Vasomotor symptoms and the homeostatic model assessment of insulin-resistance in Korean postmenopausal women

Vasomotor symptoms and their links to cardiovascular disease risk

Hot flashes and night sweats, also known as vasomotor symptoms (VMS), are common and bothersome symptoms of the menopause transition. In addition to negatively impacting quality of life, VMS have been associated with multiple indicators of cardiovascular disease (CVD) risk, including an unfavorable CVD risk factor profile, increased subclinical CVD, and elevated risk of CVD events. Several facets of VMS have been associated with CVD risk, including the frequency, timing, duration, and severity of VMS. VMS may signify poor or degrading cardiovascular health among midlife women and indicate women who warrant focused CVD prevention efforts.

Glutamatergic and GABAergic neurons in the preoptic area of the hypothalamus play key roles in menopausal hot flashes

During menopause, when estrogen levels are low, abnormalities in the hypothalamic preoptic area (POA) of the thermoregulatory center can cause hot flashes. However, the involved neural population has not been identified. Proteomics showed that under low estrogen, differentially expressed proteins in the hypothalamus were associated with glutamatergic and GABAergic synapses. RNAscope, Western blotting and qRT-PCR indicated that the number of glutamatergic neurons in the POA was decreased, while the number of GABAergic neurons was increased. Chemogenetics showed that the rat body temperature decreased slowly after glutamatergic neurons were activated and increased quickly after glutamatergic neurons were inhibited, while it increased quickly after GABAergic neurons were activated and decreased slowly after GABAergic neurons were inhibited. RNAscope, immunofluorescence, Western blotting and qRT-PCR further showed that glutamate decarboxylase (GAD) 1 expression in the POA was increased, while GAD2 expression in the POA was decreased; that thermosensitive transient receptor potential protein (ThermoTRP) M (TRPM) 2 expression in glutamatergic neurons was decreased, while TRPM8 expression in GABAergic neurons was increased; and that estrogen receptor (ER) α and β expression in the POA was decreased, and ERα and ERβ expressed in both glutamatergic and GABAergic neurons. Estrogen therapy corrected these abnormalities. In addition, CUT&Tag and Western blot after injection of agonists and inhibitors of ERs showed that ERα and ERβ were both transcription factors in glutamatergic and GABAergic synapses. Mechanistically, during menopause, estrogen may regulate the transcription and expression of GADs and ThermoTRPs through ERs, impacting the number and function of glutamatergic and GABAergic neurons, resulting in unbalanced heat dissipation and production in the POA and ultimately triggering hot flashes.

Machine Learning Approaches to Identify Factors Associated with Women's Vasomotor Symptoms Using General Hospital Data

BACKGROUND

To analyze the factors associated with women's vasomotor symptoms (VMS) using machine learning.

METHODS

Data on 3,298 women, aged 40-80 years, who attended their general health check-up from January 2010 to December 2012 were obtained from Korea University Anam Hospital in Seoul, Korea. Five machine learning methods were applied and compared for the prediction of VMS, measured by the Menopause Rating Scale. Variable importance, the effect of a variable on model performance, was used for identifying the major factors associated with VMS.

RESULTS

In terms of the mean squared error, the random forest (0.9326) was much better than linear regression (12.4856) and artificial neural networks with one, two, and three hidden layers (1.5576, 1.5184, and 1.5833, respectively). Based on the variable importance from the random forest, the most important factors associated with VMS were age, menopause age, thyroid-stimulating hormone, and monocyte, triglyceride, gamma glutamyl transferase, blood urea nitrogen, cancer antigen 19-9, C-reactive protein, and low-density lipoprotein cholesterol levels. Indeed, the following variables were ranked within the top 20 in terms of variable importance: cancer antigen 125, total cholesterol, insulin, free thyroxine, forced vital capacity, alanine aminotransferase, forced expired volume in 1 second, height, homeostatic model assessment for insulin resistance, and carcinoembryonic antigen.

CONCLUSION

Machine learning provides an invaluable decision support system for the prediction of VMS. For managing VMS, comprehensive consideration is needed regarding thyroid function, lipid profile, liver function, inflammation markers, insulin resistance, monocyte count, cancer antigens, and lung function.

Persistent vasomotor symptoms and breast cancer in the Women's Health Initiative

OBJECTIVE

Vasomotor symptoms (VMS) including hot flashes and night sweats are common during the menopausal transition and may persist. Although VMS pathophysiology is complex, estrogen's efficiency as VMS therapy suggests hormonal environment change may influence this process. As studies of VMS and breast cancer are inconsistent, we examined associations between persistent VMS and breast cancer incidence and mortality.

