Sex hormones and the risk of atrial fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Testosterone and the risk of incident atrial fibrillation in older men: further analysis of the ASPREE study

Background

A cardiovascular safety trial of testosterone in men with cardiovascular risk factors or disease found no difference in rates of major adverse cardiovascular events (MACE) or death but noted more atrial fibrillation (AF) events in testosterone-treated men. We investigated the relationship between endogenous testosterone concentrations with risk of developing AF in healthy older men.

Methods

Post-hoc analysis of 4570 male participants in the ASPirin in Reducing Events in the Elderly (ASPREE) study. Men were aged ≥ 70 years, had no history of cardiovascular disease (including AF), thyroid disease, prostate cancer, dementia, or life-threatening illnesses. Risk of AF was modelled using Cox proportional hazards regression.

Findings

Median (IQR) age was 73.7 (71.6-77.1) years and median (IQR) follow-up 4.4 (3.3-5.5) years, during which 286 men developed AF (15.3 per 1000 participant-years). Baseline testosterone was higher in men who developed incident AF compared men who did not [17.0 (12.4-21.2) vs 15.7 (12.2-20.0) nmol/L]. There was a non-linear association of baseline testosterone with incident AF. The risk for AF was higher in men with testosterone in quintiles (Q) 4&5 (Q4:Q3, HR = 1.91; 95%CI = 1.29-2.83 and Q5:Q3HR = 1.98; 95%CI = 1.33-2.94). Results were similar after excluding men who experienced MACE or heart failure during follow-up.

Interpretation

Circulating testosterone concentrations within the high-normal range are independently associated with an increased risk of incident AF amongst healthy older men. This suggests that AF may be an adverse consequence of high-normal total testosterone concentrations.

Funding

National Institute on Aging and National Cancer Institute at the National Institutes of Health; Australian Government (NHMRC, CSIRO); Monash University; and AlfredHealth.

Cardiovascular safety of testosterone replacement therapy in men: an updated systematic review and meta-analysis

INTRODUCTION

The cardiovascular (CV) safety of testosterone (T) replacement therapy (TRT) is still conflicting. Recent data suggested a TRT-related increased risk of atrial fibrillation (AF). The aim of this study was to systematic review and meta-analyze CV risk related to TRT as derived from placebo controlled randomized trials (RCTs).

AREAS COVERED

An extensive Medline, Embase, and Cochrane search was performed. All placebo-controlled RCTs reporting data on TRT-related CV safety were considered. To better analyze the role of T on AF, population-based studies investigating the relationship between endogenous circulating T levels and AF incidence were also included and analyzed.

EXPERT OPINION

Out of 3.615, 106 studies were considered, including 8.126 subjects treated with TRT and 7.310 patients allocated to placebo. No difference between TRT and placebo was observed when major adverse CV events were considered. Whereas the incidence of non-fatal arrhythmias and AF was increased in the only trial considering CV safety as the primary endpoint, this was not confirmed when all other studies were considered (MH-OR 1.61[0.84;3.08] and 1.44[0.46;4.46]). Similarly, no relationship between endogenous T levels and AF incidence was observed after the adjustment for confounders Available data confirm that TRT is safe and it is not related to an increased CV risk.

Drug-induced atrial fibrillation. A narrative review of a forgotten adverse effect

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased morbidity and mortality. There is clinical evidence that an increasing number of cardiovascular and non-cardiovascular drugs, mainly anticancer drugs, can induce AF either in patients with or without pre-existing cardiac disorders, but drug-induced AF (DIAF) has not received the attention that it might deserve. In many cases DIAF is asymptomatic and paroxysmal and patients recover sinus rhythm spontaneously, but sometimes, DIAF persists, and it is necessary to perform a cardioversion. Furthermore, DIAF is not mentioned in clinical guidelines on the treatment of AF. The risk of DIAF increases in elderly and in patients treated with polypharmacy and with risk factors and comorbidities that commonly coexist with AF. This is the case of cancer patients. Under these circumstances ascribing causality of DIAF to a given drug often represents a clinical challenge. We review the incidence, the pathophysiological mechanisms, risk factors, clinical relevance, and treatment of DIAF. Because of the limited information presently available, further research is needed to obtain a deeper insight into DIAF. Meanwhile, it is important that clinicians are aware of the problem that DIAF represents, recognize which drugs may cause DIAF, and consider the possibility that a drug may be responsible for a new-onset AF episode.

