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Aims: To identify robust circulating predictors for incident atrial fibrillation (AF) using classical regressions and machine learning (ML) techniques within a broad spectrum of candidate variables., Methods and Results: In pooled European community cohorts (n = 42 280 individuals), 14 routinely available biomarkers mirroring distinct pathophysiological pathways including lipids, inflammation, renal, and myocardium-specific markers (N-terminal pro B-type natriuretic peptide [NT-proBNP], high-sensitivity troponin I [hsTnI]) were examined in relation to incident AF using Cox regressions and distinct ML methods. Of 42 280 individuals (21 843 women [51.7%]; median [interquartile range, IQR] age, 52.2 [42.7, 62.0] years), 1496 (3.5%) developed AF during a median follow-up time of 5.7 years. In multivariable-adjusted Cox-regression analysis, NT-proBNP was the strongest circulating predictor of incident AF [hazard ratio (HR) per standard deviation (SD), 1.93 (95% CI, 1.82-2.04); P < 0.001]. Further, hsTnI [HR per SD, 1.18 (95% CI, 1.13-1.22); P < 0.001], cystatin C [HR per SD, 1.16 (95% CI, 1.10-1.23); P < 0.001], and C-reactive protein [HR per SD, 1.08 (95% CI, 1.02-1.14); P = 0.012] correlated positively with incident AF. Applying various ML techniques, a high inter-method consistency of selected candidate variables was observed. NT-proBNP was identified as the blood-based marker with the highest predictive value for incident AF. Relevant clinical predictors were age, the use of antihypertensive medication, and body mass index., Conclusion: Using different variable selection procedures including ML methods, NT-proBNP consistently remained the strongest blood-based predictor of incident AF and ranked before classical cardiovascular risk factors. The clinical benefit of these findings for identifying at-risk individuals for targeted AF screening needs to be elucidated and tested prospectively., Competing Interests: Conflict of interest: R.B.S. has received lecture fees and advisory board fees from BMS/Pfizer outside the submitted work. B.T. receives project-related funding by the German Heart Foundation and Ernst und Berta Grimmke-Stiftung unrelated to the submitted work. V.S. reports an honorarium for consulting from Sanofi. He also has research collaboration with Bayer Ltd (all unrelated to the present study). T.N. reports speaker honoraria from Servier outside the submitted work. S.S. received honoraria from Actelion (now Janssen) outside the submitted work. Furthermore, S.S. is a member of the advisory board of Actelion (now Janssen) and of Novartis. I.K. has received research grants by the Heart Foundation in Northern Sweden and Arnerska Research Foundation, both unrelated to the present study. S.B. reports honoraria to his institution from Abbott, Bayer, Siemens, Singulex, and Roche, outside the submitted work. S.B. also reports personal fees from Abbott, Bayer, Siemens, Novartis, Thermo Fisher, Astra Zeneca, AMGEN, Medtronic, and Pfizer. S.Co. has received honoraria for lecturing from The Dutch Beer Institute foundation—The Brewers of Europe, outside the submitted work. S.Co. and A.D.C. are the PI and Co-PI, respectively, of a research grant from ERAB (the European Foundation for Alcohol Research, EA 1767, completed in January 2020), which is unrelated to the present study. G.d.G. is a member of the International Scientific Forum on Alcohol Research. The members of the Forum receive no financial support. The Forum itself receives no support from any other organization or company in the alcoholic beverage industry. G.d.G. was also a consultant to the Web Newsletter of Assobirra, the Italian Association of the Beer and Malt Industries and is a corresponding member of the non-profit Accademia Italiana della Vite e del Vino. G.d.G. reports personal fees for given lectures at the 8th European Beer and Health Symposium (2017), Beer and Health Initiative (The Dutch Beer Institute Foundation—The Brewers of Europe), outside the submitted work. All remaining authors have declared no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: To explore sex-specific time trends in atrial fibrillation (AF) incidence and to estimate the impact of changes in risk factor levels using individual participant-level data from the population-based Tromsø Study 1994-2016., Methods and Results: A total of 14 818 women and 13 225 men aged 25 years or older without AF were enrolled in the Tromsø Study between 1994 and 2008 and followed up for incident AF throughout 2016. Poisson regression was used for statistical analyses. During follow-up, age-adjusted AF incidence rates in women decreased from 1.19 to 0.71 per 1000 person-years. In men, AF incidence increased from 1.18 to 2.82 per 1000 person-years in 2004, and then declined to 1.94 per 1000 person-years in 