Incidence and prognostic significance of newly-diagnosed atrial fibrillation among older U.S. veterans hospitalized with COVID-19

Most prior studies on the prognostic significance of newly-diagnosed atrial fibrillation (AF) in COVID-19 did not differentiate newly-diagnosed AF from pre-existing AF. To determine the association between newly-diagnosed AF and in-hospital and 30-day mortality among regular users of Veterans Health Administration using data linked to Medicare. We identified Veterans aged ≥ 65 years who were hospitalized for ≥ 24 h with COVID-19 from 06/01/2020 to 1/31/2022 and had ≥ 2 primary care visits within 24 months prior to the index hospitalization. We performed multivariable logistic regression analyses to estimate adjusted risks, risk differences (RD), and odds ratios (OR) for the association between newly-diagnosed AF and the mortality outcomes adjusting for patient demographics, baseline comorbidities, and presence of acute organ dysfunction on admission. Of 23,299 patients in the study cohort, 5.3% had newly-diagnosed AF, and 29.2% had pre-existing AF. In newly-diagnosed AF adjusted in-hospital and 30-day mortality were 16.5% and 22.7%, respectively. Newly-diagnosed AF was associated with increased mortality compared to pre-existing AF (in-hospital: OR 2.02, 95% confidence interval [CI] 1.72-2.37; RD 7.58%, 95% CI 5.54-9.62) (30-day: OR 1.86; 95% CI 1.60-2.16; RD 9.04%, 95% CI 6.61-11.5) or no AF (in-hospital: OR 2.24, 95% CI 1.93-2.60; RD 8.40%, 95% CI 6.44-10.4) (30-day: 2.07, 95% CI 1.80-2.37; RD 10.2%, 95% CI 7.89-12.6). There was a smaller association between pre-existing AF and the mortality outcomes. Newly-diagnosed AF is an important prognostic marker for patients hospitalized with COVID-19. Whether prevention or treatment of AF improves clinical outcomes in these patients remains unknown.

The bidirectional association between atrial fibrillation and myocardial infarction

Atrial fibrillation (AF) is associated with an increased risk of myocardial infarction (MI) and vice versa. This bidirectional association relies on shared risk factors as well as on several direct and indirect mechanisms, including inflammation, atrial ischaemia, left ventricular remodelling, myocardial oxygen supply-demand mismatch and coronary artery embolism, through which one condition can predispose to the other. Patients with both AF and MI are at greater risk of stroke, heart failure and death than patients with only one of the conditions. In this Review, we describe the bidirectional association between AF and MI. We discuss the pathogenic basis of this bidirectional relationship, describe the risk of adverse outcomes when the two conditions coexist, and review current data and guidelines on the prevention and management of both conditions. We also identify important gaps in the literature and propose directions for future research on the bidirectional association between AF and MI. The Review also features a summary of methodological approaches for the study of bidirectional associations in population-based studies.

Association Between Electrocardiographic Age and Cardiovascular Events in Community Settings: The Framingham Heart Study

BACKGROUND

Deep neural networks have been used to estimate age from ECGs, the electrocardiographic age (ECG-age), which predicts adverse outcomes. However, this prediction ability has been restricted to clinical settings or relatively short periods. We hypothesized that ECG-age is associated with death and cardiovascular outcomes in the long-standing community-based FHS (Framingham Heart Study).

METHODS

We tested the association of ECG-age with chronological age in the FHS cohorts in ECGs from 1986 to 2021. We calculated the gap between chronological and ECG-age (Δage) and classified individuals as having normal, accelerated, or decelerated aging, if Δage was within, higher, or lower than the mean absolute error of the model, respectively. We assessed the associations of Δage, accelerated and decelerated aging with death or cardiovascular outcomes (atrial fibrillation, myocardial infarction, and heart failure) using Cox proportional hazards models adjusted for age, sex, and clinical factors.

RESULTS

The study population included 9877 FHS participants (mean age, 55±13 years; 54.9% women) with 34 948 ECGs. ECG-age was correlated to chronological age (r=0.81; mean absolute error, 9±7 years). After 17±8 years of follow-up, every 10-year increase of Δage was associated with 18% increase in all-cause mortality (hazard ratio [HR], 1.18 [95% CI, 1.12-1.23]), 23% increase in atrial fibrillation risk (HR, 1.23 [95% CI, 1.17-1.29]), 14% increase in myocardial infarction risk (HR, 1.14 [95% CI, 1.05-1.23]), and 40% increase in heart failure risk (HR, 1.40 [95% CI, 1.30-1.52]), in multivariable models. In addition, accelerated aging was associated with a 28% increase in all-cause mortality (HR, 1.28 [95% CI, 1.14-1.45]), whereas decelerated aging was associated with a 16% decrease (HR, 0.84 [95% CI, 0.74-0.95]).

CONCLUSIONS

ECG-age was highly correlated with chronological age in FHS. The difference between ECG-age and chronological age was associated with death, myocardial infarction, atrial fibrillation, and heart failure. Given the wide availability and low cost of ECG, ECG-age could be a scalable biomarker of cardiovascular risk.

The association between eicosanoids and incident atrial fibrillation in the Framingham Heart Study

Chronic inflammation is a continuous low-grade activation of the systemic immune response. Whereas downstream inflammatory markers are associated with atrial fibrillation (AF), upstream inflammatory effectors including eicosanoids are less studied. To examine the association between eicosanoids and incident AF. We used a liquid chromatography-mass spectrometry for the non-targeted measurement of 161 eicosanoids and eicosanoid-related metabolites in the Framingham Heart Study. The association of each eicosanoid and incident AF was assessed using Cox proportional hazards models and adjusted for AF risk factors, including age, sex, height, weight, systolic/diastolic blood pressure, current smoking, antihypertensive medication, diabetes, history of myocardial infarction and heart failure. False discovery rate (FDR) was used to adjust for multiple testing. Eicosanoids with FDR < 0.05 were considered significant. In total, 2676 AF-free individuals (mean age 66 ± 9 years, 56% females) were followed for mean 10.8 ± 3.4 years; 351 participants developed incident AF. Six eicosanoids were associated with incident AF after adjusting for multiple testing (FDR < 0.05). A joint score was built from the top eicosanoids weighted by their effect sizes, which was associated with incident AF (HR = 2.72, CI = 1.71-4.31, P = 2.1 × 10^-5). In conclusion, six eicosanoids were associated with incident AF after adjusting for clinical risk factors for AF.

