Wilms' tumor 1 (WT1) antigen is overexpressed in Kaposi Sarcoma and is regulated by KSHV vFLIP.

In people living with HIV, Kaposi Sarcoma (KS), a vascular neoplasm caused by KS herpesvirus (KSHV/HHV-8), remains one of the most common malignancies worldwide. Individuals living with HIV, receiving otherwise effective antiretroviral therapy, may present with extensive disease requiring chemotherapy. Hence, new therapeutic approaches are needed. The Wilms' tumor 1 (WT1) protein is overexpressed and associated with poor prognosis in several hematologic and solid malignancies and has shown promise as an immunotherapeutic target. We found that WT1 was overexpressed in >90% of a total 333 KS biopsies, as determined by immunohistochemistry and image analysis. Our largest cohort from ACTG, consisting of 294 cases was further analyzed demonstrating higher WT1 expression was associated with more advanced histopathologic subtypes. There was a positive correlation between the proportion of infected cells within KS tissues, assessed by expression of the KSHV-encoded latency-associated nuclear antigen (LANA), and WT1 positivity. Areas with high WT1 expression showed sparse T-cell infiltrates, consistent with an immune evasive tumor microenvironment. We show that major oncogenic isoforms of WT1 are overexpressed in primary KS tissue and observed WT1 upregulation upon de novo infection of endothelial cells with KSHV. KSHV latent viral FLICE-inhibitory protein (vFLIP) upregulated total and major isoforms of WT1, but upregulation was not seen after expression of mutant vFLIP that is unable to bind IKKÆ´ and induce NFκB. siRNA targeting of WT1 in latent KSHV infection resulted in decreased total cell number and pAKT, BCL2 and LANA protein expression. Finally, we show that ESK-1, a T cell receptor-like monoclonal antibody that recognizes WT1 peptides presented on MHC HLA-A0201, demonstrates increased binding to endothelial cells after KSHV infection or induction of vFLIP expression. We propose that oncogenic isoforms of WT1 are upregulated by KSHV to promote tumorigenesis and immunotherapy directed against WT1 may be an approach for KS treatment.

Pooling Different Placebos as a Control Group in a Randomized Platform Trial: Benefits and Challenges From Experience in the ACTIV-2 COVID-19 Trial.

Adaptive platform trials were implemented during the coronavirus disease 2019 (COVID-19) pandemic to rapidly evaluate therapeutics, including the placebo-controlled phase 2/3 ACTIV-2 trial, which studied 7 investigational agents with diverse routes of administration. For each agent, safety and efficacy outcomes were compared to a pooled placebo control group, which included participants who received a placebo for that agent or for other agents in concurrent evaluation. A 2-step randomization framework was implemented to facilitate this. Over the study duration, the pooled placebo design achieved a reduction in sample size of 6% versus a trial involving distinct placebo control groups for evaluating each agent. However, a 26% reduction was achieved during the period when multiple agents were in parallel phase 2 evaluation. We discuss some of the complexities implementing the pooled placebo design versus a design involving nonoverlapping control groups, with the aim of informing the design of future platform trials. Clinical Trials Registration. NCT04518410.

Long COVID After Bamlanivimab Treatment.