2016. Changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP), body mass index (BMI), physical activity, smoking and alcohol consumption together accounted for 10.9% [95% confidence interval (CI): -2.4 to 28.6] of the AF incidence decline in women and for 44.7% (95% CI: 19.2; 100.0) of the AF incidence increase in men. Reduction in SBP and DBP had the largest contribution to the decrease in AF incidence in women. Increase in BMI had the largest contribution to the increase in AF incidence in men., Conclusion: In the population-based Tromsø Study 1994-2016, AF incidence decreased in women and increased following a reverse U-shape in men. Individual changes in SBP and DBP in women and individual changes in BMI in men were the most important risk factors contributing to the AF incidence trends., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background Although myocardial infarction (MI) and atrial fibrillation (AF) are frequent comorbidities and share common cardiovascular risk factors, the direction and strength of the association of the risk factors with disease onset, subsequent disease incidence, and mortality are not completely understood. Methods and Results In pooled multivariable Cox regression analyses, we examined temporal relations of disease onset and identified predictors of MI, AF, and all-cause mortality in 108 363 individuals (median age, 46.0 years; 48.2% men) free of MI and AF at baseline from 6 European population-based cohorts. During a maximum follow-up of 10.0 years, 3558 (3.3%) individuals were diagnosed exclusively with MI, 1922 (1.8%) with AF but no MI, and 491 (0.5%) individuals developed both MI and AF. Association of sex, systolic blood pressure, antihypertensive treatment, and diabetes appeared to be stronger with incident MI than with AF, whereas increasing age and body mass index showed a higher risk for incident AF. Total cholesterol and daily smoking were significantly related to incident MI but not AF. Combined population attributable fraction of cardiovascular risk factors was >70% for incident MI, whereas it was only 27% for AF. Subsequent MI after AF (hazard ratio [HR], 1.68; 95% CI, 1.03-2.74) and subsequent AF after MI (HR, 1.75; 95% CI, 1.31-2.34) both significantly increased overall mortality risk. Conclusions We observed different associations of cardiovascular risk factors with both diseases indicating distinct pathophysiological pathways. Subsequent diagnoses of MI and AF significantly increased mortality risk.

Background: The main aim was to examine age-specific risk factor associations with incident atrial fibrillation (AF) and their attributable fraction in a large European cohort. Additionally, we aimed to examine risk of stroke and mortality in relation to new-onset AF across age., Methods: We used individual-level data (n=66 951, 49.1% men, age range 40-98 years at baseline) from five European cohorts of the MOnica Risk, Genetics, Archiving and Monograph Consortium. The participants were followed for incident AF for up to 10 years and the association with modifiable risk factors from the baseline examinations (body mass index (BMI), hypertension, diabetes, daily smoking, alcohol consumption and history of stroke and myocardial infarction (MI)) was examined. Additionally, the participants were followed up for incident stroke and all-cause mortality after new-onset AF., Results: AF incidence increased from 0.9 per 1000 person-years at baseline age 40-49 years, to 17.7 at baseline age ≥70 years. Multivariable-adjusted Cox models showed that higher BMI, hypertension, high alcohol consumption and a history of stroke or MI were associated with increased risk of AF across age groups (p<0.05). Between 30% and 40% of the AF risk could be attributed to BMI, hypertension and a history of stroke or MI. New-onset AF was associated with a twofold increase in risk of stroke and death at ages≥70 years (p≤0.001)., Conclusion: In this large European cohort aged 40 years and above, risk of AF was largely attributed to BMI, high alcohol consumption and a history MI or stroke from middle age. Thus, preventive measures for AF should target risk factors such as obesity and hypertension from early age and continue throughout life., Competing Interests: Competing interests: RBS has received lecture fees and advisory board fees from BMS/Pfizer outside this work., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: There is inconsistent evidence on the relation of alcohol intake with incident atrial fibrillation (AF), in particular at lower doses. We assessed the association between alcohol consumption, biomarkers, and incident AF across the spectrum of alcohol intake in European cohorts., Methods and Results: In a community-based pooled cohort, we followed 107 845 individuals for the association between alcohol consumption, including types of alcohol and drinking patterns, and