Associations of Serum Testosterone and Sex Hormone-binding Globulin With Incident Arrhythmias in Men From UK Biobank

CONTEXT

Sex hormones have been identified as cardiovascular risk factors, whereas the relationship between sex hormones and the risk of arrhythmias in men has not yet been well studied in the prospective cohort study.

OBJECTIVE

To analyze associations of serum testosterone and SHBG concentrations and calculate free testosterone (cFT) with arrhythmias in men.

METHODS

Sex hormones were measured at baseline from UK Biobank. Main outcomes were incidence of atrial fibrillation/flutter (AF), ventricular arrhythmia (VA), and bradyarrhythmia (BA).

RESULTS

Of 173 498 men (aged 37-73 years, followed for 11 years), 11 368 had incident AF, 1646 had incident VA, and 4788 had incident BA. Compared with the third quartiles, the lowest category of serum testosterone was associated with increased risks of AF (hazard ratio [HR], 1.06; 95% CI, 1.00-1.12) and BA (HR, 1.11; 95% CI, 1.02-1.20) after multivariable adjustment, but no VA. Likewise, similar associations were found between cFT values and AF and BA events. Furthermore, higher levels of cFT were associated with increased risks of AF (HR, 1.07; 95% CI, 1.02-1.13) and VA (HR, 1.18; 95% CI, 1.01-1.37). Higher SHBG concentrations were associated with increased risks of AF (HR, 1.44; 95% CI, 1.34-1.54), VA (HR, 1.27; 95% CI, 1.07-1.52), and BA (HR, 1.17; 95% CI ,1.05-1.29).

CONCLUSIONS

Lower levels of testosterone and cFT were associated with increased risk of AF and BA. Higher cFT levels were associated with increased risk of AF and VA. Higher SHBG levels were associated with increased risk of AF, VA, and BA.

Height Explains Sex Difference in Atrial Fibrillation Risk: Copenhagen General Population Study

OBJECTIVE

To test the hypothesis that the increased risk of atrial fibrillation (AF) in men compared with women is explained by height.

METHODS

From the Copenhagen General Population Study, we included 106,207 individuals (47,153 men and 59,054 women) from 20 to 100 years of age, without a prior diagnosis of AF, examined between November 25, 2003, and April 28, 2015. The main outcome was AF incidence from national hospital registers until April 2018. The association of risk factors with AF incidence was assessed by cause-specific Cox proportional hazards regression and Fine-Gray subdistribution hazards regression analysis.

RESULTS

During a maximum of 14.4 years of follow-up (median, 8.9 years), incident AF was observed in 3449 men and 2772 women with 845 (95% CI, 815 to 875) and 514 (95% CI, 494 to 535) events per 100,000 person-years, respectively. The age-adjusted hazard of incident AF was 63% (95% CI, 55% to 72%) higher in men compared with women. Risk factors for AF were generally similar in men and women, except men were taller than women (179 cm vs 166 cm, respectively; P<.001). When controlling for height, the difference in hazard of incident AF between sexes disappeared. For population attributable risk of AF, height was the most important risk factor investigated and explained 21% and 19% of the risk of incident AF in men and women, respectively.

CONCLUSION

A 63% higher risk of incident AF in men compared with women is explained by differences in height.

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.