BACKGROUND: Prospective evaluations of long COVID in outpatients with coronavirus disease 2019 (COVID-19) are lacking. We aimed to determine the frequency and predictors of long COVID after treatment with the monoclonal antibody bamlanivimab in ACTIV-2/A5401. METHODS: Data were analyzed from participants who received bamlanivimab 700 mg in ACTIV-2 from October 2020 to February 2021. Long COVID was defined as the presence of self-assessed COVID symptoms at week 24. Self-assessed return to pre-COVID health was also examined. Associations were assessed by regression models. RESULTS: Among 506 participants, median age was 51 years. Half were female, 5% Black/African American, and 36% Hispanic/Latino. At 24 weeks, 18% reported long COVID and 15% had not returned to pre-COVID health. Smoking (adjusted risk ratio [aRR], 2.41 [95% confidence interval {CI}, 1.34- 4.32]), female sex (aRR, 1.91 [95% CI, 1.28-2.85]), non-Hispanic ethnicity (aRR, 1.92 [95% CI, 1.19-3.13]), and presence of symptoms 22-28 days posttreatment (aRR, 2.70 [95% CI, 1.63-4.46]) were associated with long COVID, but nasal severe acute respiratory syndrome coronavirus 2 RNA was not. CONCLUSIONS: Long COVID occurred despite early, effective monoclonal antibody therapy and was associated with smoking, female sex, and non-Hispanic ethnicity, but not viral burden. The strong association between symptoms 22-28 days after treatment and long COVID suggests that processes of long COVID start early and may need early intervention. CLINICAL TRIALS REGISTRATION: NCT04518410.

Statistical Challenges When Analyzing SARS-CoV-2 RNA Measurements Below the Assay Limit of Quantification in COVID-19 Clinical Trials.

Most clinical trials evaluating coronavirus disease 2019 (COVID-19) therapeutics include assessments of antiviral activity. In recently completed outpatient trials, changes in nasal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA levels from baseline were commonly assessed using analysis of covariance (ANCOVA) or mixed models for repeated measures (MMRM) with single imputation for results below assay lower limits of quantification (LLoQ). Analyzing changes in viral RNA levels with singly imputed values can lead to biased estimates of treatment effects. In this article, using an illustrative example from the ACTIV-2 trial, we highlight potential pitfalls of imputation when using ANCOVA or MMRM methods, and illustrate how these methods can be used when considering values

Statistical Estimation of the Reproductive Number From Case Notification Data.

The reproductive number, or reproduction number, is a valuable metric in understanding infectious disease dynamics. There is a large body of literature related to its use and estimation. In the last 15 years, there has been tremendous progress in statistically estimating this number using case notification data. These approaches are appealing because they are relevant in an ongoing outbreak (e.g., for assessing the effectiveness of interventions) and do not require substantial modeling expertise to be implemented. In this article, we describe these methods and the extensions that have been developed. We provide insight into the distinct interpretations of the estimators proposed and provide real data examples to illustrate how they are implemented. Finally, we conclude with a discussion of available software and opportunities for future development.

Treatment of advanced AIDS-associated Kaposi sarcoma in resource-limited settings: a three-arm, open-label, randomised, non-inferiority trial.

BACKGROUND: Optimal treatment regimens for AIDS-associated Kaposi sarcoma, a frequent contributor to morbidity and mortality among people with HIV, have not been systematically evaluated in low-income and middle-income countries, where the disease is most common. In this study, we aimed to investigate optimal treatment strategies for advanced stage disease in areas of high prevalence and limited resources. METHODS: In this open-label, non-inferiority trial, we enrolled people with HIV and advanced stage AIDS-associated Kaposi sarcoma attending 11 AIDS Clinical Trials Group sites in Brazil, Kenya, Malawi, South Africa, Uganda, and Zimbabwe. Eligible participants were randomly assigned (1:1:1) with a centralised computer system to receive either intravenous bleomycin and vincristine or oral etoposide (the investigational arms), or intravenous paclitaxel (the control arm), together with antiretroviral therapy (ART; combined efavirenz, tenofovir disoproxil fumarate, and emtricitabine). The primary outcome was progression-free survival (PFS) at week 48, using a 15% non-inferiority margin to compare the investigational groups against the active control group. Safety was assessed in all eligible treated study participants. The study was registered with ClinicalTrials.gov, NCT01435018. FINDINGS: 334 participants were enrolled between Oct 1, 2013, and March 8, 2018, when the study was closed early due to inferiority of the bleomycin and vincristine plus ART arm, as per the recommendations of the Data and Safety Monitoring Board (DSMB). The etoposide plus ART arm also closed due to inferiority in March, 2016, following a DSMB recommendation. Week-48 PFS rates were higher in the paclitaxel plus ART arm than in both investigational arms. The absolute differences in PFS were -30% (95% CI -52 to -8) for the comparison of paclitaxel plus ART (week 48 PFS 50%, 32 to 67; n=59) and etoposide plus ART (20%, 6 to 33; n=59), and -20% (-33% to -7%) for the comparison of paclitaxel plus ART (64%, 55 to 73; n=138) and bleomycin and vincristine plus ART (44%, 35 to 53; n=132). Both CIs overlapped the non-inferiority margin. The most common adverse events, in 329 eligible participants who began treatment, were neutropenia (48 [15%]), low serum albumin (33 [10%]), weight loss (29 [9%]), and anaemia (28 [9%]), occurring at similar frequency across treatment arms. INTERPRETATION: Non-inferiority of either investigational intervention was not shown, with paclitaxel plus ART showing superiority to both oral etoposide plus ART and bleomycin and vincristine plus ART, supporting its use in treating advanced AIDS-associated Kaposi sarcoma in resource-limited settings. FUNDING: US National Institute of Allergy and Infectious Diseases and National Cancer Institute, National Institutes of Health.

