Menopause hormone therapy (MHT) did not alter thyroid function in postmenopausal women with euthyroid or subclinical hypothyroidism and improved lipid and glucose parameters in euthyroid postmenopausal women, according to study results published in BMC Endocrine Disorders.
Researchers conducted a retrospective study at a menopause clinic in China to compare the endocrine and metabolic indicators in postmenopausal women before and after MHT. Study authors constructed a database where they collected baseline information and list of medical treatments for 3108 patients receiving MHT at the menopause clinic in Women’s Hospital, Zhejiang University, School of Medicine, between January 2010 and December 2020. The researchers also set up a self-developed MHT record management system where follow-up records were collected and preserved.
Prior to MHT therapy, there were no significant differences in the baseline characteristics (age, age of amenorrhea, time since amenorrhea, age of menarche, residence, educational level, weight, height, BMI, status, waist circumference, hip circumference, waist to hip ratio, and blood pressure readings) of study participants. Patients received a continuous oral MHT regimen with equivalent potencies of estradiol for 6-18 month cycles. Unless the participant had a history of hysterectomy, they were given combined estrogen-progesterone for endometrial protection; patients with hysterectomy were given estrogen alone.
After implementing inclusion and exclusion criteria, the final study population consisted of 587 postmenopausal women with a median age of 52 years (25-75th percentile, 49-54) and a median menopause age of 48 years (25-75th percentile, 45-51).
Enrolled patients were split into 3 groups:
- Group I: euthyroid patients with a low normal TSH range (0.3≤TSH≤2.5 mIU/L, n=460);
- Group II: euthyroid patients with an upper normal TSH range (2.5<TSH≤4.5 mIU/L, n=106);
- Group III: patients with mild subclinical hypothyroidism (4.5<TSH <10 mIU/L, n=21).
The researchers measured the following endocrine indicators: follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), thyroid-stimulating hormone (TSH), free tri-iodothyronine (fT3), and free thyroxine (fT4). They also measured the following lipid and metabolic parameters: triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), and fasting insulin (FINS). Insulin resistance was evaluated with a homeostasis model assessment of insulin resistance (HOMA-IR).
In the final analysis, researchers found that serum FSH levels decreased significantly and serum E2 levels increased significantly in all participants across the study groups. In addition, there was a statistical decrease in serum LH levels in patients in Groups I and II. In Group I, TSH levels increased while fT3 and fT4 levels decreased significantly. In Group II, the serum TSH level decreased with no significant change in fT3 and fT4 levels. In Group III, MHT significantly reduced fT3 levels with no significant difference observed in TSH and fT4 levels. Despite these changes, all thyroid hormone indicators remained within normal limits across all groups.
In patients in Group I, menopause hormone therapy significantly improved lipid parameters, including decreased FPG, FINS, and HOMA-IR. FPG decreased from 5.26 to 5.09, while FINS decreased from 5.40 to 4.80, and HOMA-IR decreased from 1.33 to 1.08. In Groups I and II, TG and TC levels demonstrated a significant decline; there were no observed changes in HDL-C and LDL-C levels. In Groups II and III, FPG, FINS, and HOMA-IR concentrations did not change significantly.
Because this is a retrospective analysis, one study limitation is lack of a control group; additionally, the sample size of patients with mild subclinical hypothyroidism (Group III) was too small, restricting the study’s generalizability. Finally, the researchers reported a selection and recall bias in the recruitment process of study participants.
However, despite these limitations, the researchers concluded that “MHT can effectively regulate reproductive hormone levels and does not affect thyroid function in euthyroid and mild subclinical hypothyroidism postmenopausal women.”
Xu W, Huang Y, Ma L, et al. Clinical observation of menopause hormone therapy in postmenopausal women with euthyroid and mild subclinical hypothyroidism. BMC Endocr Disord. 2023;23:21. doi:10.1186/s12902-023-01269-7