The association between social network index, atrial fibrillation, and mortality in the Framingham Heart Study

Social isolation might be considered as a marker of poor health and higher mortality. The aim of our analysis was to assess the association of social network index (SNI) with incident AF and death. We selected participants aged ≥ 55 years without prevalent AF from the Framingham Heart Study. We evaluated the association between social isolation measured by the Berkman-Syme Social Network Index (SNI), incident AF, and mortality without diagnosed AF. We assessed the risk factor-adjusted associations between SNI (the sum of 4 components: marriage status, close friends/relatives, religious service attendance, social group participation), incident AF, and mortality without AF by using Fine-Gray competing risk regression models. We secondarily examined the outcome of all-cause mortality. We included 3454 participants (mean age 67 ± 10 years, 58% female). During 11.8 ± 5.2 mean years of follow-up, there were 686 incident AF cases and 965 mortality without AF events. Individuals with fewer connections had lower rates of incident AF (P = 0.04) but higher rates of mortality without AF (P = 0.03). Among SNI components, only social group participation was associated with higher incident AF (subdistribution hazards ratio [sHR] 1.35, 95% CI 1.16-1.57, P = 0.0001). For mortality without AF, social group participation (sHR = 0.81, 95% CI 0.71-0.93, P = 0.002) and regular religious service attendance sHR = 0.76, 95% CI 0.67-0.87, P < 0.0001) were associated with lower risk of death. Social isolation was associated with a higher rate of mortality without diagnosed AF. In contrast to our hypothesis, we observed that poor social connectedness was associated with a lower rate of incident AF. This finding should be interpreted cautiously since there were very few participants in the lowest social connectedness group. Additionally, the seemingly protective effect of social isolation on AF incidence may be simply an artifact of the strong association between social isolation and increased mortality rate in combination with the large number of deaths as compared to AF events in our study. Further study is warranted.

Neck Circumference and Risk of Incident Atrial Fibrillation in the Framingham Heart Study

Background

Increased neck circumference, a proxy for upper‐body subcutaneous fat, is associated with cardiovascular risk and metabolic risk factors, accounting for body mass index (BMI) and waist circumference. The association between neck circumference and incident atrial fibrillation (AF) is unclear. The aim of current study was to evaluate the association between neck circumference and incident AF.

Methods and Results

We selected participants from the Framingham Heart Study aged ≥55 years without diagnosed AF and with available neck circumference, BMI, and waist circumference measurements. We defined high neck circumference as ≥14 inches in women and ≥17 inches in men on the basis of the Contal and O’Quigley changepoint method. We used Fine‐Gray models to estimate subdistribution hazards ratios (sHRs) for the association between neck circumference and incident AF accounting for the competing risk of death. We adjusted models for clinical risk factors. We then additionally adjusted separately for BMI, waist circumference, and height/weight. The study sample included 4093 participants (mean age 64±7 years, 55% female). During 11.2±5.7 mean years of follow‐up, incident AF occurred in 571 participants. High neck circumference was associated with incident AF (sHR for high versus low: 1.58; 95% CI, 1.32–1.90, P<0.0001). The association remained significant after adjustment for BMI (sHR, 1.51; 95% CI, 1.21–1.89; P=0.0003), waist circumference (sHR, 1.47; 95% CI, 1.18–1.83; P<0.0001), and height/weight (sHR, 1.37; 95% CI, 1.09–1.72; P=0.007).

Conclusions

High neck circumference was associated with incident AF adjusting for traditional adiposity measures such as BMI and waist circumference.

Evaluation of a Multi-Session Group Designed to Prevent Commercial Sexual Exploitation of Minors: The "My Life My Choice" Curriculum

The commercial sexual exploitation (CSE) of children is a consequential public health and criminal justice problem, but no CSE prevention programs have been evaluated. The Boston-based My Life My Choice (MLMC) program offers a multisession psychoeducation group to girls who are identified as "at-disproportionate-risk" for CSE victimization and trains other agencies throughout the U.S. to offer this curriculum. The curriculum was designed to improve knowledge about the commercial sex industry and shift-related attitudes and behaviors. The current project was a multi-year, multi-site evaluation to assess the effectiveness of the MLMC prevention group. Using a one-group longitudinal design, changes in participant behavior and CSE knowledge were measured at baseline (n = 354), upon group completion (n = 296), and 3 months after group completion (n = 241). The sample was 95% female-identified, 28% Black/African American, 26% White/non-Hispanic, 25% Hispanic/Latina, and 22% other race. The mean age of participants was 15.6 years old. Approximately 28% identified as bisexual, and 10% identified as lesbian, asexual, pansexual, or other. In multivariable-adjusted models, participants reported fewer episodes of sexually explicit behavior at follow up as compared to baseline (relative risk [RR]: 0.52, 95% confidence interval [CI]: 0.37-0.72 at Follow-up 1, and 0.53, 95% CI: 0.35-0.82 at Follow-up 2). Participants were 24% less likely to report dating abuse at Follow-up 2 as compared to baseline (p = .06). In addition, as compared to baseline, participants were 40% more likely to have given help or information about CSE to a friend at Follow-up 2, and participants demonstrated increased knowledge and awareness about CSE and its harms over the follow-up period. Although additional evaluation using a comparison group and long-term follow up would increase confidence that observed changes are attributable to the group instead of other factors, results suggest that the MLMC curriculum may be effective in reducing the risk of CSE and improving other conditions for youth who are at-disproportionate-risk of CSE.

