Bone growth, development, and remodeling are modulated by numerous circulating hormones. Throughout the lifespan, the extent to which each of the hormones impacts bone differs. Understanding the independent and combined impact of these hormones on controlling bone remodeling allows for the development of more informed decision making regarding pharmacology, specifically the use of hormonal medication, at all ages. Endocrine control of bone health in women is largely dictated by the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and the hypothalamic-pituitary-ovarian (HPO) axis. Growth hormone, secreted from the pituitary gland, stimulates cells in almost every tissue to secrete IGF-1, although the majority of circulating IGF-1 is produced hepatically. Indeed, systemic IGF-1 concentrations have been found to be correlated with bone mineral density (BMD) in both pre- and post-menopausal women and is often used as a marker of bone formation. Sex steroids produced by the ovaries, namely estradiol, mediate bone resorption through binding to estrogen receptors on osteoclasts and osteoblasts. Specifically, by increasing osteoclast apoptosis and decreasing osteoblast apoptosis, adequate estrogen levels prevent excessive bone resorption, which helps to explain the rapid decline in bone mass that occurs with the menopausal decrease in estrogen production. Though there are documented correlations between endogenous estrogen concentrations and GH/IGF-1 dynamics, this relationship changes across the lifespan as sex-steroid dynamics fluctuate and, possibly, as tissue responsiveness to GH stimulation decreases. Aside from the known role of endogenous sex steroids on bone health, the impact of exogenous estrogen administration is of interest, as exogenous formulations further modulate GH and IGF-1 production. However, the effect and extent of GH and IGF-1 modulation seems to be largely dependent on age at administration and route of administration. Specifically, premenopausal women using combined oral contraceptive therapy (COC), post-menopausal women taking oral hormone therapy (HT), and both pre- and post-menopausal women using a transdermal form of estrogen therapy (COC or HT) demonstrate disparate GH/IGF-1 responses to exogenous estrogen. This review serves to summarize what is currently known regarding the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health.

The Effects of Transdermal Estrogen Delivery on Bone Mineral Density in Postmenopausal Women: A Meta-analysis

Due to its minimal systematic adverse effects, transdermal estrogen is widely used for the prevention of osteoporosis in postmenopausal women. The present meta-analysis aimed to clarify the effects of transdermal estrogen on bone mineral density (BMD) of postmenopausal women. Studies were identified by searching electronic databases including Cochrane Library, MEDLINE, Embase , and CINAHL databases, and also the Sciences Citation Index. Systematic review of articles was published between January 1989 to February 2016.Reference lists of the included articles were also evaluated and consultations were made with relevant experts. While 132 studies included the desired keywords, only nine clinical trials met the inclusion criteria and were finally reviewed. The pooled percent change in BMD was statistically significant in favor of transdermal estrogen. According to resulting pooled estimate, lumbar spine BMD one and two years after transdermal estrogen therapy was respectively 3.4% (95% CI: 1.7-5.1) and 3.7% (95% CI: 1.7-5.7) higher than the baseline values. The test for heterogeneity was not statistically significant based on the I² heterogeneity index. One-two years of transdermal estrogen delivery can effectively increase BMD and protect the bone structure in postmenopausal women.

Effects of Hormone Therapy on Serum Lipid Levels in Postmenopausal Korean Women

Objectives

This study was conducted to examine the effects of hormone therapy on serum lipid levels in postmenopausal Korean women.

Methods

This retrospective cohort study included 154 healthy postmenopausal Korean women. Seventy-nine women took oral estrogen (conjugated equine estrogen 0.625 mg/day or equivalent), and 75 applied estrogen transdermally using 0.1% 17β-estradiol gel. Micronized progesterone (MP) was added to 40 women of oral group and 49 women in transdermal group. Serum levels of triglyceride, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and lipoprotein (a) were measured before, 3 and 6 month after hormone therapy.

Results

At baseline, mean body mass index (BMI) were lower (22.76 vs. 23.74 kg/m²) and proportion of family history of cardiovascular disease (CVD) (61 vs. 39%) were higher in oral group. In oral group, LDL-C and lipoprotein(a) levels decreased, and triglyceride and HDL-C levels increased significantly after 3 and 6 months. There was no significant change in lipoprotein levels compared to the baseline in transdermal group. There were also no differences with additional MP. Changing pattern of HDL-C during 6 months was significantly different by the route of estrogen administration.

Conclusion

Oral estrogen therapy might be more beneficial than transdermal estrogen in terms of lipid in postmenopausal Korean women. The estrogen effects are not influenced by adding MP.