incident AF. We collected information on classical cardiovascular risk factors and incident heart failure (HF) and measured the biomarkers N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin I. The median age of individuals was 47.8 years, 48.3% were men. The median alcohol consumption was 3 g/day. N = 5854 individuals developed AF (median follow-up time: 13.9 years). In a sex- and cohort-stratified Cox regression analysis alcohol consumption was non-linearly and positively associated with incident AF. The hazard ratio for one drink (12 g) per day was 1.16, 95% CI 1.11-1.22, P < 0.001. Associations were similar across types of alcohol. In contrast, alcohol consumption at lower doses was associated with reduced risk of incident HF. The association between alcohol consumption and incident AF was neither fully explained by cardiac biomarker concentrations nor by the occurrence of HF., Conclusions: In contrast to other cardiovascular diseases such as HF, even modest habitual alcohol intake of 1.2 drinks/day was associated with an increased risk of AF, which needs to be considered in AF prevention., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: To explore sex-specific associations between long-term individual blood pressure (BP) patterns and risk of incident atrial fibrillation (AF) in the general population., Methods and Results: Blood pressure was measured in 8376 women and 7670 men who attended at least two of the three population-based Tromsø Study surveys conducted in 1986-87, 1994-95, and 2001. Participants were followed for incident AF throughout 2013. Latent mixed modelling was used to identify long-term trajectories of systolic BP and hypertension. Cox regression was used to estimate associations between the identified trajectories and incident AF. Elevated systolic BP throughout the exposure period (1986-2001) independently and differentially increased risk of AF in women and men. In women, having elevated systolic BP trajectories doubled AF risk compared to having persistently low levels, irrespective of whether systolic BP increased, decreased, or was persistently high over time, with hazard ratios of 1.88 (95% confidence interval 1.37-2.58), 2.32 (1.61-3.35), and 1.94 (1.28-2.94), respectively. In men, those with elevated systolic BP that continued to increase over time had a 50% increased AF risk: 1.51 (1.09-2.10). When compared to those persistently normotensive, women developing hypertension during the exposure period, and women and men with hypertension throughout the exposure period had 1.40 (1.06-1.86), 2.75 (1.99-3.80), and 1.36 (1.10-1.68) times increased risk of AF, respectively., Conclusion: Long-term BP and hypertension trajectories were associated with increased incidence of AF in both women and men, but the associations were stronger in women., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: Limited evidence is available on the temporal relationship between atrial fibrillation (AF) and ischaemic stroke and their impact on mortality in the community. We sought to understand the temporal relationship of AF and ischaemic stroke and to determine the sequence of disease onset in relation to mortality., Methods and Results: Across five prospective community cohorts of the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE) project we assessed baseline cardiovascular risk factors in 100 132 individuals, median age 46.1 (25th-75th percentile 35.8-57.5) years, 48.4% men. We followed them for incident ischaemic stroke and AF and determined the relation of subsequent disease diagnosis with overall mortality. Over a median follow-up of 16.1 years, N = 4555 individuals were diagnosed solely with AF, N = 2269 had an ischaemic stroke but no AF diagnosed, and N = 898 developed both, ischaemic stroke and AF. Temporal relationships showed a clustering of diagnosis of both diseases within the years around the diagnosis of the other disease. In multivariable-adjusted Cox regression analyses with time-dependent covariates subsequent diagnosis of AF after ischaemic stroke was associated with increased mortality [hazard ratio (HR) 4.05, 95% confidence interval (CI) 2.17-7.54; P < 0.001] which was also apparent when ischaemic stroke followed after the diagnosis of AF (HR 3.08, 95% CI 1.90-5.00; P < 0.001)., Conclusion: The temporal relations of ischaemic stroke and AF appear to be bidirectional. Ischaemic stroke may precede detection of AF by years. The subsequent diagnosis of both diseases significantly increases mortality risk. Future research needs to investigate the common underlying systemic disease processes., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: Atrial fibrillation (AF) prevalence is increasing, and body mass index (BMI) is a risk factor for AF. However, sex differences in the impact of BMI on AF risk have not been fully elucidated., Methods and Results: Data