Association Between Leptin, Cognition, and Structural Brain Measures Among "Early" Middle-Aged Adults: Results from the Framingham Heart Study Third Generation Cohort

BACKGROUND

There is growing interest in the pathophysiological processes of preclinical Alzheimer's disease (AD), including the potential role of leptin. Human studies have shown that both low and high levels of leptin can be associated with worse neurocognitive outcomes, suggesting this relationship may be moderated by another risk factor.

OBJECTIVE

We examined the association between plasma leptin levels and both neuropsychological test performance and structural neuroimaging and assessed whether body mass index (BMI) is an effect modifier of these associations.

METHODS

Our study sample consisted of 2,223 adults from the Framingham Heart Study Third Generation Cohort (average age = 40 years, 53% women).

RESULTS

Among the entire sample, there was no association between leptin and any of the neuropsychological domain measures or any of the MRI brain volume measures, after adjustment for BMI, APOE4, and other clinical factors. However, we did observe that BMI category was an effect modifier for the association between leptin and verbal memory (p for interaction = 0.03), where higher levels of leptin were associated with better performance among normal weight participants (BMI 18.5-24.9) kg/m2 (beta = 0.12, p = 0.02). No association was observed between leptin level and verbal memory test performance among participants who were overweight or obese.

CONCLUSION

These findings suggest that the association between leptin and cognitive function is moderated by BMI category. Prospective examination of individuals transitioning from middle age to older adulthood will help to clarify the contribution of leptin to AD and other neurodegenerative conditions.

Temporal trends in cause-specific mortality among individuals with newly diagnosed atrial fibrillation in the Framingham Heart Study

BACKGROUND

All-cause mortality following atrial fibrillation (AF) has decreased over time. Data regarding temporal trends in causes of death among individuals with AF are scarce. The aim of our study was to analyze temporal trends in cause-specific mortality and predictors for cardiovascular (CVD) and non-CVD deaths among participants with incident AF in the Framingham Heart Study.

METHODS

We categorized all newly diagnosed AF cases according to age at AF diagnosis (< 70, 70 to < 80, and ≥ 80 years) and epoch of AF diagnosis (< 1990, 1990-2002, and ≥ 2003). We followed participants until death or the last follow-up. We categorized death causes into CVD, non-CVD, and unknown causes. For each age group, we tested for trends in the cumulative incidence of cause-specific death across epochs. We fit multivariable Fine-Gray models to assess subdistribution hazard ratios (HR) between clinical risk factors at AF diagnosis and cause-specific mortality.

RESULTS

We included 2125 newly diagnosed AF cases (mean age 75.5 years, 47.8% women). During a median follow-up of 4.8 years, 1657 individuals with AF died. There was evidence of decreasing CVD mortality among AF cases diagnosed < 70 years and 70 to < 80 years (p_trend < 0.001) but not ≥ 80 years (p = 0.76). Among the cases diagnosed < 70 years, the cumulative incidence of CVD death at 75 years was 67.7% in epoch 1 and 13.9% in epoch 3; among those 70 to < 80 years, the incidence at 85 years was 58.9% in epoch 1 and 18.9% in epoch 3. Advancing age (HR per 1 SD increase 6.33, 95% CI 5.44 to 7.37), prior heart failure (HR 1.49, 95% CI 1.14-1.94), and prior myocardial infarction (HR 1.44, 95% CI 1.15-1.80) were associated with increased rate of CVD death.

CONCLUSIONS

In this community-based cohort, CVD mortality among AF cases decreased over time. Most deaths in individuals with AF are no longer CVD-related, regardless of age at AF diagnosis.

Relations of arterial stiffness and endothelial dysfunction with incident venous thromboembolism

INTRODUCTION

Association between arterial vascular dysfunction and risk of venous thromboembolism (VTE) is uncertain. We determined the associations between comprehensive measures of arterial vascular function and risk of incident VTE in a community-based cohort study with robust longitudinal follow-up.

MATERIALS AND METHODS

In the Framingham Heart Study Original, Offspring, Third Generation, and Omni cohorts, we measured carotid-femoral pulse wave velocity and central pulse pressure (n = 8261, age 51.5 ± 15.5 years, 54% women), flow-mediated dilation and hyperemic velocity (n = 6540, age 47.9 ± 14.1 years, 54% women), and peripheral arterial tonometry ratio (n = 4998, age 54.3 ± 16.0 years, 52% women). Deep venous thrombosis and pulmonary embolism were diagnosed with imaging studies and adjudicated by three Framingham Heart Study physicians.

RESULTS AND CONCLUSIONS

The rate of incident VTE was 1.6-2.1 per 1000 person-years during mean follow-up of 8.5-11.2 years. In age- and sex-adjusted Cox proportional hazards regression models, carotid-femoral pulse wave velocity was associated with increased risk of VTE (HR 1.32, 95% CI 1.05-1.66, p = 0.02), however the association was no longer statistically significant after multivariable adjustment (HR 1.24, 95% CI 0.96-1.61, p = 0.10). None of the other vascular variables were associated with the risk of VTE in any of the models. In our comprehensive examination of arterial vascular function and risk of VTE, we did not observe any association between select arterial function measures and risk of VTE after multivariable adjustment.

New biomarkers from multiomics approaches: improving risk prediction of atrial fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia leading to many adverse outcomes and increased mortality. Yet the molecular mechanisms underlying AF remain largely unknown. Recent advances in high-throughput technologies make large-scale molecular profiling possible. In the past decade, multiomics studies of AF have identified a number of potential biomarkers of AF. In this review, we focus on the studies of multiomics profiles with AF risk. We summarize recent advances in the discovery of novel biomarkers for AF through multiomics studies. We also discuss limitations and future directions in risk assessment and discovery of therapeutic targets for AF.

P-wave signal-averaged electrocardiography: Reference values, clinical correlates, and heritability in the Framingham Heart Study

BACKGROUND

P-wave signal-averaged electrocardiography (P-SAECG) quantifies atrial electrical activity. P-SAECG measures and their clinical correlates and heritability have had limited characterization in community-based cohorts.

