β-Cell function in postmenopausal women with isolated post-challenge hyperglycemia

Association between Menopause, Postmenopausal Hormone Therapy and Metabolic Syndrome

(1) Background: We aimed to explore the associations between menopause, postmenopausal hormone therapy, and metabolic syndrome in a large community-based group of Asian women. (2) Methods: This is a cross-sectional study in which we enrolled women aged 30 to 70 years with sufficient information about menopausal status from the Taiwan Biobank. The definition for metabolic syndrome used in this study aligns with the Bureau of Health Promotion's (Taiwan) proposed definition. (3) Results: A total of 17,460 women were recruited. The postmenopausal group had a higher metabolic syndrome prevalence (30% vs. 14%) and 1.17 times higher odds ratio (OR) than the premenopausal group (95% confidence interval [CI] = 1.02 to 1.33). Regarding the types of menopause, surgical menopause was associated with metabolic syndrome (OR = 1.40; 95% CI = 1.20 to 1.63); however, natural menopause was not associated with metabolic syndrome. Interestingly, postmenopausal hormone therapy was associated with a lower risk of metabolic syndrome in the women with natural menopause (OR = 0.79; 95% CI = 0.70 to 0.89), but not in those with surgical menopause. (4) Conclusions: Our results suggest that menopause is associated with an increased prevalence of metabolic syndrome, while postmenopausal hormone therapy is associated with a lower prevalence of metabolic syndrome in women with natural menopause.

Age-related adiposity and beta-cell function: impact on prediabetes and diabetes prevalence in middle-aged and older Han Chinese adults

PURPOSE

To investigate the effect of aging on the prevalence of prediabetes and diabetes, and the influence of aging on the associations among adipose mass, redistribution, β cell function, and the prevalence of hyperglycaemia.

METHOD

This urban-based cross-sectional study included 1033 Chinese Han people, aged 40-65 years. The abdominal subcutaneous fat area (SFA) and visceral fat area (VFA) were determined by magnetic resonance imaging. The prevalence rates of prediabetes and diabetes were analyzed according to age group (40-49, 50-59, and 60-65 years). The effects of aging on abdominal fat mass, adipose distribution, insulin action indexes were also assessed.

RESULTS

Prediabetes and diabetes prevalence gradually increased with age. Both SFA and VFA increased, while SFA/VFA decreased, in the 50-59 and 60-65 years age groups compared to the 40-49 years group. Homeostatic model assessment of insulin resistance (HOMA-IR) increased with fat mass. Homeostatic model assessment of beta-cell function (HOMA-β) and early-phase insulin secretion (∆I30/∆G30) were decreased in the 60-65 years group compared to the younger age groups. Increased age, VFA, and HOMA-IR, as well as decreased HOMA-β, were risk factors for the development of prediabetes and diabetes. The associations between central obesity and the development of prediabetes and diabetes, but not the associations of SFA/VFA, HOMA-IR, and HOMA-β with hyperglycaemia prevalence, weakened with age.

CONCLUSIONS

The prevalence of prediabetes and diabetes increased with age. Central obesity may be related stronger to the development of hyperglycaemia in younger people.

Prolonged bisphenol-A exposure decreases endocrine pancreatic proliferation in response to obesogenic diet in ovariectomized mice

Research on the deleterious actions of bisphenol (BP)-A have focused on its effects on insulin secretion during pre/perinatal periods or adulthood. Estrogens also modulate endocrine pancreas physiology in females during aging; however, the effects of BPA on islet morphophysiology after menopause have not been investigated. We evaluated the effects of BPA exposure on glucose homeostasis and islet morphofunction in ovariectomized (OVX) mice fed on a high-fat diet (HFD). Adult Swiss female mice were underwent to bilateral ovariectomy, and with the confirmation of the establishment of surgical menopause, the females were then submitted, or not,to a normolipidic diet or HFD [control (CTL) and HFD groups, respectively] without or with 1 μg/mL BPA in their drinking water (CBPA and HBPA groups) for 90 days. HFD females displayed obesity, hyperglycemia, hyperinsulinemia, glucose intolerance and insulin resistance. BPA did not modulate HFD-induced obesity or body glucose impairments in HBPA females, and islets isolated from both the HFD and HBPA groups exhibited insulin hypersecretion. The HBPA islets, however, displayed enlarged islet cells and reduced proliferation, in association with the downregulation of mRNAs encoding PDX-1, NGN3 and CCND2 and upregulation of mRNAs encoding ER-β, GPR30, TNF-α and IL-1β in HBPA islets. BPA consumption in OVX mice impaired the islet-cell hyperplasia response to the HFD, partly mediated by increased expression of ER-β and GPR30, which impaired the expression of major genes involved in islet-cell survival and functionality. Together with higher pro-inflammatory cytokines expression in the islet milieu, these alterations may accelerate β-cell failure in postmenopause.