from the fourth survey (1994-1995) of the Tromsø Study (Norway) were used to investigate the association of single-measurement BMI on future AF risk. To analyze the influence of BMI changes on AF risk, data from individuals who attended the third and fourth study surveys were used. AF diagnosis was derived from record linkage and end point adjudication. Cox regression analysis was conducted using fractional polynomials of BMI and BMI change with models adjusted for age, baseline BMI (change analyses), risk factors, comorbidities, and antihypertensive medications.Data were available for 24 799 individuals from the fourth survey (mean age, 45.5±14.2 years; 52.9% women). Over 15.7±5.5 years, 811 women (6.2%) and 918 men (7.9%) developed AF. In men, lower BMI decreased AF risk and higher BMI increased risk (hazard ratios [95% confidence intervals] for BMI 18 or 40 kg/m 2 compared with 23 kg/m 2 were 0.75 [0.70-0.81] and 4.42 [3.00-6.53], respectively). The same pattern was identified in women. Two surveys were attended by 14 652 individuals. In men and women, a decrease in BMI over time was associated with decreased AF risk and an increase in BMI was associated with increased AF risk., Conclusions: Within a population cohort, BMI was positively associated with AF risk. Change in BMI over time influenced AF risk in both men and women., (© 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background: Atrial fibrillation (AF) is a well-established risk factor for ischemic stroke (IS). Emerging evidence also indicates an association between AF and pulmonary embolism (PE). Because IS may potentially mediate the observed risk of PE in AF, we aimed to assess the impact of AF on the cause-specific risks of PE and IS in a large cohort recruited from the general population., Methods and Results: We observed 29 842 participants from 3 surveys of the Tromsø study (inclusion in 1994-1995, 2001-2002, and 2007-2008) to the end of 2012. Incident events of AF, IS, and PE during follow-up were recorded, and information on potential confounders was obtained at baseline. Cox regression models, with AF as a time-dependent variable, were used to calculate cause-specific hazard ratios (HRs) with 95% confidence intervals (CIs) for PE and IS. There were 2067 participants diagnosed as having AF, 296 with PE and 1164 with IS, during a median of 17.6 years of follow-up. The risks of PE (HR, 10.88; 95% CI, 6.23-18.89) and IS (HR, 6.16; 95% CI, 4.47-8.48) were substantially increased during the first 6 months after AF diagnosis, with crude incidence rates of 18.5 per 1000 person-years for PE and 52.8 per 1000 person-years for IS. The risk estimates remained elevated for both PE (HR, 1.72; 95% CI, 1.10-2.71) and IS (HR, 2.45; 95% CI, 2.05-2.92) throughout the study period., Conclusions: AF was associated with increased cause-specific risks of both PE and IS. Our findings infer that the risk of PE in AF is not explained by intermediate IS., (© 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background Resting heart rate is an established risk factor for cardiovascular disease, but long-term individual resting heart rate trajectories and their effect on cardiovascular disease morbidity and mortality have not yet been described. Methods This large population-based longitudinal study included 14,208 men and women aged 20 years or older, not pregnant and not using blood pressure medications, who attended at least two of the three Tromsø Study surveys conducted between 1986-2001. Resting heart rate was measured using an automated Dinamap device. Participants were followed up from 2001 to 2012 with respect to myocardial infarction, atrial fibrillation, ischaemic stroke, cardiovascular disease death and total death. The Proc Traj statistical procedure was used to identify resting heart rate trajectories. Results Five common long-term resting heart rate trajectories were identified: low, moderate, decreasing, increasing and elevated. In men, an elevated resting heart rate trajectory was independently associated with an increased risk of myocardial infarction when low resting heart rate trajectory was used as a reference (hazard ratio 1.83, 95% confidence interval 1.11-3.02). Risk of total death in men was lowest in the low resting heart rate trajectory group and highest in the increasing and elevated resting heart rate trajectory groups. In women, the association between resting heart rate trajectories and myocardial infarction was similar to that in men, but it was not significant. Conclusions Among the five long-term resting heart rate trajectories we identified, increasing and elevated trajectories were associated with an increased risk of myocardial infarction and total death in men. Our results suggest that changes in long-term individual resting heart rate in the general population may provide additional prognostic information.