OBJECTIVE

The purpose of this study was to (1) establish reference values; (2) identify clinical risk factors associated with P-SAECG; and (3) estimate genetic heritability for P-SAECG traits.

METHODS

We performed P-SAECG in 2 generations of Framingham Heart Study participants. We performed backward elimination regression models to assess associations of clinical factors with each SAECG trait (P-wave [PW] duration, root mean square voltage in terminal 40 ms [RMS40], terminal 30 ms RMS30, terminal 20 ms RMS20, RMS PW, and PW integral). We estimated the adjusted genetic heritability of P-SAECG measures using the Sequential Oligogenic Linkage Analysis Routines (SOLAR) program.

RESULTS

We included 4307 participants (age 55 ± 14 years; 56% female). The reference values were derived from 1752 participants without cardiovascular risk factors. Median (2.5th percentile; 97.5th percentile) total PW duration was 118 ms (93; 146) in women and 128 ms (104; 158) in men in the reference sample, and 121 ms (94; 151) in women and 129 ms (103; 159) in the entire study cohort (broad sample). In the broad sample, after adjusting for age and sex, total PW duration was positively associated with height, weight, prevalent heart failure, history of atrial fibrillation (AF), and atrioventricular node blockers, and negatively associated with smoking, waist circumference, heart rate, and diabetes. The estimated heritability of P-SAECG traits was moderate, ranging from 11.9% for RMS30 to 24.9% for PW integral.

CONCLUSION

P-SAECG traits are associated with multiple AF-related risk factors and are moderately heritable.

Association Between Frailty and Atrial Fibrillation in Older Adults: The Framingham Heart Study Offspring Cohort

Background Frailty is associated bidirectionally with cardiovascular disease. However, the relations between frailty and atrial fibrillation (AF) have not been fully elucidated. Methods and Results Using the FHS (Framingham Heart Study) Offspring cohort, we sought to examine both the association between frailty (2005-2008) and incident AF through 2016 and the association between prevalent AF and frailty status (2011-2014). Frailty was defined using the Fried phenotype. Models adjusted for age, sex, and smoking. Cox proportional hazards models, adjusted for competing risk of death, assessed the association between prevalent frailty and incident AF. Logistic regression models assessed the association between prevalent AF and new-onset frailty. For the incident AF analysis, we included 2053 participants (56% women; mean age, 69.7±6.9 years). By Fried criteria, 1018 (50%) were robust, 903 (44%) were prefrail, and 132 (6%) were frail. In total, 306 incident cases of AF occurred during an average 9.2 (SD, 3.1) follow-up years. After adjustment, there was no statistically significant association between prevalent frailty status and incident AF (prefrail versus robust: hazard ratio [HR], 1.22 [95% CI, 0.95-1.55]; frail versus robust: HR, 0.92 [95% CI, 0.57-1.47]). At follow-up, there were 111 new cases of frailty. After adjustment, there was no statistically significant association between prevalent AF and new-onset frailty (odds ratio, 0.48 [95% CI, 0.17-1.36]). Conclusions Although a bidirectional association between frailty and cardiovascular disease has been suggested, we did not find evidence of an association between frailty and AF. Our findings may be limited by sample size and should be further explored in other populations.

Novel Risk Modeling Approach of Atrial Fibrillation With Restricted Mean Survival Times: Application in the Framingham Heart Study Community-Based Cohort

BACKGROUND

Risk prediction models for atrial fibrillation (AF) do not give information about when AF might develop. Restricted mean survival time (RMST) quantifies risk into the time domain. Our objective was to use RMST to re-express individualized AF risk predictions.

METHODS AND RESULTS

We included AF-free participants from the Framingham Heart Study community-based cohorts. We predicted new-onset AF over 10-year follow-up according to baseline covariates: age, height, weight, systolic blood pressure, diastolic blood pressure, current smoking, antihypertensive treatment, diabetes mellitus, prevalent heart failure, and prevalent myocardial infarction. First, we fitted a Cox regression model and estimated the 10-year predicted risk of AF. Second, we fitted an RMST model and estimated the predicted mean time free of AF and alive over a time horizon of 10 years. We included 7586 AF-free participants contributing to 11 088 examinations (mean age 61±11 years, 44% were men). During 10-year follow-up, 822 participants developed AF. The Cox and RMST models were in agreement regarding the direction, strength, and statistical significance of associations for all covariates. Low (<5%), intermediate (5%-15%), and high (>15%) 10-year predicted risk of AF corresponded to predicted mean time alive and free of AF of 9.9, 9.6, and 8.8 years, respectively. A 60-year-old woman with a body mass index of 25 kg/m2, no use of hypertension treatment and no history of heart failure had a predicted mean time alive and free of AF of 9.9 years, whereas a 70-year-old man with a body mass index of 30 kg/m2, use of hypertension treatment, and with prevalent heart failure had a predicted mean time alive and free of AF of 7.9 years.

CONCLUSIONS

The RMST can be used to develop risk prediction models to express results in a time scale. RMST may offer a complementary risk communication tool for AF in clinical practice.

A longitudinal evaluation of a survivor-mentor program for child survivors of sex trafficking in the United States

BACKGROUND

Commercial sexual exploitation (CSE) of children is a significant public health and criminal justice problem, but there are few evaluated models of CSE mentorship service.

OBJECTIVES

To assess whether youth who participated in a CSE survivor-mentor program evidenced changes in CSE victimization, dating abuse victimization, health, delinquency, social support, and coping during the year following their enrollment in the program.

PARTICIPANTS

41 youth who were CSE-experienced at baseline (72%) or determined very high risk, 11-18 years old, 95% female, 58% heterosexual, 29% White, 29% Hispanic, and 42% other races/ethnicities.

SETTING

An urban city in the Northeast United States.

METHODS

We used a one-group repeated measures design and a GEE analysis. Data were collected at baseline, six months after baseline (71% follow-up) and 12 months after baseline (68% follow-up).