METHODS

The analytic sample included 25,499 postmenopausal women aged 50 to 79 in the Women's Health Initiative (WHI) without current/former menopausal hormone therapy use with information on VMS status (never vs persistent). Breast cancers were verified by medical record review. Cause of death attribution was enhanced by serial National Death Index queries. Associations between VMS status and breast cancer incidence and mortality was determined using time dependent Cox regression analyses adjusted for breast cancer risk factors.

RESULTS

Through 17.9 years (median) follow-up, 1,399 incident breast cancers were seen. Women with persistent VMS (VMS median duration 10+ years) (n = 9,715), compared to women with never VMS (n = 15,784), had a higher breast cancer incidence (hazard ratio [HR] 1.13 95% confidence interval [CI] 1.02-1.27). While breast cancer-specific mortality was higher in women with persistent VMS (HR 1.33 95% CI 0.88-2.02), the difference was not statistically significant. Persistent VMS status had no influence on breast cancer overall survival (HR 1.02 95% CI 0.81-1.29).

CONCLUSION

Women with persistent VMS are more likely to be diagnosed with breast cancer than women who never experienced VMS, but not more likely to die from breast cancer.

Vasomotor Symptoms: More Than Temporary Menopausal Symptoms

Vasomotor symptoms (VMS), such as hot flashes and night sweating, are classic menopausal symptoms experienced by a majority of perimenopausal and postmenopausal women. VMS have received a great deal of attention due to their relationship with cardiometabolic risk. Further, accumulating evidence indicates that VMS are associated with an increased risk of several chronic diseases, including metabolic syndrome, type 2 diabetes mellitus, nonalcoholic fatty liver diseases, and osteoporosis in perimenopausal and postmenopausal women. These findings suggest VMS as biomarkers of impaired cardiometabolic conditions rather than just temporary symptoms in menopausal women, warranting further studies to confirm the casual relationship of VMS with these diseases and the exact underlying mechanism in this context.

Vasomotor symptom characteristics: are they risk factors for incident diabetes?

OBJECTIVE

Vasomotor symptoms (VMS), encompassing hot flashes and night sweats, may be associated with diabetes, but evidence is limited. We sought to estimate these associations.

METHODS

Among 150,007 postmenopausal Women's Health Initiative participants from 1993 to 2014, we prospectively examined associations of incident diabetes with VMS characteristics at enrollment: any VMS, severity (mild/ moderate/severe), type (hot flashes/night sweats), timing (early [premenopausal or perimenopausal]/late [postmenopausal]), and duration. Cox proportional-hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Mean duration of follow-up was 13.1 years. VMS prevalence was 33%. Reporting any VMS was associated with 18% increased diabetes risk (95% CI 1.14, 1.22), which increased with severity (mild: HR 1.13, 95% CI 1.08, 1.17; moderate: HR 1.29, 95% CI 1.22, 1.36; severe: HR 1.48, 95% CI 1.34, 1.62) and duration (4% per 5 years, 95% CI 1.03, 1.05), independent of obesity. Diabetes risk was more pronounced for women reporting any night sweats (night sweats only: HR 1.20, 95% CI 1.13, 1.26; night sweats and hot flashes: HR 1.22, 95% CI 1.17, 1.27) than only hot flashes (HR 1.08, 95% CI 1.02, 1.15) and was restricted to late VMS (late: HR 1.12, 95% CI 1.07, 1.18; early and late: HR 1.16, 95% CI 1.11, 1.22; early: HR 0.99, 95% CI 0.95, 1.04).

CONCLUSIONS

VMS are associated with elevated diabetes risk, particularly for women reporting night sweats and postmenopausal symptoms. The menopause transition may be an optimal window for clinicians to discuss long-term cardiovascular/metabolic risk with patients and leverage the bother of existing symptoms for behavior change to improve VMS and reduce diabetes risk.

Vasomotor symptoms and metabolic syndrome

A vast majority of menopausal women suffer from vasomotor symptoms, such as hot flushes and night sweats, the mean duration of which may be up to 7-10 years. In addition to a decreased quality of life, vasomotor symptoms may have an impact on overall health. Vasomotor symptoms are associated with overactivity of the sympathetic nervous system, and sympathetic overdrive in turn is associated with metabolic syndrome, which is a known risk factor for cardiovascular disease. Menopausal hot flushes have a complex relationship to different features of the metabolic syndrome and not all data point towards an association between vasomotor symptoms and metabolic syndrome. Thus, it is still unclear whether vasomotor symptoms are an independent risk factor for metabolic syndrome. Research in this area is constantly evolving and we present here the most recent data on the possible association between menopausal vasomotor symptoms and the metabolic syndrome.