Connexin Lateralization Contributes to Male Susceptibility to Atrial Fibrillation

Men have a higher risk of developing atrial fibrillation (AF) than women, though the reason for this is unknown. Here, we compared atrial electrical and structural properties in male and female mice and explored the contribution of sex hormones. Cellular electrophysiological studies revealed that action potential configuration, Na+ and K+ currents were similar in atrial myocytes from male and female mice (4–5 months). Immunofluorescence showed that male atrial myocytes had more lateralization of connexins 40 (63 ± 4%) and 43 (66 ± 4%) than females (Cx40: 45 ± 4%, p = 0.006; Cx43: 44 ± 4%, p = 0.002), with no difference in mRNA expression. Atrial mass was significantly higher in males. Atrial myocyte dimensions were also larger in males. Atrial fibrosis was low and similar between sexes. Orchiectomy (ORC) abolished sex differences in AF susceptibility (M: 65%; ORC: 38%, p = 0.050) by reducing connexin lateralization and myocyte dimensions. Ovariectomy (OVX) did not influence AF susceptibility (F: 42%; OVX: 33%). This study shows that prior to the development of age-related remodeling, male mice have more connexin lateralization and larger atria and atrial myocyte than females. Orchiectomy reduced AF susceptibility in males by decreasing connexin lateralization and atrial myocyte size, supporting a role for androgens. These sex differences in AF substrates may contribute to male predisposition to AF.

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.

A Population-Based Study of Unexplained/Lone Atrial Fibrillation: Temporal Trends, Management, and Outcomes

Background

Previous studies on lone/unexplained atrial fibrillation and atrial flutter (AF) did not exclude patients with contemporary secondary AF triggers. We characterized unexplained AF using a strict definition, and compared it to secondary AF.

Methods

In this population-based study, unexplained AF was defined by the lack of any identifiable triggering medical/surgical diagnosis. Comparisons by AF type (unexplained vs secondary), age-of-onset (≤ / > 65 years), and sex were undertaken. Data were acquired by linking 6 population databases maintained by the Alberta Ministry of Health over a 9-year period (April 2006 to March 2015). The primary composite outcome of stroke, transient ischemic attack, thromboembolism, and/or death was assessed.

Results

There were 33,150 incident AF diagnoses identified, including 1145 patients (3.5%) with unexplained AF, 931 (81.2%) of whom were aged ≤ 65 years (2.8% of diagnoses, and 79% male). Patients with unexplained AF less often received rate/rhythm-control drugs (P < 0.0001), but they more often underwent electrical cardioversion (P < 0.0001) vs secondary AF patients. Men were younger at unexplained AF diagnosis (45 [interquartile range: 34-59] vs 58 [interquartile range: 40-69] years; P < 0.001). After adjusting for age at diagnosis, there were no sex-based differences in the primary outcome. Event-free survival in young unexplained AF (age ≤ 65 years) was 99.4% at 1 year and 98.3% at 3 years. At 3 years, hospitalization(s)/emergency visit(s) for noncardiovascular reasons and for AF occurred in 56.6% and 23.8% of these patients, respectively.

Conclusions

Using a strict contemporary definition of unexplained AF, this study shows that the condition is rare, predominantly male, and has excellent event-free survival. However, the high rate of acute hospital utilization after diagnosis is concerning.

Establishment and evaluation of a nomogram prediction model for recurrence risk of atrial fibrillation patients after radiofrequency ablation

OBJECTIVE

To explore the risk factors for recurrence of atrial fibrillation (AF) in patients after radiofrequency ablation and construction of a targeted nomogram prediction model.

METHODS

A prospective cohort study design was used to select 312 patients who were separated into two groups; a recurrence group (n = 79) and a non-recurrence group (n = 233) with or without AF, who underwent radiofrequency ablation for the first time between January 2017 and December 2017, with a completed a 12-month follow-up after surgery. The recurrence of AF within 12 months after follow-up was recorded. The nomogram prediction model was established. The original data were resampled using the Bootstrap method. The recurrence risk after resampling was predicted using a nomogram model. The calibration curve and ROC curve of the nomogram model were established. The predicted calibration degree and discrimination degree of the nomogram model were evaluated with the Hosmer-Lemeshow deviation test and area under the curve.

RESULTS

The 12-month follow-up showed that a total of 79 patients (25.32%) had recurrence of AF. The type of AF, sex, gender, disease course, left atrial anteroposterior diameter, left atrial volume, and cardiac function classification were independent risk factors for the recurrence of AF (P < 0.05). After the nomogram prediction model passed the Bootstrap self-sampling 1000 times, Hosmer-Lemeshow deviation test: χ² = 8.070, P = 0.427; the area under ROC curve was 0.852 (95% CI: 0.806-0.898), the sensitivity was 78.48%, and the specificity was 81.12%, suggesting that the nomogram model has better predictive calibration and discrimination.