RESULTS

At baseline 72% could be characterized as CSE-experienced, while at 6 months the percentage decreased to 24% (p < 0.001) and at 12 months to 14% (p < 0.001). After 6 months of receiving survivor-mentor services, youth were less likely to have experienced CSE, engaged in sexually explicit behavior (SEB), used illicit drugs, engaged in delinquent behavior, been arrested or detained by police, and they had better social support and coping skills. After 12 months, youth were less likely to have experienced CSE, to have engaged in delinquent behavior, be arrested or detained by police, and had improved coping skills.

CONCLUSION

Findings demonstrate that youth who received survivor-mentor services from MLMC experienced improved well-being and less drug use, delinquent behavior, and exploitation.

Protein Biomarkers and Risk of Atrial Fibrillation: The FHS

BACKGROUND

Identification of protein biomarkers associated with incident atrial fibrillation (AF) may improve the understanding of the pathophysiology, risk prediction, and development of new therapeutics for AF. We examined the associations between 85 protein biomarkers and incident AF.

METHODS

We included participants ≥50 years of age from the FHS (Framingham Heart Study) Offspring and Third Generation cohorts, who had 85 fasting plasma proteins measured using Luminex xMAP platform. Hazard ratios (per 1 SD increment of rank-normalized biomarker [hazard ratio]) and 95% CIs for incident AF were calculated using Cox regression models adjusted for age, sex, height, weight, current smoking, systolic blood pressure, diastolic blood pressure, hypertension treatment, diabetes mellitus, valvular heart disease, prevalent myocardial infarction, and prevalent heart failure. We used the false discovery rate to account for multiple testing.

RESULTS

The study sample comprised 3378 participants (54% women) with mean (SD) age of 61.5 (8.4) years. In total, 401 developed AF over a mean follow-up of 12.3±3.8 years. We observed lower hazard of incident AF associated with higher mean levels of IGF1 (insulin-like growth factor 1; hazard ratio per 1 SD increment in protein level, 0.84 [95% CI, 0.76-0.93]), and higher hazard of incident AF associated with higher mean levels of both IGFBP1 (insulin-like growth factor-binding protein 1; hazard ratio, 1.24 [95% CI, 1.1-1.39]) and NT-proBNP (N-terminal pro-B-type natriuretic peptide; hazard ratio, 1.73 [95% CI, 1.52-1.96]).

CONCLUSIONS

Decreased levels of IGF1 and increased levels of IGFBP1 and NT-proBNP were associated with higher risk of incident AF.

Association of Nonalcoholic Fatty Liver Disease With Lower Brain Volume in Healthy Middle-aged Adults in the Framingham Study

Importance

Nonalcoholic fatty liver disease (NAFLD) is a common condition that is most often asymptomatic. It is associated with metabolic syndrome, incident diabetes, carotid atherosclerosis, and endothelial dysfunction, conditions that in turn are strongly linked with brain damage and cognitive impairment. However, it is not known whether NAFLD is associated with structural brain measures in humans.

Objective

To assess the association between prevalent NAFLD and brain magnetic resonance imaging (MRI) measures.

Design, Setting, and Participants

The cross-sectional association between NAFLD and brain MRI measures was assessed from November 6, 2002, to March 16, 2011, in 766 individuals from the Offspring cohort of the Framingham Study. Participants were included if they did not have excessive alcohol intake and were free of stroke and dementia. Data analysis was conducted from December 30, 2015, to June 15, 2016.

Exposures

Nonalcoholic fatty liver disease was assessed by multidetector computed tomographic scans of the abdomen.

Main Outcomes and Measures

Linear or logistic regression models were used to evaluate the cross-sectional association between NAFLD and brain MRI measures, adjusting for age, sex, alcohol consumption, visceral adipose tissue, body mass index, menopausal status, systolic blood pressure, hypertension, current smoking, high-density lipoprotein and low-density lipoprotein cholesterol levels, lipid treatment, type 2 diabetes, cardiovascular disease, physical activity, insulin resistance, C-reactive protein levels, and plasma homocysteine values. Brain MRI measures included total cerebral brain volume, hippocampal and white matter hyperintensity volumes, and presence or absence of covert brain infarcts.

Results

Of the 766 individuals in the study sample (410 women and 356 men; mean [SD] age at the time of brain MRI, 67 [9] years), 137 (17.9%) had NAFLD. Nonalcoholic fatty liver disease was significantly associated with smaller total cerebral brain volume even after adjustment for all the covariates included in the study (β [SE], -0.26 [0.11]; P = .02). Differences in total cerebral brain volume between those with and without NAFLD corresponded to 4.2 years of brain aging in the general sample and to 7.3 years in individuals younger than 60 years of age. No statistically significant associations were observed between NAFLD and hippocampal or white matter hyperintensity volumes or covert brain infarcts.

Conclusions and Relevance

Nonalcoholic fatty liver disease is associated with a smaller total cerebral brain volume, independent of visceral adipose tissue and cardiometabolic risk factors, pointing to a possible link between hepatic steatosis and brain aging.

Distribution of cerebral microbleeds in the East and West: Individual participant meta-analysis

OBJECTIVE

We investigated differences in the anatomical distribution of cerebral microbleeds (CMBs) on MRI, hypothesized to indicate the type of underlying cerebral small vessel disease (SVD), between Eastern and Western general populations.

METHODS

We analyzed data from 11 studies identified by a PubMed search between 1996 and April 2014 according to the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data. Study quality measures indicated low or medium risk of bias. We included stroke-free participants from populations aged between 55 and 75 years, categorized by geographic location (Eastern or Western). We categorized CMB distribution (strictly lobar, deep and/or infratentorial [D/I], or mixed [i.e., CMBs located in both lobar and D/I regions]). We tested the hypothesis that Eastern and Western populations have different anatomical distributions of CMBs using multivariable mixed effects logistic regression analyses adjusted for age, sex, and hypertension and clustering by institution.

