Viewpoint

Myth and paradox of coronary risk and the menopause

Pharmacologic intervention is one of the cornerstones of management for hypertension. However, potential adverse drug reactions, drug-drug interaction, as well as safety and effectiveness in certain medical conditions such as chronic kidney disease, end-stage kidney disease, pregnancy, postsurgery, or transplantation limit the flexible use of some antihypertensive medications. Therefore, nonpharmacologic interventions are another therapeutic option for hypertension. Several modalities of nonpharmacologic intervention have been proven to be effective for blood pressure management, and among those, dietary intervention is one of the most widely used options and has long been of interest to every stakeholder involved in hypertensive care including health care providers, public health professionals, patients and their caregivers, and public health policymakers. Specific main nutrients, both micro- and macronutrients, which contribute to elevated blood pressure with different mechanisms are sodium, phosphorus, carbohydrate, protein, saturated, monounsaturated, and trans unsaturated fatty acids; while potassium, calcium, vitamin D, and polyunsaturated fatty acid are protective for hypertension. However, instead of a single nutrient, a dietary pattern is a practical approach to implement the dietary intervention, and a variety of “healthy” diets have been recommended for blood pressure management. Plant-dominant and plant-forward diets, such as Dietary Approaches to Stop Hypertension (DASH), Mediterranean, and vegetarian diets, have been shown to have a favorable effect on blood pressure. Apart from increased effective circulatory blood volume, enhanced renin-angiotensin-aldosterone system, and activated sympathetic nervous system, inflammatory milieu and dysregulation of the immune system originating from gut microbiome dysbiosis are proposed to link those pathophysiologic changes and responsible organs including the brain, heart, intestine, and kidney to initiate and perpetuate hypertension. Particularly, some underlying medical conditions, especially chronic diseases such as CKD or novel diseases like coronavirus disease 2019 (COVID-19) causing perturbation of physiologic and involved organ systems, can be challenging in blood pressure control with only antihypertensive medications and multi-modal therapies including dietary intervention is crucial.

Monocyte chemokine receptor 2 (CCR2) and phosphorylated extra-cellular regulated kinase 1 & 2 (ERK1/2) impact macrophage differentiation and progression of atherosclerosis. Whereas aerobic exercise favorably modulates the immune system and reduces atherosclerotic risk, it is unknown whether sex differences exist in the monocyte/macrophage response to acute aerobic exercise.

To determine the impact of an acute bout of moderate intensity aerobic exercise on monocyte and macrophage CCR2 expression, ERK1/2 phosphorylation, and macrophage polarization in pre-menopausal women and men.

Blood samples were collected in 24 people (Women/Men; n = 12) prior to (PRE), immediately after a bout of moderate intensity cycle ergometry (POST), and 2 h (2H) following exercise. Monocyte and macrophage CCR2 and phosphorylated ERK1/2 as well as macrophage CD86 and CD206 were analyzed by flow cytometry.

PRE classical monocyte CCR2 expression was greater in women compared to men (Women: 20546.2 ± 2306.4 vs. Men: 14437.6 ± 1201.9 AUF; p = 0.028) and was reduced in women at 2H (PRE: 20546.2 ± 2306.4 vs. 2H: 15856.9 ± 1314.4 AUF; p = 0.027). POST classical monocyte CCR2 expression was inversely associated (r = −0.697, p = 0.012) with POST classical monocyte ERK1/2 phosphorylation in women only. The percentage of CCR2⁺ macrophages was lower in women at POST (Women: 62.0 ± 8.9 vs. Men: 83.6 ± 3.1; p = 0.031) and at 2H (Women: 60.3 ± 8.4 vs. Men: 83.5 ± 3.0%; p = 0.016).

These data suggest that a single bout of moderate intensity aerobic exercise differentially impacts monocyte CCR2 expression and macrophage polarization in women compared to men.

Early menopause is linked to an increased risk of cardiovascular disease mortality; however, the association between early menopause and incidence and timing of cardiovascular disease is unclear. We aimed to assess the associations between age at natural menopause and incidence and timing of cardiovascular disease.

We harmonised and pooled individual-level data from 15 observational studies done across five countries and regions (Australia, Scandinavia, the USA, Japan, and the UK) between 1946 and 2013. Women who had reported their menopause status, age at natural menopause (if postmenopausal), and cardiovascular disease status (including coronary heart disease and stroke) were included. We excluded women who had hysterectomy or oophorectomy and women who did not report their age at menopause. The primary endpoint of this study was the occurrence of first non-fatal cardiovascular disease, defined as a composite outcome of incident coronary heart disease (including heart attack and angina) or stroke (including ischaemic stroke or haemorrhagic stroke). We used Cox proportional hazards models to estimate multivariate hazard ratios (HRs) and 95% CIs for the associations between age at menopause and incident cardiovascular disease event. We also adjusted the model to account for smoking status, menopausal hormone therapy status, body-mass index, and education levels. Age at natural menopause was categorised as premenopausal or perimenopausal, younger than 40 years (premature menopause), 40–44 years (early menopause), 45–49 years (relatively early), 50–51 years (reference category), 52–54 years (relatively late), and 55 years or older (late menopause).