Background: Elevated resting heart rate (RHR) increases risk of death overall, but a comprehensive picture of the associations between RHR, cardiovascular morbidity and mortality events has not yet been presented. We aimed to investigate the effect of RHR on the risk of 5 cardiovascular events: incident myocardial infarction (MI), incident atrial fibrillation (AF), incident ischaemic stroke, total death and cardiovascular death in a general population from Norway., Methods: We followed 24 489 men and women from the Tromsø Study 1994-1995, a population-based cohort study, for 18 years, and analysed the association between RHR and the investigated cardiovascular events. Sex-specific Cox regression with time-dependent covariates was applied with the best-fitting fractional polynomials of RHR., Results: Among men, an independent positive relationship was observed for MI and AF (adjusted HR for AF per 20 bpm increase=1.14; 95% CI 1.02 to 1.27). In women, the corresponding HR for MI was 1.23 (1.09 to 1.40). A J-shaped association was observed for ischaemic stroke in women when compared with a RHR of 70 bpm (HR for 50 bpm=1.31; 0.90 to 1.90; HR for 100 bpm=1.32; 1.04 to 1.69). Total and cardiovascular death showed a strong positive association with RHR in men. In women, the pattern for total death was similar., Conclusions: RHR is an independent risk factor for several cardiovascular events. A novel finding is the positive association between RHR and AF in men and the sex difference in association with ischaemic stroke., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objective: To investigate the association between echocardiographic measurements with emphasis on diastolic dysfunction and risk of atrial fibrillation (AF) in a population-based cohort study., Methods: We followed 2406 participants from the Tromsø Study from 1994 to 2010. Left atrial (LA) size and mitral Doppler indices as measured by echocardiography were used for evaluating diastolic dysfunction. Information concerning age, systolic blood pressure, height, heart rate, body mass index, total and high-density lipoprotein cholesterol, self-reported use of alcohol, smoking, coffee, physical activity, antihypertensive treatment, prevalent coronary heart disease, valvular heart disease, heart failure, hypertrophy, diabetes and palpitations were obtained at baseline. The outcome measure was clinical AF, documented by an ECG., Results: AF was detected in 462 subjects (193 women). Mean age at baseline was 62.6 years. Incidence rate of clinical AF was 12.6 per 1000 person-years. In multivariable Cox proportional hazards regression analysis, moderately enlarged LA was associated with 60% (95% CI 1.2 to 2.0) increased risk of AF. Severely enlarged LA had HR for AF of 4.2 (95% CI 2.7 to 6.5) with p value for linear trend <0.001, and the association was similar in both sexes. Abnormal mitral Doppler flow adjusted for predictor variables did not show a statistically significant association with AF risk. However, when LA size was also adjusted for, the risk of AF increased by 30% (95% CI 1.0 to 1.6)., Conclusions: Our findings suggest that enlarged LA as a measure for diastolic dysfunction is a significant risk factor for AF in both sexes, and adding measures of abnormal diastolic flow increased the predictive ability significantly., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Aims: Serum uric acid (SUA) has been associated with cardiovascular disease in population studies, but its relation to atrial fibrillation (AF) is largely unknown. The aim of this study was to investigate the association between baseline SUA and future AF in a large population-based cohort., Methods and Results: A total of 6308 men and women from a population survey in Tromsø, Norway in 1994-95 were followed-up for 10.8 years. The mean age at baseline was 60 years. Information on angina, myocardial infarction, diabetes, anti-hypertensive and diuretic treatment, physical activity, smoking and alcohol, and measurements of height, weight, blood pressure, SUA, total cholesterol, and high density lipoprotein-cholesterol were obtained at baseline. The outcome measure was first-ever AF, documented on an electrocardiogram. We identified 572 cases of incident AF. In multivariable Cox proportional hazards regression analysis adjusted for cardiovascular risk factors and concomitant diseases, SUA was associated with AF in both sexes. Hazard ratio per 1 SD increase in SUA (91 μmol/L) was 1.40 [95% confidence intervals (CI), 1.14-1.72] in women and 1.17 (95% CI, 1.02-1.36) in men. The upper quartile of SUA conferred a 76% increased risk for AF in women and 49% in men as compared with the lowest quartile., Conclusion: This prospective population-based cohort study showed that baseline SUA was associated with an increased risk for future AF in both sexes.