RESULTS

Among 8,595 stroke-free individuals (mean age [SD] 66.7 [5.6] years; 48% male; 42% from a Western population), 624 (7.3%) had CMBs (strictly lobar in 3.1%; D/I or mixed in 4.2%). In multivariable mixed effects models, Eastern populations had higher odds of D/I or mixed CMBs (adjusted odds ratio 2.78, 95% confidence interval [CI] 1.77-4.35) compared to Western populations. Eastern populations had a higher number of D/I or mixed CMBs (adjusted prevalence ratio 2.83, 95% CI 1.27-6.31).

CONCLUSIONS

Eastern and Western general populations have different anatomical distributions of CMBs, suggesting differences in the spectrum of predominant underlying SVDs, with potential implications for SVD diagnosis and treatment.

Lifetime risk of atrial fibrillation according to optimal, borderline, or elevated levels of risk factors: cohort study based on longitudinal data from the Framingham Heart Study

OBJECTIVE

To examine the association between risk factor burdens-categorized as optimal, borderline, or elevated-and the lifetime risk of atrial fibrillation.

DESIGN

Community based cohort study.

SETTING

Longitudinal data from the Framingham Heart Study.

PARTICIPANTS

Individuals free of atrial fibrillation at index ages 55, 65, and 75 years were assessed. Smoking, alcohol consumption, body mass index, blood pressure, diabetes, and history of heart failure or myocardial infarction were assessed as being optimal (that is, all risk factors were optimal), borderline (presence of borderline risk factors and absence of any elevated risk factor), or elevated (presence of at least one elevated risk factor) at index age.

MAIN OUTCOME MEASURE

Lifetime risk of atrial fibrillation at index age up to 95 years, accounting for the competing risk of death.

RESULTS

At index age 55 years, the study sample comprised 5338 participants (2531 (47.4%) men). In this group, 247 (4.6%) had an optimal risk profile, 1415 (26.5%) had a borderline risk profile, and 3676 (68.9%) an elevated risk profile. The prevalence of elevated risk factors increased gradually when the index ages rose. For index age of 55 years, the lifetime risk of atrial fibrillation was 37.0% (95% confidence interval 34.3% to 39.6%). The lifetime risk of atrial fibrillation was 23.4% (12.8% to 34.5%) with an optimal risk profile, 33.4% (27.9% to 38.9%) with a borderline risk profile, and 38.4% (35.5% to 41.4%) with an elevated risk profile. Overall, participants with at least one elevated risk factor were associated with at least 37.8% lifetime risk of atrial fibrillation. The gradient in lifetime risk across risk factor burden was similar at index ages 65 and 75 years.

CONCLUSIONS

Regardless of index ages at 55, 65, or 75 years, an optimal risk factor profile was associated with a lifetime risk of atrial fibrillation of about one in five; this risk rose to more than one in three a third in individuals with at least one elevated risk factor.

Clinical and Environmental Correlates of Serum BDNF: A Descriptive Study with Plausible Implications for AD Research

BACKGROUND

Brain derived neurotrophic factor (BDNF) may play a central role in the pathogenesis of Alzheimer's disease (AD) through neurotrophic effects on basal cholinergic neurons. Reduced serum levels of BDND are observed among AD patients and may predict AD risk. Nevertheless, knowledge about factors associated with its levels in blood is lacking.

OBJECTIVE

To identify clinical and demographic correlates of serum BDNF levels.

METHODS

BDNF was measured from serum collected between 1992-1996 and 1998-2001 in participants from the Original and Offspring cohorts of the Framingham Study, respectively. A cross-sectional analysis was done to evaluate the relationship between clinical measures and BDNF levels using standard linear regression and stepwise models. Analyses were conducted in the total sample and separately in each cohort, and were adjusted for age and sex.

RESULTS

BDNF was measured in 3,689 participants (mean age 65 years, 56% women; 82% Offspring). Cigarette smoking and high total cholesterol were associated with elevated BDNF levels, and history of atrial fibrillation was associated with decreased levels. Elevated BDNF levels were related to greater physical activity and lower Tumor Necrosis Factor-α levels in Offspring. Stepwise models also revealed associations with statin use, alcohol consumption and Apolipoprotein Eε4 genotype.

CONCLUSION

Serum BDNF correlates with various metabolic, inflammatory and life-style measures which in turn have been linked with risk of AD. Future studies of serum BDNF should adjust for these correlates and are needed to further explore the underlying interplay between BDNF and other factors in the pathophysiology of cognitive impairment and AD.

Relation of Orthostatic Hypotension With New-Onset Atrial Fibrillation (From the Framingham Heart Study)

Previous studies have reported that orthostatic hypotension (OH) is associated with increased risk of atrial fibrillation (AF). We sought to determine whether the association persists after adjusting for hypertension and other cardiovascular risk factors. We studied the Framingham Heart Study Original cohort participants evaluated between 1981 and 1984 without baseline AF. OH was defined as drop in standing systolic blood pressure (BP) of at least 20 mm Hg or standing diastolic BP of at least 10 mm Hg from their supine values after standing for 2 minutes. We estimated Cox proportional hazards regression models to calculate multivariable-adjusted hazard ratios (HR) for association between OH and risk of incident AF, adjusting for age, sex, seated systolic BP and diastolic BP, resting heart rate, height, weight, current tobacco use, hypertension treatment, diabetes, and history of myocardial infarction and heart failure. Of 1,736 participants (mean age, 71.7 ± 6.5 years, 60% women), 256 (14.8%) had OH at baseline. During 10 years of follow-up, 224 participants developed new AF. In our multivariable-adjusted model, OH (HR 1.61, 95% confidence interval 1.17 to 2.20) and greater orthostatic decrease in mean arterial pressure (MAP) (HR 1.11, 95% confidence interval 1.02 to 1.22 per 8.6 mm Hg change in MAP) were both associated with higher risk of new AF. In conclusion, in our longitudinal community-based sample, OH and orthostatic decline in MAP were significantly associated with increased risk of incident AF after adjustment for systolic BP, diastolic BP, and hypertension treatment.