Soluble Urokinase Plasminogen Activator Receptor Is Predictive of Non-AIDS Events During Antiretroviral Therapy-mediated Viral Suppression.

BACKGROUND: Despite effective antiretroviral therapy (ART), human immunodeficiency virus (HIV) infection remains associated with higher morbidity and mortality, driven, in part, by increased inflammation. Our objective was to identify associations between levels of plasma biomarkers of chronic inflammation, microbial translocation, and monocyte activation, with occurrence of non-AIDS events. METHODS: Participants (141 cases, 310 matched controls) were selected from a longitudinal observational trial; all were virally suppressed on ART at year 1 and thereafter. Soluble urokinase plasminogen activator receptor (suPAR), lipopolysaccharide binding protein (LBP), beta-D-glucan (BDG), intestinal fatty-acid binding protein, oxidized low-density lipoproteins, and soluble CD163 were measured pre-ART, after 1-year of ART, and pre-event. At each time point, conditional logistic regression analysis assessed associations of the biomarkers with events and adjusted for relevant covariates to calculate odds ratios (ORs) according to 1 interquartile range (IQR) difference. RESULTS: At all time points, higher levels of suPAR were associated with increased risk of non-AIDS events (OR per 1 IQR was 1.7 before ART-initiation, OR per 1 IQR was 2.0 after 1 year of suppressive ART, and OR 2.1 pre-event). Higher levels of BDG and LBP at year 1 and pre-event (but not at baseline) were associated with increased risk of non-AIDS events. No associations were observed for other biomarkers. CONCLUSIONS: Elevated levels of suPAR were strongly, consistently, and independently predictive of non-AIDS events at every measured time point. Interventions that target the suPAR pathway should be investigated to explore its role in the pathogenesis of non-AIDS-related outcomes in HIV infection.

Dolutegravir Plus Lamivudine Maintains Human Immunodeficiency Virus-1 Suppression Through Week 48 in a Pilot Randomized Trial.

Clinical Trials Registration: NCT02263326.

B-type natriuretic peptide and C-reactive protein in the prediction of atrial fibrillation risk: the CHARGE-AF Consortium of community-based cohort studies.