CONCLUSION

The recurrence rate in patients with AF after radiofrequency ablation is high. The nomogram model based on the risk factors of AF recurrence has high prediction accuracy and can be used to predict the recurrence risk of AF in patients after radiofrequency ablation.

Revealing the Influences of Sex Hormones and Sex Differences in Atrial Fibrillation and Vascular Cognitive Impairment

The impacts of sex differences on the biology of various organ systems and the influences of sex hormones on modulating health and disease have become increasingly relevant in clinical and biomedical research. A growing body of evidence has recently suggested fundamental sex differences in cardiovascular and cognitive function, including anatomy, pathophysiology, incidence and age of disease onset, symptoms affecting disease diagnosis, disease severity, progression, and treatment responses and outcomes. Atrial fibrillation (AF) is currently recognized as the most prevalent sustained arrhythmia and might contribute to the pathogenesis and progression of vascular cognitive impairment (VCI), including a range of cognitive deficits, from mild cognitive impairment to dementia. In this review, we describe sex-based differences and sex hormone functions in the physiology of the brain and vasculature and the pathophysiology of disorders therein, with special emphasis on AF and VCI. Deciphering how sex hormones and their receptor signaling (estrogen and androgen receptors) potentially impact on sex differences could help to reveal disease links between AF and VCI and identify therapeutic targets that may lead to potentially novel therapeutic interventions early in the disease course of AF and VCI.

Ventricular Tachyarrhythmia Risk in Paediatric/Young vs. Adult Brugada Syndrome Patients: A Territory-Wide Study

Introduction: Brugada syndrome (BrS) is a cardiac ion channelopathy with a higher prevalence in Asia compared to the Western populations. The present study compared the differences in clinical and electrocardiographic (ECG) presentation between paediatric/young (≤25 years old) and adult (>25 years) BrS patients.

Method: This was a territory-wide retrospective cohort study of consecutive BrS patients presenting to public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).

Results: The cohort consists of 550 consecutive patients (median age of initial presentation = 51 ± 23 years; female = 7.3%; follow-up period = 83 ± 80 months), divided into adult (n = 505, mean age of initial presentation = 52 ± 19 years; female = 6.7%; mean follow-up period = 83 ± 80 months) and paediatric/young subgroups (n = 45, mean age of initial presentation = 21 ± 5 years, female = 13.3%, mean follow-up period = 73 ± 83 months). The mean annual VT/VF incidence rate were 17 and 25 cases per 1,000 patient-year, respectively. Multivariate analysis showed that initial presentation of type 1 pattern (HR = 1.80, 95% CI = [1.02, 3.15], p = 0.041), initial asymptomatic presentation (HR = 0.26, 95% CI = [0.07, 0.94], p = 0.040) and increased P-wave axis (HR = 0.98, 95% CI = [0.96, 1.00], p = 0.036) were significant predictors of VT/VF for the adult subgroup. Only initial presentation of VT/VF was predictive (HR = 29.30, 95% CI = [1.75, 492.00], p = 0.019) in the paediatric/young subgroup.

Conclusion: Clinical and ECG presentation of BrS vary between the paediatric/young and adult population in BrS. Risk stratification and management strategies for younger patients should take into consideration and adopt an individualised approach.

Association of Serum Testosterone and Luteinizing Hormone With Blood Pressure and Risk of Cardiovascular Disease in Middle-Aged and Elderly Men

Background

The age‐related decline in testosterone levels is thought to be of great importance for male aging and cardiovascular diseases. However, data are controversial on whether abnormal sex hormones are linked to the presence of cardiovascular diseases and it is also uncertain how blood pressure modifies the association between testosterone levels and major cardiovascular diseases.