Genetic Predisposition, Clinical Risk Factor Burden, and Lifetime Risk of Atrial Fibrillation

BACKGROUND

The long-term probability of developing atrial fibrillation (AF) considering genetic predisposition and clinical risk factor burden is unknown.

METHODS

We estimated the lifetime risk of AF in individuals from the community-based Framingham Heart Study. Polygenic risk for AF was derived using a score of ≈1000 AF-associated single-nucleotide polymorphisms. Clinical risk factor burden was calculated for each individual using a validated risk score for incident AF comprised of height, weight, systolic and diastolic blood pressure, current smoking status, antihypertensive medication use, diabetes mellitus, history of myocardial infarction, and history of heart failure. We estimated the lifetime risk of AF within tertiles of polygenic and clinical risk.

RESULTS

Among 4606 participants without AF at 55 years of age, 580 developed incident AF (median follow-up, 9.4 years; 25th-75th percentile, 4.4-14.3 years). The lifetime risk of AF >55 years of age was 37.1% and was substantially influenced by both polygenic and clinical risk factor burden. Among individuals free of AF at 55 years of age, those in low-polygenic and clinical risk tertiles had a lifetime risk of AF of 22.3% (95% confidence interval, 15.4-9.1), whereas those in high-risk tertiles had a risk of 48.2% (95% confidence interval, 41.3-55.1). A lower clinical risk factor burden was associated with later AF onset after adjusting for genetic predisposition (P<0.001).

CONCLUSIONS

In our community-based cohort, the lifetime risk of AF was 37%. Estimation of polygenic AF risk is feasible and together with clinical risk factor burden explains a substantial gradient in long-term AF risk.

Association of amine biomarkers with incident dementia and Alzheimer's disease in the Framingham Study

INTRODUCTION

The identification of novel biomarkers associated with Alzheimer's disease (AD) could provide key biological insights and permit targeted preclinical prevention. We investigated circulating metabolites associated with incident dementia and AD using metabolomics.

METHODS

Plasma levels of 217 metabolites were assessed in 2067 dementia-free Framingham Offspring Cohort participants (mean age = 55.9 ± 9.7 years; 52.4% women). We studied their associations with future dementia and AD risk in multivariate Cox models.

RESULTS

Ninety-three participants developed incident dementia (mean follow-up = 15.6 ± 5.2 years). Higher plasma anthranilic acid levels were associated with greater risk of dementia (hazard ratio [HR] = 1.40; 95% confidence interval [CI] = [1.15-1.70]; P = 8.08 × 10^-4). Glutamic acid (HR = 1.38; 95% CI = [1.11-1.72]), taurine (HR = 0.74; 95% CI = [0.60-0.92]), and hypoxanthine (HR = 0.74; 95% CI = [0.60-0.92]) levels also showed suggestive associations with dementia risk.

DISCUSSION

We identified four biologically plausible, candidate plasma biomarkers for dementia. Association of anthranilic acid implicates the kynurenine pathway, which modulates glutamate excitotoxicity. The associations with hypoxanthine and taurine strengthen evidence that uric acid and taurine may be neuroprotective.

Population Normative Data for the CERAD Word List and Victoria Stroop Test in Younger- and Middle-Aged Adults: Cross-Sectional Analyses from the Framingham Heart Study

BACKGROUND/STUDY CONTEXT

To provide baseline normative data on tests of verbal memory and executive function for nondemented younger- and middle-aged adults.

METHODS

The Consortium to Establish a Registry for Alzheimer's Disease word list memory task (CERAD-WL) and Victoria Stroop Test (VST) were administered to 3362 Framingham Heart Study (FHS) volunteer participants aged 24-78 years. Analyses of the effects of age, gender, and education were conducted. Normative data on traditional measures and error responses are reported for each test.

RESULTS

Traditional measures were significantly associated with both age and education in this cohort. Error responses also evidenced significant age and education effects.

CONCLUSION

These data provide a normative comparison for assessment of verbal memory and executive functioning capabilities in younger- and middle-aged adults and may be utilized as a tool for preclinical studies of disease in this population.

Cerebral Microbleeds as Predictors of Mortality: The Framingham Heart Study

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMB) represent a common magnetic resonance imaging marker of cerebral small vessel disease, increasingly recognized as a subclinical marker of stroke and dementia risk. CMB detection may reflect the cumulative effect of vascular risk burden and be a marker of higher mortality. We investigated the relation of CMB to risk of death in community dwelling participants free of stroke and dementia.

METHODS

We evaluated 1963 Framingham Original and Offspring Cohort participants (mean age 67 years; 54% women) with available brain magnetic resonance imaging and mortality data. Using Cox proportional hazards models, we related CMB to all-cause, cardiovascular, and stroke-related mortality.

RESULTS

Participants with CMB (8.9%) had higher prevalence of cardiovascular risk factors and use of preventive medications. During a mean follow-up of 7.2±2.6 years, we observed 296 deaths. In age- and sex-adjusted analysis, CMB were associated with increased all-cause mortality (hazards ratio, 1.39; 95% confidence interval 1.03-1.88), a relation that was no longer significant after adjustment for cardiovascular risk and preventive medication use (hazards ratio, 1.15; 95% confidence interval, 0.82-1.63).

CONCLUSIONS

CMBs may represent the deleterious effect of cardiovascular risk factors in the cerebral vasculature. Although their presence was associated with increased all-cause mortality, the effect was no longer present after accounting for vascular risk factors and preventive treatment use. Further studies are required to clarify the role of cardiovascular preventive therapies for prevention of mortality in persons with incidental detection of CMB.

Circulating biomarkers and incident ischemic stroke in the Framingham Offspring Study

OBJECTIVE

We related a panel of inflammatory biomarkers to risk of incident ischemic stroke (IIS) in a community-dwelling sample.

METHODS

Stroke-free Framingham offspring attending examination cycle 7 (1998-2001) had 15 circulating inflammatory biomarkers measured. Cox proportional hazard models were used to calculate the hazard ratios (HRs) of IIS per SD increment of each biomarker. Model 1 included age and sex. Model 2 additionally adjusted for systolic blood pressure, hypertension treatment, current smoking, diabetes, cardiovascular disease, and atrial fibrillation. The continuous net reclassification improvement was used to assess the improvement in IIS risk prediction of statistically significant biomarkers from our main analysis over traditional stroke risk factors.