Overall, 301 438 women were included in our analysis. Of these 301 438 women, 12 962 (4·3%) had a first non-fatal cardiovascular disease event after menopause, of whom 9369 (3·1%) had coronary heart disease and 4338 (1·4%) had strokes. Compared with women who had menopause at age 50–51 years, the risk of cardiovascular disease was higher in women who had premature menopause (age <40 years; HR 1·55, 95% CI 1·38–1·73; p<0·0001), early menopause (age 40–44 years; 1·30, 1·22–1·39; p<0·0001), and relatively early menopause (age 45–49 years; 1·12, 1·07–1·18; p<0·0001), with a significantly reduced risk of cardiovascular disease following menopause after age 51 years (p<0·0001 for trend). The associations persisted in never smokers, and were strongest before age 60 years for women with premature menopause (HR 1·88, 1·62–2·20; p<0·0001) and early menopause (1·40, 1·27–1·54; p<0·0001), but were attenuated at age 60–69 years, with no significant association observed at age 70 years and older.

Compared with women who had menopause at age 50–51 years, women with premature and early menopause had a substantially increased risk of a non-fatal cardiovascular disease event before the age of 60 years, but not after age 70 years. Women with earlier menopause need close monitoring in clinical practice, and age at menopause might also be considered as an important factor in risk stratification of cardiovascular disease for women.

Australian National Health and Medical Research Council.

The contentious effects of estrogen therapy on the risk of postmenopausal cardiovascular disease (CVD) indicate that this type of atherosclerosis is not solely induced by estrogen deficiency. Other sex hormones such as elevated luteinizing hormone (LH) may also affect CVD risk in this population. We therefore explored the relationship between LH and atherosclerosis in ovariectomized (OVX) female mice.

Aortic atherosclerotic lesions were assessed in OVX ApoE knock out (ApoE^−/−) female mice administered with LH. Human umbilical vascular endothelial cells (HUVECs) were cultured as cell model. The influence of LH on NO release, phosphorylated endothelial nitric oxide synthase (eNOS) and Akt levels were evaluated. Immunoprecipitation and lentiviral particle transfection were applied to assess the role of Gαq on PI3K activity.

LH increased the atherosclerotic lesion area and carotid artery intima-media thickness (IMT) in OVX ApoE^−/− female mice. High levels of LH attenuated vasodilation induced by Ach and inhibited NO release from HUVECs. These effects were related to the findings that LH enhanced interaction between Gαq and p110α, which subsequently inhibited PI3K activity and suppressed the phosphorylation of Akt and eNOS.

Elevated LH promotes atherosclerosis formation in OVX ApoE^−/− female mice. This effect may be mediated by inhibiting endothelial NO synthesis via PI3K/Akt signaling pathway.

While a mean age at menopause of 51 years has been reported in the United States (U.S.), some U.S. women experience menopause before age 45, possibly increasing risk of cardiovascular mortality; however, the role in all-cause and cerebrovascular-related mortality is unclear. The purpose of this study was to investigate the association between age at menopause and all-cause and cause-specific mortality by race, hormone replacement therapy (HRT) use, and smoking status. REasons for Geographic and Racial Differences in Stroke (REGARDS) is a population-based study of 30,239 participants aged ≥45 years enrolled between 2003 and 2007 of whom 14,361 were postmenopausal women. Age at menopause was defined as <45 (early) or ≥45. All-cause and cause-specific mortality were ascertained through 2013. Cox proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for the association between age at menopause and mortality, adjusting for baseline measures. Of 11,287 eligible women (6403 white; 4884 black), mean menopause age was 45.2 (SD 7.9) with 1524 deaths over 7.1 years. Significant interactions were detected between early age at menopause (39%) and HRT use in association with all-cause mortality (p < 0.01), mortality from coronary heart disease (p = 0.06), and mortality from all other causes (p = 0.04). An association between early age at menopause and all-cause mortality was observed among ever-HRT users (HR = 1.31, 95% CI: 1.10–1.56), but not never-HRT users (HR = 1.01, 95% CI: 0.85–1.20). There were no differences in associations examined by race or smoking status. Increased all-cause mortality risk was observed for ever-HRT users with menopause before age 45.

Reproductive factors reflective of endogenous sex hormone exposure might have an effect on cardiac remodeling and the development of heart failure (HF).

This study examined the association between key reproductive factors and the incidence of HF.

Women from a cohort of the Women's Health Initiative were systematically evaluated for the incidence of HF hospitalization from study enrollment through 2014. Reproductive factors (number of live births, age at first pregnancy, and total reproductive duration [time from menarche to menopause]) were self-reported at study baseline in 1993 to 1998. We employed Cox proportional hazards regression analysis in age- and multivariable-adjusted models.

Among 28,516 women, with an average age of 62.7 ± 7.1 years at baseline, 1,494 (5.2%) had an adjudicated incident HF hospitalization during an average follow-up of 13.1 years. After adjusting for covariates, total reproductive duration in years was inversely associated with incident HF: hazard ratios (HRs) of 0.99 per year (95% confidence interval [CI]: 0.98 to 0.99 per year) and 0.95 per 5 years (95% CI: 0.91 to 0.99 per 5 years). Conversely, early age at first pregnancy and nulliparity were significantly associated with incident HF in age-adjusted models, but not after multivariable adjustment. Notably, nulliparity was associated with incident HF with preserved ejection fraction in the fully adjusted model (HR: 2.75; 95% CI: 1.16 to 6.52).

In post-menopausal women, shorter total reproductive duration was associated with higher risk of incident HF, and nulliparity was associated with higher risk for incident HF with preserved ejection fraction. Whether exposure to endogenous sex hormones underlies this relationship should be investigated in future studies.