Endogenous sex hormone levels and coronary heart disease risk in postmenopausal women: A meta-analysis of prospective studies

Sex Hormones, the Stool Microbiome, and Subclinical Atherosclerosis in Women With and Without HIV

CONTEXT

Cardioprotective roles of endogenous estrogens may be particularly important in women with HIV, who have reduced estrogen exposure and elevated cardiovascular disease risk. The gut microbiome metabolically interacts with sex hormones, but little is known regarding possible impact on cardiovascular risk.

OBJECTIVE

To analyze potential interplay of sex hormones and gut microbiome in cardiovascular risk.

METHODS

Among 197 postmenopausal women in the Women's Interagency HIV Study, we measured 15 sex hormones in serum and assessed the gut microbiome in stool. Presence of carotid artery plaque was determined (B-mode ultrasound) in a subset (n = 134). We examined associations of (i) sex hormones and stool microbiome, (ii) sex hormones and plaque, and (iii) sex hormone-related stool microbiota and plaque, adjusting for potential confounders.

RESULTS

Participant median age was 58 years and the majority were living with HIV (81%). Sex hormones (estrogens, androgens, and adrenal precursors) were associated with stool microbiome diversity and specific species, similarly in women with and without HIV. Estrogens were associated with higher diversity, higher abundance of species from Alistipes, Collinsella, Erysipelotrichia, and Clostridia, and higher abundance of microbial β-glucuronidase and aryl-sulfatase orthologs, which are involved in hormone metabolism. Several hormones were associated with lower odds of carotid artery plaque, including dihydrotestosterone, 3α-diol-17G, estradiol, and estrone. Exploratory mediation analysis suggested that estrone-related species, particularly from Collinsella, may mediate the protective association of estrone with plaque.

CONCLUSION

Serum sex hormones are significant predictors of stool microbiome diversity and composition. The gut microbiome may play a role in estrogen-related cardiovascular protection.

Genetically predicted sex hormone levels and health outcomes: phenome-wide Mendelian randomization investigation

BACKGROUND

Sex hormone-binding globulin (SHBG), testosterone and oestradiol have been associated with many diseases in observational studies; however, the causality of associations remains unestablished.

METHODS

A phenome-wide Mendelian randomization (MR) association study was performed to explore disease outcomes associated with genetically proxied circulating SHBG, testosterone and oestradiol levels by using updated genetic instruments in 339 197 unrelated White British individuals (54% female) in the UK Biobank. Two-sample MR analyses with data from large genetic studies were conducted to replicate identified associations in phenome-wide MR analyses. Multivariable MR analyses were performed to investigate mediation effects of hormone-related biomarkers in observed associations with diseases.

RESULTS

Phenome-wide MR analyses examined associations of genetically predicted SHBG, testosterone and oestradiol levels with 1211 disease outcomes, and identified 28 and 13 distinct phenotypes associated with genetically predicted SHBG and testosterone, respectively; 22 out of 28 associations for SHBG and 10 out of 13 associations for testosterone were replicated in two-sample MR analyses. Higher genetically predicted SHBG levels were associated with a reduced risk of hypertension, type 2 diabetes, diabetic complications, coronary atherosclerotic outcomes, gout and benign and malignant neoplasm of uterus, but an increased risk of varicose veins and fracture (mainly in females). Higher genetically predicted testosterone levels were associated with a lower risk of type 2 diabetes, coronary atherosclerotic outcomes, gout and coeliac disease mainly in males, but an increased risk of cholelithiasis in females.

CONCLUSIONS

These findings suggest that sex hormones may causally affect risk of several health outcomes.

Relationships between endogenous and exogenous testosterone and cardiovascular disease in men

In this narrative review, we discuss the evidence about the controversy about the cardiovascular effects of endogenous and exogenous testosterone in men. Prospective cohort studies with follow-up of ~5-15 years generally indicate no association or a possible inverse relationship between serum endogenous testosterone concentrations and composite major cardiovascular events, cardiovascular deaths and overall mortality. Pharmacoepidemiological studies of large databases generally show no association between testosterone therapy and incident major cardiovascular events, and some pharmacoepidemiological studies demonstrate an association with decreased overall mortality. Randomized, placebo-controlled trials indicate that there is no increased incidence of overall major cardiovascular events with 1-3 years of testosterone therapy. These placebo-controlled trials have major limitations including small numbers of participants, short duration of testosterone therapy and follow-up, and lack of systematic adjudication of cardiovascular events. Overall, the evidence indicates that endogenous testosterone concentrations and testosterone therapy at physiological dosages confer no or minimal effects on the incidence of cardiovascular outcomes. There is insufficient evidence to make conclusions about testosterone therapy for patients at high risk of cardiovascular events (e.g., men with recent myocardial infarctions or stroke and men with recurrent idiopathic deep venous thromboses). In general, clinicians should avoid prescribing supraphysiological testosterone therapy to hypogonadal men or men with slightly low to low-normal serum testosterone concentrations and no identified disorder of the hypothalamus-pituitary-testicular axis because of the uncertain cardiovascular risks and the lack of proven health benefits. For most men with bona fide hypogonadism, benefits of testosterone therapy exceed the potential risk of adverse cardiovascular effects.

Circulating sex hormones and risk of atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Sex hormones are associated with many cardiovascular risk factors, but their effects on atrial fibrillation (AF) incidence remain unclear. This systematic review and meta-analysis aimed to evaluate the association of circulating sex hormones with AF risk by pooling available data from observational studies.