AIMS: B-type natriuretic peptide (BNP) and C-reactive protein (CRP) predict atrial fibrillation (AF) risk. However, their risk stratification abilities in the broad community remain uncertain. We sought to improve risk stratification for AF using biomarker information. METHODS AND RESULTS: We ascertained AF incidence in 18 556 Whites and African Americans from the Atherosclerosis Risk in Communities Study (ARIC, n=10 675), Cardiovascular Health Study (CHS, n = 5043), and Framingham Heart Study (FHS, n = 2838), followed for 5 years (prediction horizon). We added BNP (ARIC/CHS: N-terminal pro-B-type natriuretic peptide; FHS: BNP), CRP, or both to a previously reported AF risk score, and assessed model calibration and predictive ability [C-statistic, integrated discrimination improvement (IDI), and net reclassification improvement (NRI)]. We replicated models in two independent European cohorts: Age, Gene/Environment Susceptibility Reykjavik Study (AGES), n = 4467; Rotterdam Study (RS), n = 3203. B-type natriuretic peptide and CRP were significantly associated with AF incidence (n = 1186): hazard ratio per 1-SD ln-transformed biomarker 1.66 [95% confidence interval (CI), 1.56-1.76], P < 0.0001 and 1.18 (95% CI, 1.11-1.25), P < 0.0001, respectively. Model calibration was sufficient (BNP, χ(2) = 17.0; CRP, χ(2) = 10.5; BNP and CRP, χ(2) = 13.1). B-type natriuretic peptide improved the C-statistic from 0.765 to 0.790, yielded an IDI of 0.027 (95% CI, 0.022-0.032), a relative IDI of 41.5%, and a continuous NRI of 0.389 (95% CI, 0.322-0.455). The predictive ability of CRP was limited (C-statistic increment 0.003). B-type natriuretic peptide consistently improved prediction in AGES and RS. CONCLUSION: B-type natriuretic peptide, not CRP, substantially improved AF risk prediction beyond clinical factors in an independently replicated, heterogeneous population. B-type natriuretic peptide may serve as a benchmark to evaluate novel putative AF risk biomarkers.

Machine learning models based on fluid immunoproteins that predict non-AIDS adverse events in people with HIV.

Despite the success of antiretroviral therapy (ART), individuals with HIV remain at risk for experiencing non-AIDS adverse events (NAEs), including cardiovascular complications and malignancy. Several surrogate immune biomarkers in blood have shown predictive value in predicting NAEs; however, composite panels generated using machine learning may provide a more accurate advancement for monitoring and discriminating NAEs. In a nested case-control study, we aimed to develop machine learning models to discriminate cases (experienced an event) and matched controls using demographic and clinical characteristics alongside 49 plasma immunoproteins measured prior to and post-ART initiation. We generated support vector machine (SVM) classifier models for high-accuracy discrimination of individuals aged 30-50 years who experienced non-fatal NAEs at pre-ART and one-year post-ART. Extreme gradient boosting generated a high-accuracy model at pre-ART, while K-nearest neighbors performed poorly all around. SVM modeling may offer guidance to improve disease monitoring and elucidate potential therapeutic interventions.

Safety, Efficacy, and Pharmacokinetics of Combination SARS-CoV-2 Neutralizing Monoclonal Antibodies BMS-986414 (C135-LS) and BMS-986413 (C144-LS) Administered Subcutaneously in Non-Hospitalized Persons with COVID-19 in a Phase 2 Trial.

Background: Outpatient COVID-19 monoclonal antibody (mAb) treatment via subcutaneous delivery, if effective, overcomes the logistical burdens of intravenous administration. Methods: ACTIV-2/A5401 was a randomized, masked placebo-controlled platform trial where participants with COVID-19 at low risk for progression were randomized 1:1 to subcutaneously administered BMS-986414 (C135-LS) 200 mg, plus BMS-986413 (C144-LS) 200 mg, (BMS mAbs), or placebo. Coprimary outcomes were time to symptom improvement through 28 days; nasopharyngeal SARS-CoV-2 RNA below the lower limit of quantification (LLoQ) on days 3, 7, or 14; and treatment-emergent grade 3 or higher adverse events (TEAEs) through 28 days. Results: A total of 211 participants (105 BMS mAbs and 106 placebo) initiated study product. Time to symptom improvement favored the active therapy but was not significant (median 8 vs 10 days, P=0.19). There was no significant difference in the proportion with SARS-CoV-2 RNA

Statistical Challenges when Analyzing SARS-CoV-2 RNA Measurements Below the Assay Limit of Quantification in COVID-19 Clinical Trials.

