Gonadal hormonal factors before menopause and incident type 2 diabetes in women: A 22-year follow-up of 83 799 women from the E3N cohort study

The Effect of the Oral Contraceptive Pill on Acute Glycaemic Response to an Oral Glucose Bolus in Healthy Young Women: A Randomised Crossover Study

Background/Objective: The oral contraceptive pill (OCP) is widely used by women worldwide, yet the influence of the OCP on carbohydrate metabolism remains under-investigated, with existing studies being few and largely cross-sectional. The study objective was to assess, for the first time, the effect of the combined OCP on postprandial glycaemic response to an oral glucose bolus, using a randomised crossover design. Methods: The effect of a combined monophasic OCP phase on glucose homeostasis and metabolic profile was investigated in 21 healthy young women, who were regular users of either androgenic or anti-androgenic OCP formulations. Plasma glycaemic markers (glucose, insulin and C-peptide) were assessed prior to a 60 g glucose drink (fasting) and for a further 4 h postprandially; once during the "active" (hormone-containing) pill phase and once during the "inactive" (hormone-free) pill phase of the OCP usage cycle. Results: Despite no change in fasting values, in androgenic pill users, postprandial glucose and insulin responses to an oral glucose bolus were ~100% and ~50% greater, respectively, during the active versus inactive phase. In contrast, in anti-androgenic pill users there was no significant change in response between the two OCP usage cycle phases. Conclusions: These findings highlight an acute, but potentially detrimental, influence of the combined OCP on glucose homeostasis, particularly in users of formulations containing androgenic progestogens. Given the high global prevalence of OCP use and increasingly common prolonged active pill regimens, which may continue for months, years or even decades, potential cumulative effects of such changes on metabolic risk demand further investigation.

Menopausal Hormone Therapy in Women with Type 2 Diabetes Mellitus: An Updated Review

Menopause is accompanied by several metabolic adaptations, which are related to insulin resistance, increased total body fat mass, and central abdominal fat accumulation, predisposing women to type 2 diabetes mellitus (T2DM) development. Metabolic syndrome has a high prevalence in postmenopausal women, indicating the loss of estrogen protection on metabolic and cardiovascular health. Moreover, earlier age at menopause has been related to increased risk of T2DM. Menopausal hormone therapy (MHT) has favorable results in glucose metabolism. Indeed, it reduces the risk of T2DM in women without this condition and improves glycemic control in women with T2DM. Before MHT initiation in women with clinical indications, it is imperative to assess their cardiovascular disease (CVD) risk, using official electronic algorithms for score calculation. The latter will determine regimen, dose, and administration route of MHT. Oral estrogens are preferable in women with low CVD risk, while transdermal administration is indicated in those with moderate and high CVD risk, as the risk of stroke and venous thromboembolism (VTE) is increased with oral administration. Oral 17β-estradiol is usually preferred in women with T2DM, as this route has more beneficial effects on glucose metabolism. Oral estrogens are also suggested in perimenopausal or recently postmenopausal women with low CVD risk. Although oral estrogens have favorable effects when indicated, the risk of VTE or stroke should always be considered. Micronized progesterone, dydrogesterone, and transdermal norethisterone are the progestogens used in postmenopausal women with T2DM and intact uterus. MHT should not be initiated in women > 60 years or > 10 years in menopause, as there is an increased thromboembolic risk in women with established atherosclerosis and no additional cardiovascular benefit in women without atherosclerosis. In conclusion, MHT administration in postmenopausal women with T2DM can be safe and effective as long as the therapeutic regimen has been properly selected according to their cardiovascular, metabolic, and fracture risk.

Combined Therapy with Anthracyclines and GnRH Analogues for Breast Cancer: Impact on Ischemic Heart Disease

The combination of classic chemotherapy agents like anthracyclines with novel targeted medications has had a positive impact on women's survival from breast cancer. GnRH analogues are primarily employed to temporarily suppress ovarian function in premenopausal women with hormone-receptor-positive (HR+) breast cancer. Despite their benefits, the true degree of their collateral effects has been widely understudied, especially when it comes to ischemic heart disease. This review aims at summarizing the current state of the art on this issue, with particular focus on the risk for cardiotoxicity associated with the combined use of GnRH analogues and anthracyclines.

Review of mendelian randomization studies on age at natural menopause

Menopause marks the end of the reproductive phase of life. Based on epidemiological studies, abnormal age at natural menopause (ANM) is thought to contribute to a number of adverse outcomes, such as osteoporosis, cardiovascular disease, and cancer. However, the causality of these associations remains unclear. A powerful epidemiological method known as Mendelian randomization (MR) can be used to clarify the causality between ANM and other diseases or traits. The present review describes MR studies that included ANM as an exposure, outcome and mediator. The findings of MR analyses on ANM have revealed that higher body mass index, poor educational level, early age at menarche, early age at first live birth, early age at first sexual intercourse, and autoimmune thyroid disease appear to be involved in early ANM etiology. The etiology of late ANM appears to be influenced by higher free thyroxine 4 and methylene tetrahydrofolate reductase gene mutations. Furthermore, early ANM has been found to be causally associated with an increased risk of osteoporosis, fracture, type 2 diabetes mellitus, glycosylated hemoglobin, and the homeostasis model of insulin resistance level. In addition, late ANM has been found to be causally associated with an increased systolic blood pressure, higher risk of breast cancer, endometrial cancer, endometrioid ovarian carcinoma, lung cancer, longevity, airflow obstruction, and lower risk of Parkinson's disease. ANM is also a mediator for breast cancer caused by birth weight and childhood body size. However, due to the different instrumental variables used, some results of studies are inconsistent. Future studies with more valid genetic variants are needed for traits with discrepancies between MRs or between MR and other types of epidemiological studies.