METHODS

A systematic literature search for pertinent articles with case-control and cohort designs was conducted via five databases up to 7 July 2021. A meta-analysis with six cohort studies was conducted separately on men and women. Adjusted relative risk (RR) with a 95% confidence interval (CI) was derived by comparing the highest with the lowest levels of a specific sex hormone and by using a random-effect or fixed-effect model. Heterogeneity was tested using the I ² statistic and the Q-test.

RESULTS

A total of six cohort studies and four case-control studies were included. In a meta-analysis of cohort studies, dehydroepiandrosterone sulfate (DHEAS) was associated with a decreased risk of AF in men (RR: 0.729, 95% CI: 0.559-0.952, I ² = 50.0%, P _{-heterogeneity} = 0.157) after combining results from two cohort studies; total testosterone was not associated with any risk of AF in men and postmenopausal women, and AF risk was not associated with estradiol in men after synthesizing available studies.

CONCLUSION

This study indicates that a higher endogenous DHEAS level was associated with a lower AF risk in men, whereas total testosterone and estradiol were not associated with AF risk. Longitudinal studies with multiple monitoring are needed to further promulgate the relationship between various circulating sex hormones and AF risk.

Hysterectomy and ischemic heart disease: An observational study using propensity score methods in NHANES 2007-2018

BACKGROUND AND AIMS

The association between hysterectomy and cardiovascular disease (CVD) remains controversial and research focusing on different types of CVD, especially ischemic heart disease, is scant.

METHODS

This observational study was conducted with the National Health and Nutrition Examination Survey (NHANES) 2007-2018 using propensity score matching, propensity score overlap weighting, and logistic regression.

RESULTS

Among 15,257 women, 3476 (22.78%) had hysterectomy. Compared with non-hysterectomized women, hysterectomized women are more likely to be older, obese, with lower education level, and lower annual family income. Less favorable outcomes often occurred in unadjusted analysis. In adjusted, matched, and weighted analyses, the associations between hysterectomy and all outcomes were consistent, including ischemic heart disease (OR_unadjusted = 3.18[95%CI, 2.76-3.66]; OR_adjusted = 1.38[95%CI, 1.09-1.73]; OR_matched = 1.37[95%CI, 1.07-1.75]; OR_weighted = 1.38[95%CI, 1.12-1.71]), coronary heart disease (OR_unadjusted = 3.31[95%CI, 2.71-4.05]; OR_adjusted = 1.43[95%CI, 1.04-1.98]; OR_matched = 1.46[95%CI, 1.04-2.05]; OR_weighted = 1.45[95%CI, 1.06-1.99]), heart attack (OR_unadjusted = 3.04[95%CI, 2.51-3.68]; OR_adjusted = 1.47[95%CI, 1.09-1.99]; OR_matched = 1.42[95%CI, 1.03-1.95]; OR_weighted = 1.45[95%CI, 1.10-1.91]) and angina pectoris (OR_unadjusted = 3.29[95%CI, 2.66-4.08]; OR_adjusted = 1.34[95%CI, 0.95-1.89]; OR_matched = 1.30[95%CI, 0.91-1.87]; OR_weighted = 1.33[95%CI, 0.98-1.81]). In hysterectomized women, there were no significant associations between bilateral ovariectomy and ischemic heart disease (OR_unadjusted = 1.24[95%CI, 0.99-1.54]; OR_adjusted = 1.05[95%CI, 0.80-1.38]; OR_matched = 1.16[95%CI, 0.86-1.55]; OR_weighted = 0.93[95%CI, 0.68-1.27]), female hormones use and ischemic heart disease (OR_unadjusted = 0.94[95%CI, 0.76-1.16]; OR_adjusted = 0.81[95%CI, 0.62-1.07]; OR_matched = 0.89[95%CI, 0.66-1.20]; OR_weighted = 1.14[95%CI, 0.88-1.49]).

CONCLUSIONS

Hysterectomy may increase the risk of ischemic heart disease, especially for coronary heart disease and heart attack, but not for angina pectoris. As for the hysterectomized women, bilateral ovariectomy and female hormones use do not affect ischemic heart disease.

Low testosterone levels are predictive for incident atrial fibrillation and ischaemic stroke in men, but protective in women - results from the FINRISK study

Background Atrial fibrillation is the most common serious abnormal heart rhythm, and a frequent cause of ischaemic stroke. Recent experimental studies, mainly in orchiectomised rats, report a relationship between sex hormones and atrial electrophysiology and electroanatomy. We aimed to evaluate whether low testosterone levels are predictive for atrial fibrillation and/or ischaemic stroke in men and women. Design and methods The serum total testosterone levels were measured at baseline in a population cohort of 7892 subjects (3876 male, 4016 female), aged 25-74 years, using a commercially available immunoassay. The main outcome measure was atrial fibrillation or ischaemic stroke, whichever came first. Results During a median follow-up of 13.8 years, a total of 629 subjects (8.0%) suffered from incident atrial fibrillation ( n = 426) and/or ischemic stroke ( n = 276). Cox regression analyses, adjusted for age (used as time-scale), geographical region, total cholesterol (log), high-density lipoprotein-cholesterol (log), hypertension medication, known diabetes, smoking status, waist-hip-ratio, and time of blood drawn, documented differential predictive value of low sex-specific testosterone levels for atrial fibrillation and/or ischaemic stroke, in men and in women: Increasing levels were associated with lower risk in men (hazard ratio per one nmol/l increase 0.98 (95% confidence interval 0.93-1.00); p = 0.049). On the other hand, increasing testosterone levels were associated with higher risk in women (hazard ratio per one nmol/l increase 1.17 (95% confidence interval 1.02-1.36); p = 0.031). Conclusion Our study indicates that low testosterone levels are associated with increased risk of future atrial fibrillation and/or ischaemic stroke in men, while they are protective in women.