Background: Pulmonary embolism (PE) may trigger atrial fibrillation through increased right atrial pressure and subsequent atrial strain, but the degree of evidence is low. In this study, we wanted to investigate the impact of incident venous thromboembolism (VTE) on future risk of atrial fibrillation in a prospective population-based study., Methods and Results: The study included 29 974 subjects recruited from the Tromsø study (1994-1995, 2001-2002, 2007-2008). Incident VTE and atrial fibrillation events were registered from date of enrolment to end of follow-up, December 31, 2010. Cox proportional hazard regression models using age as time-scale and VTE as a time-dependent variable were used to estimate crude and multivariable hazard ratios (HRs) for atrial fibrillation with 95% confidence intervals (CIs). During 16 years of follow up, 540 (1.8%) subjects had an incident VTE event, and 1662 (5.54%) were diagnosed with atrial fibrillation. Among those with VTE, 50 (9.3%) developed subsequent atrial fibrillation. Patients with VTE had 63% higher risk of atrial fibrillation compared to subjects without VTE (multivariable-adjusted HR: 1.63, 95% CI: 1.22 to 2.17). The risk of atrial fibrillation was particularly high during the first 6 months after the VTE event (HR 4.00, 95% CI: 2.21 to 7.25) and among those with PE (HR 1.78, 95% CI: 1.13 to 2.80)., Conclusions: We found that incident VTE was associated with future risk of atrial fibrillation. Our findings support the hypothesis that PE may lead to cardiac dysfunctions that, in turn, could trigger atrial fibrillation.

Background: Atrial fibrillation (AF) is a common cardiac arrhythmia which increases morbidity and mortality. Identification of risk factors is therefore important. We examined the impact of palpitations and cardiovascular risk factors in prediction of AF (all types) and lone AF in a large population-based cohort., Design: We carried out a prospective population-based cohort study., Methods: A total of 22,815 participants from a population survey in 1994-1995 were followed-up for a mean of 11.1 years. Mean age at baseline was 46 years. Measurements of height, weight, blood pressure, heart rate, total cholesterol and high-density lipoprotein (HDL)-cholesterol, and information on palpitations, diabetes, angina, myocardial infarction, and antihypertensive treatment were obtained at baseline. The outcome measure was first-ever AF, documented on an electrocardiogram. Cox proportional hazards regression model was used to estimate hazard ratios (HRs) for AF., Results: Palpitations were associated with increased risk of AF in both women (HR 1.62, 95% confidence interval [CI] 1.29-2.02) and men (HR 1.91, 95% CI 1.54-2.35). For hypertension the HR for AF was 1.98 (1.46-2.69) in women and 1.40 (1.13-1.74) in men. The HR for 1 SD increase in body mass index (BMI) was 1.16 (1.06-1.27) in women and 1.47 (1.32-1.63) in men. Body height and BMI were associated with increased risk for lone AF in men., Conclusion: Palpitations, hypertension and BMI were predictive of future atrial fibrillation in both sexes.

Background: Inflammatory biomarkers are reported as risk factors for atrial fibrillation (AF), but their impact is uncertain., Objective: We investigated the associations between inflammatory biomarkers and future AF in a large general cohort., Methods: Available markers were white blood cells (WBCs) with subgroups, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and osteoprotegerin (OPG). A total of 6315 men and women from a population survey in Tromsø, Norway in 1994 to 1995 were followed for a mean of 10.9 years. Mean age at baseline was 60 years. Measurements of height, weight, blood pressure, heart rate, total cholesterol, high-density lipoprotein (HDL) cholesterol, WBC count, and information on diabetes, angina, myocardial infarction, and antihypertensive treatment, were obtained at baseline. Fibrinogen, hs-CRP, and OPG were obtained at a follow-up visit. The outcome measure was first-ever AF, documented on an electrocardiogram. The Cox proportional hazards regression model was used to estimate hazard ratios of AF., Results: In the multivariable analysis, adjusted for traditional cardiovascular risk factors and other inflammatory biomarkers, hs-CRP was associated with AF in men only (hazard ratio = 1.14 for a 1 SD increase; 95% CI, 1.02-1.28). There was a significant increase in AF across quartiles of WBCs in men (P = 0.007) and in the total study population (P = 0.004). OPG was associated with AF in patients free of coronary heart disease at baseline. Fibrinogen and subgroups of WBCs showed no significant association with AF., Conclusion: This population-based cohort study showed that hs-CRP was independently associated with AF in men, but apparently not in women, and that patients with WBCs in the upper quartile had increased risk of AF., (Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.)

We expanded our genome-wide association study on atrial fibrillation (AF) in Iceland, which previously identified risk variants on 4q25, and tested the most significant associations in samples from Iceland, Norway and the United States. A variant in the ZFHX3 gene on chromosome 16q22, rs7193343-T, associated significantly with AF (odds ratio OR = 1.21, P = 1.4 x 10(-10)). This variant also associated with ischemic stroke (OR = 1.11, P = 0.00054) and cardioembolic stroke (OR = 1.22, P = 0.00021) in a combined analysis of five stroke samples.