Genetic prediction of age at menarche, age at natural menopause and type 2 diabetes: A Mendelian randomization study

BACKGROUND AND AIMS

The relationship between reproductive factors and type 2 diabetes (T2D) is controversial; therefore, we explored the causal relationship of age at menarche (AAM), age at natural menopause (ANM), with the risk of T2D and glycemic traits using two-sample Mendelian randomization.

METHODS AND RESULTS

We used publicly available data at the summary level of genome-wide association studies, where AAM (N = 329,345), ANM (N = 69,360), T2D (N = 464,389). The inverse variance weighting (IVW) method was employed as the primary method. To demonstrate the robustness of the results, we also conducted various sensitivity analysis methods including the MR-Egger regression, the weighted median (WM) and the MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test. After excluding IVs associated with confounders, we found a causal association between later AAM and reduced risk of T2D (OR 0.81 [95% CI 0.75, 0.87]; P = 2.20 × 10^-8), lower levels of FI (β -0.04 [95% CI -0.06, -0.01]; P = 2.19 × 10^-3), FPG (β -0.03 [95% CI -0.05, -0.007]; P = 9.67 × 10^-5) and HOMA-IR (β -0.04 [95% CI -0.06, -0.01]; P = 4,95 × 10^-3). As for ANM, we only found a causal effect with HOMA-IR (β -0.01 [95% CI -0.02, -0.005]; P = 1.77 × 10^-3), but not with T2D.

CONCLUSIONS

Our MR study showed a causal relationship between later AAM and lower risk of developing T2D, lower FI, FPG and HOMA-IR levels. This may provide new insights into the prevention of T2D in women.

The interplay between diabetes mellitus and menopause: clinical implications

The menopausal transition is an impactful period in women's lives, when the risk of cardiovascular disease is accelerated. Similarly, diabetes mellitus profoundly impacts cardiovascular risk. However, the interplay between menopause and diabetes mellitus has not been adequately studied. The menopausal transition is accompanied by metabolic changes that predispose to diabetes mellitus, particularly type 2 diabetes mellitus (T2DM), as menopause results in increased risk of upper body adipose tissue accumulation and increased incidence of insulin resistance. Equally, diabetes mellitus can affect ovarian ageing, potentially causing women with type 1 diabetes mellitus and early-onset T2DM to experience menopause earlier than women without diabetes mellitus. Earlier age at menopause has been associated with a higher risk of T2DM later in life. Menopausal hormone therapy can reduce the risk of T2DM and improve glycaemic control in women with pre-existing diabetes mellitus; however, there is not enough evidence to support the administration of menopausal hormone therapy for diabetes mellitus prevention or control. This Review critically appraises studies published within the past few years on the interaction between diabetes mellitus and menopause and addresses all clinically relevant issues, such as the effect of menopause on the development of T2DM, and the management of both menopause and diabetes mellitus.

Menopausal status, age at natural menopause and risk of diabetes in China: a 10-year prospective study of 300,000 women

BACKGROUND

Menopause characteristics have been implicated in future health consequences, yet little is known about its relevance to diabetes. We examined the associations of menopausal status and age at natural menopause with diabetes risk in Chinese women.

METHODS

We used prospective data of the China Kadoorie Biobank study that recruited 302,522 women aged 30-79 years in 2004-2008 from 10 areas across China. During average 10.8 years of follow-up, 11,459 incident diabetes cases were recorded among 281,319 women without prior diabetes diagnosis at baseline. Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for incident diabetes associated with menopausal status and age at natural menopause.

RESULTS

Overall, the mean (SD) age at natural menopause was 48.2 (4.4) years among 141,789 post-menopausal women. Naturally peri-, or post-menopausal women were at higher risk of diabetes, with HRs of 1.17 (95% CI 1.06-1.29) and 1.15 (1.06-1.25) compared with pre-menopausal women, adjusting for several potential confounders. Among women who had natural menopause, the HR of diabetes was 1.14 (1.01-1.30), 1.01 (0.93-1.09), 1.10 (1.04-1.16), and 1.10 (1.01-1.20) for menopause at ages less than 40, 40-44, 50-53, and 54 years or older, respectively, relative to 45-49 years.

CONCLUSIONS

In this study, we found that women with naturally peri-, or post-menopausal status had higher risk of developing diabetes. Besides, among the post-menopausal women, both earlier and later age at natural menopause were associated with increased risk of diabetes.