Methods and Results

This is a multicenter, population‐based, cross‐sectional study of 6296 men conducted between 2013 and 2016. Basic information and clinical symptoms were obtained by questionnaires. Blood pressure and plasma levels of total testosterone, sex hormone–binding globulin, luteinizing hormone, and free testosterone were determined in men in a multistage random, cluster sampling in 6 provinces of China. There were 5786 Chinese men (mean [SD] age 55.0 [10.1] years) included after exclusion criteria were applied; 37.2% (2150) of them were diagnosed with hypertension. Total testosterone, free testosterone, and sex hormone–binding globulin were inversely associated with the prevalence of hypertension. Age >65 years or body mass index ≥24 negatively impacted the inverse correlation between testosterone levels and hypertension, whereas smoking and family history of hypertension strengthened the correlation. In participants with grade 2 hypertension, total testosterone was positively associated with the presence of stroke, and luteinizing hormone was also positively correlated with cardiovascular and cerebrovascular diseases.

Conclusions

Lower total testosterone could be a promising risk marker for prevalent hypertension. Both low and high levels of testosterone are associated with greater cardiovascular risk. Primary hypogonadism may be a risk marker for major cardiovascular diseases in men with severe hypertension.

Epidemiology of Atrial Fibrillation: Geographic/Ecological Risk Factors, Age, Sex, Genetics

Atrial fibrillation is the most common arrhythmia globally. The global prevalence of atrial fibrillation is positively correlated with the sociodemographic index of different regions. Advancing age, male sex, and Caucasian race are risk factors; female sex is correlated with higher atrial fibrillation mortality worldwide likely owing to thromboembolic risk. African American ethnicity is associated with lower atrial fibrillation risk, same as Asian and Hispanic/Latino ethnicities compared with Caucasians. Atrial fibrillation may be heritable, and more than 100 genetic loci have been identified. A polygenic risk score and clinical risk factors are feasible and effective in risk stratification of incident disease.

Increased risk of atrial fibrillation in patients with Behçet's disease: A nationwide population-based study

BACKGROUND

Chronic inflammation plays a role in the pathophysiology of atrial fibrillation (AF). However, there is a paucity of information about whether Behçet's disease (BD) is associated with an increased risk of AF. This population-based study aimed to determine the risk of AF in patients with BD.

METHODS

A total of 6636 newly diagnosed BD patients without a history of AF were included from the Korean National Health Insurance Service database between 2010 and 2014. Newly diagnosed non-valvular AF was identified using the claims data. An age- and sex-matched non-BD subjects were extracted at a ratio of 1:5 (n = 31,040). The incidence and risk of AF were compared between groups.

RESULTS

During a mean follow-up of 3.6 ± 1.5 years, AF was newly diagnosed in 173 patients (51 in the BD group, 122 in the control group). The incidence was 2.3 and 1.1 per 1000 person-years, respectively. After adjustment, the BD group showed a 1.8-fold higher risk of AF compared to the control group. Patients with BD aged ≤40 years had a higher risk of AF, while patients aged ≥65 years showed a similar risk. Men with BD had a 2.5-fold increased risk of AF, whereas women with BD did not. Severe BD had a higher risk for AF compared to non-severe BD and controls.

CONCLUSIONS

BD was associated with an increased risk of AF, particularly in men and young patients. Active surveillance and treatment are needed in BD patients and those with arrhythmic symptoms.

Plasma total testosterone and risk of incident atrial fibrillation: The Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

Whether endogenous testosterone concentrations are associated with atrial fibrillation (AF) development is not well established. We assessed the association between plasma total testosterone concentrations and incident AF in a population-based longitudinal study.

STUDY DESIGN

Using data from the prospective Atherosclerosis Risk in Communities (ARIC) study, we identified incident AF among 9282 participants who had plasma total testosterone measured by liquid chromatography tandem mass spectrometry at Visit 4 (1996-1998).

MAIN OUTCOME MEASURES

AF cases were identified by electrocardiograms performed during study visits, hospital records/discharge codes, and death certificates through 2013. We estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) for incident AF across quartiles of plasma total testosterone, stratified by sex, with multivariable Cox models.