Aims To identify robust circulating predictors for incident atrial fibrillation (AF) using classical regressions and machine learning (ML) techniques within a broad spectrum of candidate variables. Methods and results In pooled European community cohorts (n = 42 280 individuals), 14 routinely available biomarkers mirroring distinct pathophysiological pathways including lipids, inflammation, renal, and myocardium-specific markers (N-terminal pro B-type natriuretic peptide [NT-proBNP], high-sensitivity troponin I [hsTnI]) were examined in relation to incident AF using Cox regressions and distinct ML methods. Of 42 280 individuals (21 843 women [51.7%]; median [interquartile range, IQR] age, 52.2 [42.7, 62.0] years), 1496 (3.5%) developed AF during a median follow-up time of 5.7 years. In multivariable-adjusted Cox-regression analysis, NT-proBNP was the strongest circulating predictor of incident AF [hazard ratio (HR) per standard deviation (SD), 1.93 (95% CI, 1.82–2.04); P < 0.001]. Further, hsTnI [HR per SD, 1.18 (95% CI, 1.13–1.22); P < 0.001], cystatin C [HR per SD, 1.16 (95% CI, 1.10–1.23); P < 0.001], and C-reactive protein [HR per SD, 1.08 (95% CI, 1.02–1.14); P = 0.012] correlated positively with incident AF. Applying various ML techniques, a high inter-method consistency of selected candidate variables was observed. NT-proBNP was identified as the blood-based marker with the highest predictive value for incident AF. Relevant clinical predictors were age, the use of antihypertensive medication, and body mass index. Conclusion Using different variable selection procedures including ML methods, NT-proBNP consistently remained the strongest blood-based predictor of incident AF and ranked before classical cardiovascular risk factors. The clinical benefit of these findings for identifying at-risk individuals for targeted AF screening needs to be elucidated and tested prospectively. [ABSTRACT FROM AUTHOR]

Aims: Limited evidence is available on the temporal relationship between atrial fibrillation (AF) and ischaemic stroke and their impact on mortality in the community. We sought to understand the temporal relationship of AF and ischaemic stroke and to determine the sequence of disease onset in relation to mortality.Methods and Results: Across five prospective community cohorts of the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE) project we assessed baseline cardiovascular risk factors in 100 132 individuals, median age 46.1 (25th-75th percentile 35.8-57.5) years, 48.4% men. We followed them for incident ischaemic stroke and AF and determined the relation of subsequent disease diagnosis with overall mortality. Over a median follow-up of 16.1 years, N = 4555 individuals were diagnosed solely with AF, N = 2269 had an ischaemic stroke but no AF diagnosed, and N = 898 developed both, ischaemic stroke and AF. Temporal relationships showed a clustering of diagnosis of both diseases within the years around the diagnosis of the other disease. In multivariable-adjusted Cox regression analyses with time-dependent covariates subsequent diagnosis of AF after ischaemic stroke was associated with increased mortality [hazard ratio (HR) 4.05, 95% confidence interval (CI) 2.17-7.54; P < 0.001] which was also apparent when ischaemic stroke followed after the diagnosis of AF (HR 3.08, 95% CI 1.90-5.00; P < 0.001).Conclusion: The temporal relations of ischaemic stroke and AF appear to be bidirectional. Ischaemic stroke may precede detection of AF by years. The subsequent diagnosis of both diseases significantly increases mortality risk. Future research needs to investigate the common underlying systemic disease processes. [ABSTRACT FROM AUTHOR]

The effects of interventions on multiple lifestyle and metabolic risk factors, initiated in midlife or later in a healthy population, on the long-term risk of first-ever stroke is not known. A particular methodological challenge in observational studies is to estimate the unbiased effect of a time-varying exposure in presence of time-varying confounders, if those confounders are affected by prior exposure. In such cases, the parametric g-formula can be applied to estimate an unbiased effect. We applied the parametric g-formula to estimate the 18-years (1994-2012) cumulative stroke risk under different scenarios of hypothetical interventions on levels of blood pressure, cholesterol, weight, physical activity, smoking and alcohol intake; and compared these to the observed scenario, to calculate the population risk ratios and risk differences. Among 14,796 eligible participants in the prospective, population-based Tromsø study (baseline mean age 46.1 years, 51% women), the observed 18-years stroke risk was 5.9%. A feasible joint hypothetical intervention on six lifestyle and metabolic risk factors would reduce the 18-year stroke risk by 32% (95% confidence interval 16, 44). A combination of more intensive interventions reduced the estimated 18-years stroke risk by 64% (95% confidence interval 40, 80). Blood pressure reduction and quitting smoking significantly reduced the risk when applied separately. [ABSTRACT FROM AUTHOR]