Most clinical trials evaluating COVID-19 therapeutics include assessments of antiviral activity. In recently completed outpatient trials, changes in nasal SARS-CoV-2 RNA levels from baseline were commonly assessed using analysis of covariance (ANCOVA) or mixed models for repeated measures (MMRM) with single-imputation for results below assay lower limits of quantification (LLoQ). Analyzing changes in viral RNA levels with singly-imputed values can lead to biased estimates of treatment effects. In this paper, using an illustrative example from the ACTIV-2 trial, we highlight potential pitfalls of imputation when using ANCOVA or MMRM methods, and illustrate how these methods can be used when considering values

Age of natural menopause and atrial fibrillation: the Framingham Heart Study.

BACKGROUND: Early menopausal age is associated with risk of cardiovascular events including myocardial infraction, stroke, and increased mortality. Relations between menopausal age and atrial fibrillation (AF) have not been investigated. We examined the association between menopausal age and AF. METHODS: Framingham Heart Study women ≥ 60 years old without prevalent AF and natural menopause were followed up for 10 years or until incident AF. Menopausal age was modeled as a continuous variable and by categories (<45, 45-53, and >53 years). We used Cox proportional hazards regression to determine associations between menopausal age and AF risk. RESULTS: In 1,809 Framingham women (2,662 person-examinations, mean baseline age 71.4 ± 7.6 years, menopausal age 49.8 ± 3.6 years), there were 273 unique participants with incident AF. We did not identify a significant association between the SD of menopausal age (3.6 years) and AF (hazard ratio [HR] per SD 0.94, 95% CI 0.83-1.06; P = .29). In a multivariable model with established risk factors for AF, menopausal age was not associated with incident AF (HR per SD 0.97, 95% CI 0.86-1.09; P = .60). Examining categorical menopausal age, earlier menopausal age (<45 years) was not significantly associated with increased AF risk compared with older menopausal age >53 years (HR 1.20, 95% CI 0.74-1.94; P = .52) or menopausal age 45 to 53 years (HR 1.38, 95% CI 0.93-2.04; P = .11). CONCLUSION: In our moderate-sized, community-based sample, we did not identify menopausal age as significantly increasing AF risk. However, future larger studies will need to examine whether there is a small effect of menopausal age on AF risk.

Monitoring Circulating Immune Checkpoint Proteins as Predictors of Non-AIDS Morbid Events in People With HIV Initiating Antiretroviral Therapy.

BACKGROUND: Although cell surface immune checkpoint proteins (ICPs) such as PD-1 expressed on T cells are associated with T-cell exhaustion, HIV disease progression, and AIDS events, they have shown limited utility in predicting non-AIDS morbidity. Given that ICPs also exist in soluble forms and are elevated in ART-treated HIV infection, we tested the hypothesis that soluble ICPs may be predictive of non-AIDS events in adults initiating ART. METHODS: Utilizing a nested case-control study from the AIDS Clinical Trials Group ALLRT cohort, we measured plasma levels of 15 soluble inhibitory and activating ICPs by Luminex. Participants (134 cases, 292 matched controls) were evaluated pre-ART, a year post-ART, and immediately preceding a non-AIDS event, which included myocardial infarction (MI)/stroke, malignancy, serious bacterial infection, and nonaccidental death. RESULTS: Conditional logistic regression analysis determined that higher levels of soluble CD27 were associated with increased risk of non-AIDS events at all time points. Higher levels of CD40 at baseline and pre-event and CD80 at pre-event were associated with increased risk of non-AIDS events. Examining specific non-AIDS events, multiple ICPs were associated with malignancy at baseline and pre-event, whereas only higher CD27 levels were associated with increased risk of MI/stroke at year 1 and pre-event. CONCLUSIONS: While select soluble ICPs were associated with non-AIDS events, CD27 emerged as a consistent marker irrespective of ART. Our data may offer guidance on new targets for early clinical monitoring in people with HIV who remain at greater risk of specific non-AIDS events.