RESULTS

The mean age of the participant sample at ARIC Visit 4 was 63 years (range 52-75); 54.5% were women. Mean (SD) plasma total testosterone levels were 537 ng/dL (213) for men and 27.6 ng/dL (34.7) for women. Over a mean of 13.7 years of follow-up, 1664 incident cases of AF were identified. Comparing those in the highest quartile of plasma total testosterone concentration to those in the lowest quartile and after adjustment for potential confounding variables, there was a positive association between plasma total testosterone and incident AF in men (HR 1.33, 95% CI 1.07, 1.66), but no such association in women (HR 0.99, 95% CI 0.80, 1.22). Conclusion A higher plasma total testosterone concentration was associated with a modestly greater incidence rate of AF in men.

Cardiovascular Implications of the Menopause Transition: Endogenous Sex Hormones and Vasomotor Symptoms

The menopause transition (MT) is a critical period of women's lives marked by several physiologic changes and menopause-related symptoms that have implications for health. Risk for cardiovascular disease, the leading cause of death in women, increases after menopause, suggesting a contribution of the MT to its development. This article focuses on the relationship between 2 main features of the MT and women's cardiovascular health: (1) dynamic alterations of sex hormones, particularly endogenous estradiol and follicle-stimulating hormone, and (2) vasomotor symptoms, the cardinal symptom of the menopause. Limitations and future directions are discussed.

Sex Differences in Long-Term Clinical Outcomes in Patients With Atrial Fibrillation Undergoing Coronary Stent Implantation

BACKGROUND

Patients with concomitant atrial fibrillation (AF) and coronary stenting are at high risk for both cardiovascular and bleeding events. We aimed to evaluate the influence of sex on long-term clinical outcomes in this patient subset.Methods and Results:We identified 1,450 patients with AF and coronary stenting in a patient-level pooled database from 3 Japanese studies, and compared 3-year clinical outcomes between men and women (n=1,075, and n=375, respectively). The cumulative 3-year incidence of all-cause death was significantly higher in women than in men (26.5% vs. 17.2%, log-rank P<0.001), although after adjusting for confounders, the excess mortality risk of women relative to men was no longer significant (hazard ratio (HR): 1.12, 95% confidence interval (CI): 0.85-1.46, P=0.42). There were no significant differences in the adjusted 3-year risks for myocardial infarction or stroke between men and women (HR: 1.25, 95% CI: 0.62-2.40, P=0.52, and HR: 1.15, 95% CI: 0.75-1.74, P=0.52, respectively). However, both the cumulative 3-year incidence of and adjusted risk for major bleeding were significantly higher in women than in men (17.0% vs. 11.3%, log-rank P=0.002, and HR: 1.47, 95% CI: 1.03-2.07, P=0.03).

CONCLUSIONS

Among patients with concomitant AF and coronary stenting, there were no significant differences in the adjusted 3-year risks for all-cause death, myocardial infarction, and stroke between men and women. However, women as compared with men were associated with excess adjusted risk for major bleeding.

Serum androgens and risk of atrial fibrillation in older men: The Cardiovascular Health Study

BACKGROUND

Decline in serum androgens is common among older men and has been associated with cardiovascular disease, although its role in risk of atrial fibrillation (AF) has not been well defined.

HYPOTHESIS

Low serum androgens are associated with an increased risk of AF.

METHODS

We examined the prospective associations between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) with risk of AF among 1019 otherwise healthy men with average age 76.3 ±4.9 years in the Cardiovascular Health Study.

RESULTS

After median follow-up of 9.5 years, 304 (30%) men developed AF. We detected a nonlinear association with risk of incident AF in both free and total DHT, in which subjects with the lowest levels had a higher risk of incident AF. After adjustment for demographics, clinical risk factors, left atrial diameter, and serum NT-proBNP levels, men with free DHT <0.16 ng/dL were at increased risk compared with men with higher levels (hazard ratio: 1.48, 95% confidence interval: 1.01-2.17, P <0.05). Sensitivity analyses confirmed that the increased risk was not cutpoint-specific, with a significant association noted up to cutpoints <~0.2 ng/dL. We also detected a complex nonlinear association between SHBG and incident AF, in which subjects in the middle quintile (52.9-65.3 nmol/L) had increased risk.

CONCLUSIONS

Among older men, low free DHT is associated with an increased risk of incident AF. Further studies are needed to explore mechanisms for this association.

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.