Aims Serum uric acid (SUA) has been associated with cardiovascular disease in population studies, but its relation to atrial fibrillation (AF) is largely unknown. The aim of this study was to investigate the association between baseline SUA and future AF in a large population-based cohort. Methods and results A total of 6308 men and women from a population survey in Tromsø, Norway in 1994–95 were followed-up for 10.8 years. The mean age at baseline was 60 years. Information on angina, myocardial infarction, diabetes, anti-hypertensive and diuretic treatment, physical activity, smoking and alcohol, and measurements of height, weight, blood pressure, SUA, total cholesterol, and high density lipoprotein-cholesterol were obtained at baseline. The outcome measure was first-ever AF, documented on an electrocardiogram. We identified 572 cases of incident AF. In multivariable Cox proportional hazards regression analysis adjusted for cardiovascular risk factors and concomitant diseases, SUA was associated with AF in both sexes. Hazard ratio per 1 SD increase in SUA (91 μmol/L) was 1.40 [95% confidence intervals (CI), 1.14–1.72] in women and 1.17 (95% CI, 1.02–1.36) in men. The upper quartile of SUA conferred a 76% increased risk for AF in women and 49% in men as compared with the lowest quartile. Conclusion This prospective population-based cohort study showed that baseline SUA was associated with an increased risk for future AF in both sexes. [ABSTRACT FROM PUBLISHER]

Electrocardiographic measures are indicative of the function of the cardiac conduction system. To search for sequence variants that modulate heart rate, PR interval and QRS duration in individuals of European descent, we performed a genome-wide association study in ∼10,000 individuals and followed up the top signals in an additional ∼10,000 individuals. We identified several genome-wide significant associations (with P < 1.6 × 10−7). We identified one locus for heart rate (MYH6), four for PR interval (TBX5, SCN10A, CAV1 and ARHGAP24) and four for QRS duration (TBX5, SCN10A, 6p21 and 10q21). We tested for association between these loci and subjects with selected arrhythmias in Icelandic and Norwegian case-control sample sets. We observed correlations between TBX5 and CAV1 and atrial fibrillation (P = 4.0 × 10−5 and P = 0.00032, respectively), between TBX5 and advanced atrioventricular block (P = 0.0067), and between SCN10A and pacemaker implantation (P = 0.0029). We also replicated previously described associations with the QT interval. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore sex-specific associations between systolic blood pressure (SBP), hypertension, and the risk of incident atrial fibrillation (AF) subtypes, including paroxysmal, persistent, and permanent AF, in a general population. A total of 13,137 women and 11,667 men who participated in the fourth survey of the Tromsø Study (1994–1995) were followed up for incident AF until the end of 2016. Cox proportional hazards regression analysis was conducted using fractional polynomials for SBP to provide sex- and AF-subtype-specific hazard ratios (HRs) for SBP. An SBP of 120 mmHg was used as the reference. Models were adjusted for other cardiovascular risk factors. Over a mean follow-up of 17.6 ± 6.6 years, incident AF occurred in 914 (7.0%) women (501 with paroxysmal/persistent AF and 413 with permanent AF) and 1104 (9.5%) men (606 with paroxysmal/persistent AF and 498 with permanent AF). In women, an SBP of 180 mmHg was associated with an HR of 2.10 (95% confidence interval [CI] 1.60–2.76) for paroxysmal/persistent AF and an HR of 1.80 (95% CI 1.33–2.44) for permanent AF. In men, an SBP of 180 mmHg was associated with an HR of 1.90 (95% CI 1.46–2.46) for paroxysmal/persistent AF, while there was no association with the risk of permanent AF. In conclusion, increasing SBP was associated with an increased risk of both paroxysmal/persistent AF and permanent AF in women, but only paroxysmal/persistent AF in men. Our findings highlight the importance of sex-specific risk stratification and optimizing blood pressure management for the prevention of AF subtypes in clinical practice. [ABSTRACT FROM AUTHOR]