As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.

As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.
Cardiovascular Diseases/mortality* ; Dihydrotestosterone/metabolism* ; Estradiol/metabolism* ; Humans ; Incidence ; Male ; Mortality ; Myocardial Infarction/metabolism* ; Stroke/metabolism* ; Testosterone/metabolism*

Objective: Patients undergoing coronary artery bypass graft (CABG) surgery remain at high cardiovascular risk; however, few studies have evaluated lipid management and attainment of lipid targets in these patients. We investigated the proportion of CABG surgery patients who attained low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (HDL-C) targets. Methods: Data were retrospectively obtained from patients undergoing CABG surgery at an Australian tertiary hospital between February 2015 and August 2020. The most recent lipid profile was recorded (at least 3 weeks post-operatively). We studied patients with electronically available data to ensure accuracy. Target LDL-C was defined as <1.4 (54 mg/dL) and <1.8 mmol/L (70 mg/dL), and target non-HDL-C as <2.2 (85 mg/dL) and <2.6 mmol/L (100 mg/dL), as per the 2019 and 2016 European dyslipidaemia guidelines, respectively. Results: Follow-up lipid results were available for 484 patients (median post-operative follow-up, 483 days; interquartile range, 177.5–938.75 days). The mean age was 62.7±10.5 years and 387 (80.1%) were male. At discharge, 469 (96.9%) patients were prescribed statins, 425 (90.6%) high-intensity. Ezetimibe was prescribed for 62 (12.8%) patients and a proprotein convertase subtilisin-kexin type 9 inhibitor for 1. LDL-C levels <1.4 and <1.8 mmol/L were attained in 118 (24.4%) and 231 (47.7%) patients, respectively, and non-HDL-C levels <2.2 and <2.6 mmol/L in 140 (28.9%) and 237 (49.0%) patients, respectively. Conclusion The use of non-statin lipid-lowering therapies was limited, and many CABG surgery patients did not attain lipid targets despite high-intensity statins. Further studies are required to optimise lipid management in this very high-risk population.

Epidemiological studies hint at a beneficial influence of endogenous circulating testosterone (T), or its metabolite dihydrotestosterone (DHT), such that men with lower concentrations of T or DHT appear to have poorer health outcomes including frailty, diabetes, cardiovascular disease, and mortality. Small interventional studies of T have shown favorable effects on surrogate outcome measures, but a large randomized controlled trial (RCT) with the prespecified outcome of cardiovascular events has not been performed and would be logistically demanding. In the absence of such a definitive RCT, there is a controversy about the cardiovascular risks of T-therapy fuelled by contradictory findings from retrospective analyses of insurance databases of men prescribed T. The US Testosterone Trials (T-Trials) are the largest published RCTs of T-therapy in older men with symptoms or signs of hypogonadism and circulating T <9.54 nmol l⁻¹ at baseline. The T-Trials showed a modest benefit of T-therapy over a 12-month period on sexual function, a significant benefit in bone density and for anemia and neutral effect on cognition. The T-Trials cardiovascular sub-study was designed to determine the effects of T in these older men, and there was a statistically significant difference in the increase in noncalcified plaque volume in the T-treated group compared to placebo, but it is difficult to interpret these results due to differences in baseline coronary plaque burden (>50% difference) between the treatment and placebo arms of the subset involved. Therefore, there continues to be ongoing uncertainty over the effect of T-therapy on the cardiovascular system in men.
Age Factors ; Androgens/therapeutic use* ; Cardiovascular Diseases/metabolism* ; Dihydrotestosterone/metabolism* ; Hormone Replacement Therapy ; Humans ; Hypogonadism/metabolism* ; Male ; Protective Factors ; Risk Factors ; Testosterone/therapeutic use*

In this issue of Asian Journal of Andrology (AJA), several experts have reviewed the latest data on the potential and known effects of endogenous and exogenous testosterone (T) on cardiovascular risk. In the review by Meyer and Wittert, low endogenous serum T appears to be associated with higher risk of cardiovascular disease and overall mortality in certain populations such as Klinefelter syndrome and older men, but not in men with congenital hypogonadotropic hypogonadism. Whether this association is causal or whether low serum testosterone is a marker of other risk factors for cardiovascular disease such as obesity, diabetes mellitus, or other systemic disease is unknown. In Yeap's review of the relationship between circulating endogenous testosterone and its major metabolites, dihydrotestosterone, and estradiol, he raises the provocative hypotheses that there might be differential effects on cardiovascular and cerebrovascular risk related to endogenous testosterone and dihydrotestosterone concentrations. Based on the same epidemiological studies, Yeap postulates that there might be a U-shaped curve for circulating endogenous androgen concentrations such that lower and higher concentrations might confer greater risk of cardiovascular events and all-cause mortality than midrange concentrations. Shores demonstrates in a carefully done review of studies of large prescription databases (including >200 000 men) that testosterone therapy is not associated with overall mortality, myocardial infarction, stroke, or deep venous thrombosis events.
Cardiovascular Diseases ; Cardiovascular System ; Humans ; Hypogonadism ; Risk Factors ; Testosterone