Plasma galectin-9 as a predictor of adverse non-AIDS events in persons with chronic HIV during suppressive antiretroviral therapy.

BACKGROUND: People with HIV (PWH) on antiretroviral therapy (ART) still experience an increased risk of morbidity and mortality, presumably driven by chronic inflammation, yet predictors of discrete or combinatorial outcomes remain unclear. Galectin-9 (Gal-9), a driver of both inflammatory and immunosuppressive responses, has been associated with HIV disease progression and multimorbidity. OBJECTIVE: To determine whether plasma Gal-9 levels are associated with the occurrence of specific non-AIDS events (NAEs) in PWH initiating ART. DESIGN: We performed a nested case-control study of PWH enrolled from 2001 to 2009 and evaluated pre-ART (66 cases, 97 controls), a year post-ART (112 cases, 211 controls), and immediately preceding an event (89 cases, 162 controls). Events included myocardial infarction/stroke, malignancy, serious bacterial infection, or death. METHODS: Plasma Gal-9 levels were assessed by ELISA. Conditional logistic regression assessed associations with NAEs and Spearman's correlations compared Gal-9 with other previously assessed biomarkers. RESULTS: NAEs occurred at a median of 2.8 years (1.7-4.6) after ART initiation. Higher Gal-9 levels were associated with increased risk of NAEs at year 1 and preevent [odds ratio (OR) per 1 interquartile range = 1.4-1.6; all P < 0.05], specifically myocardial infarction/stroke at year 1 (OR = 1.9; P = 0.029). Gal-9 also correlated with multiple inflammatory and immune activation predictors of NAEs (all timepoints). CONCLUSION: Elevated Gal-9 levels are predictive of deleterious NAEs, particularly cardiovascular complications. Whether the Gal-9 pathway, potentially binding to its putative ligands, is active in the pathogenesis of these outcomes warrants further investigation to determine if targeting Gal-9 may slow or reverse the risk of NAEs.

Estimating age-specific reproductive numbers-A comparison of methods.

Large outbreaks, such as those caused by influenza, put a strain on resources necessary for their control. In particular, children have been shown to play a key role in influenza transmission during recent outbreaks, and targeted interventions, such as school closures, could positively impact the course of emerging epidemics. As an outbreak is unfolding, it is important to be able to estimate reproductive numbers that incorporate this heterogeneity and to use surveillance data that is routinely collected to more effectively target interventions and obtain an accurate understanding of transmission dynamics. There are a growing number of methods that estimate age-group specific reproductive numbers with limited data that build on methods assuming a homogenously mixing population. In this article, we introduce a new approach that is flexible and improves on many aspects of existing methods. We apply this method to influenza data from two outbreaks, the 2009 H1N1 outbreaks in South Africa and Japan, to estimate age-group specific reproductive numbers and compare it to three other methods that also use existing data from social mixing surveys to quantify contact rates among different age groups. In this exercise, all estimates of the reproductive numbers for children exceeded the critical threshold of one and in most cases exceeded those of adults. We introduce a flexible new method to estimate reproductive numbers that describe heterogeneity in the population.

Brief Report: Changes in Plasma RANKL-Osteoprotegerin in a Prospective, Randomized Clinical Trial of Initial Antiviral Therapy: A5260s.

BACKGROUND: The contributions of the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) axis to cardiovascular and bone disease in treated HIV-1 infection are not well defined. SETTING: Prospective, observational, longitudinal study. METHODS: In a subset analysis of a prospective randomized clinical trial, 234 HIV-1-infected antiretroviral therapy-naive participants received tenofovir-emtricitabine plus either atazanavir/ritonavir, darunavir/ritonavir, or raltegravir and achieved plasma HIV-1 RNA <50 copies per milliliter by week 24 and thereafter. Associations between plasma RANKL, OPG, or RANKL/OPG ratio levels with total, hip, and spine bone mineral density (BMD) loss or progression of carotid artery intima-media thickness were assessed longitudinally over 96 weeks. RESULTS: Over 96 weeks, all treatment groups had similar and sustained declines in plasma RANKL, increases in plasma OPG, and subsequently, decreases in the RANKL/OPG ratio. There were no associations between plasma RANKL or RANKL/OPG ratio levels with total, hip, and spine BMD loss or progression of carotid artery intima-media thickness; however, plasma OPG in successfully treated HIV-infected patients (week 48 and 96) was associated with spine BMD loss. CONCLUSIONS: In virologically suppressed HIV-infected patients, the evolution of bone disease could be linked to plasma OPG levels; however, the role of plasma levels of RANKL and RANKL/OPG ratio in the prediction of morbidity in treated HIV-1 infection may be limited.

The impact of prior information on estimates of disease transmissibility using Bayesian tools.

The basic reproductive number (R0) and the distribution of the serial interval (SI) are often used to quantify transmission during an infectious disease outbreak. In this paper, we present estimates of R0 and SI from the 2003 SARS outbreak in Hong Kong and Singapore, and the 2009 pandemic influenza A(H1N1) outbreak in South Africa using methods that expand upon an existing Bayesian framework. This expanded framework allows for the incorporation of additional information, such as contact tracing or household data, through prior distributions. The results for the R0 and the SI from the influenza outbreak in South Africa were similar regardless of the prior information (R0 = 1.36-1.46, µ = 2.0-2.7, µ = mean of the SI). The estimates of R0 and µ for the SARS outbreak ranged from 2.0-4.4 and 7.4-11.3, respectively, and were shown to vary depending on the use of contact tracing data. The impact of the contact tracing data was likely due to the small number of SARS cases relative to the size of the contact tracing sample.

Association of sex hormones, aging, and atrial fibrillation in men: the Framingham Heart Study.

BACKGROUND: Endogenous sex hormones have been related to cardiovascular outcomes and mortality. We hypothesized that sex hormones are related to atrial fibrillation (AF) in a community-based cohort of middle-aged to older men. METHODS AND RESULTS: We examined testosterone, estradiol, and dehydroepiandrosterone sulfate in relation to incident AF in men participating in the Framingham Heart Study. We assessed the 10-year risk of AF in multivariable-adjusted hazard models. The cohort consisted of 1251 men (age, 68.0±8.2 years), of whom 275 developed incident AF. We identified a significant interaction between age and testosterone and, therefore, stratified men into age 55 to 69 years (n=786), 70 to 79 years (n=351), and ≥80 years (n=114). In men aged 55 to 69 years, each 1 SD decrease in testosterone was associated with hazard ratio (HR) 1.30 (95% confidence interval [CI], 1.07-1.59) for incident AF. The association between testosterone and 10-year incident AF in men 70 to 79 years did not reach statistical significance. In men≥80 years, a 1 SD decrease in testosterone was associated with HR 3.53 (95% CI, 1.96-6.37) for AF risk. Estradiol was associated with incident AF (HR, 1.12; 95% CI, 1.01-1.26). Dehydroepiandrosterone sulfate had a borderline association with risk of AF that was not statistically significant (HR, 1.12; 95% CI, 0.99-1.28). CONCLUSIONS: Testosterone and estradiol are associated with incident AF in a cohort of older men. Testosterone deficiency in men≥80 years is strongly associated with AF risk. The clinical and electrophysiological mechanisms underlying the associations between sex hormones and AF in older men merit continued investigation.