RESULTS

In 3,224 participants (mean age 61 ± 9 years, 54% women), 98 experienced IIS (mean follow-up of 9.8 [±2.2] years). In model 1, ln-C-reactive protein (ln-CRP) (HR 1.28, 95% confidence interval [CI] 1.04-1.56), ln-tumor necrosis factor receptor 2 (ln-TNFR2) (HR 1.33, 95% CI 1.09-1.63), ln-total homocysteine (ln-tHcy) (HR 1.32, 95% CI 1.11-1.58), and vascular endothelial growth factor (VEGF) (HR 1.25, 95% CI 1.07-1.46) were associated with risk of IIS. All associations, except for ln-CRP, remained significant in model 2 (ln-TNFR2: HR 1.24, 95% CI 1.02-1.51; ln-tHcy: HR 1.20, 95% CI 1.01-1.43; and VEGF: HR 1.21, 95% CI 1.04-1.42). The addition of these 4 biomarkers to the clinical Framingham Stroke Risk Profile score improved stroke risk prediction (net reclassification improvement: 0.34, 0.12-0.57; p < 0.05).

CONCLUSIONS

Higher levels of 4 biomarkers-CRP, tHcy, TNFR2, and VEGF-increased risk of IIS and improved the predictive ability of the Framingham Stroke Risk Profile score. Further research is warranted to explore their role as potential therapeutic targets.

Association between atrial fibrillation and volumetric magnetic resonance imaging brain measures: Framingham Offspring Study

BACKGROUND

The increased risk of stroke and cognitive impairment associated with atrial fibrillation (AF) is well documented. However, there is a paucity of research investigating the relations between AF and brain morphology.

OBJECTIVE

The purpose of this study was to investigate the association between AF and brain volume measures on magnetic resonance imaging (MRI).

METHODS

The study sample included stroke- and dementia-free participants who attended the Framingham Heart Study offspring cohort 7th examination cycle (1999-2005) and underwent contemporaneous MRI. We examined the association between prevalent AF and brain volume measures (total cerebral volume, frontal lobe volume, temporal lobe volume, temporal horn volume, hippocampal volume, and white matter hyperintensity volume) with linear regression. We first adjusted models for age and sex, and then for vascular risk factors and APOE4.

RESULTS

We studied 2144 individuals (mean age 61.8 ± 9.3 years; 54% women); 73 participants (3.4%) had prevalent AF at the time of MRI. In age- and sex-adjusted models, AF was inversely associated with total cerebral brain volume, frontal brain volume, and temporal brain volume. After further adjustment for vascular risk factors and APOE4, AF remained associated with frontal brain volume.

CONCLUSION

After accounting for vascular risk factor burden, prevalent AF was associated with lobar indexes of vascular brain aging but not with expected white matter changes.

Plasma clusterin levels and risk of dementia, Alzheimer's disease, and stroke

INTRODUCTION

Genetic variation in the clusterin gene has been associated with Alzheimer Disease (AD), and the clusterin protein is thought to play a mechanistic role. We explored the associations of clusterin plasma levels with incident dementia, AD, and stroke.

METHODS

Plasma clusterin was assessed in 1532 nondemented participants from the Framingham Study Offspring cohort between 1998 and 2001 (mean age, 69 ± 6; 53% women). We related clusterin levels to risk of incident dementia, AD, and stroke using Cox-proportional hazards models and examined potential interactions.

RESULTS

A significant interaction of plasma clusterin levels with age was observed. Clusterin was significantly associated with increased risk of dementia among elderly persons (>80 years; hazard ratio [HR], 95% confidence interval = 6.25, 1.64-23.89; P = .007) and with decreased risk of dementia (HR = 0.53, 0.32-0.88; P = .013) and stroke (HR = 0.78, 0.63-0.97; P = .029) among younger participants.

DISCUSSION

The association between plasma clusterin levels and risk of dementia and stroke may be modified by age or an age-related factor.

Circulating vascular endothelial growth factor and the risk of cardiovascular events

OBJECTIVE

To investigate the relation of circulating concentrations of vascular endothelial growth factor (VEGF) for the risk of developing cardiovascular disease (CVD) in a large community-based sample.

METHODS

We prospectively assessed the relation of circulating VEGF concentrations with the incidence of CVD among 3041 Framingham Heart Study participants (mean age 63.4±11.1 years, 59% women). Multivariable Cox proportional hazards models were estimated adjusting for standard risk factors to VEGF quartiles to incident CVD. Restricted cubic splines were used to examine the linearity of the association.

RESULTS

After a mean follow-up of 8.8 (±2.8) years, 527 individuals experienced a first CVD event. Compared with participants in the first VEGF quartile, individuals in the second VEGF quartile had a 34% increased risk for future CVD (HR 1.34, 95% CI 1.03 to 1.74; p value=0.03) and individuals in third quartile had a 59% higher risk (HR 1.59; 95% CI 1.23 to 2.05, p value=0.0003). Individuals in the highest VEGF quartile had a similar cardiovascular risk as compared with those in the lowest VEGF quartile (HR 1.18, 95% CI 0.91 to 1.53, p value=0.21). Evaluation of restricted cubic splines confirmed the nonlinear, inverted U-shaped relation of serum VEGF and CVD events (p<0.0001 for model fit, p=0.006 for non-linearity).

CONCLUSIONS

Circulating VEGF concentrations exhibit a complex non-linear (inverted U-shaped) relation with the risk of developing CVD events, with the lowest risk experienced at the lower and upper end of the distribution. The underlying pathophysiological mechanisms remain to be elucidated.

Neck Circumference, Brain Imaging Measures, and Neuropsychological Testing Measures

BACKGROUND

Perivascular fat may have direct effects on local vascularity. Neck fat is associated with carotid intimal thickness, a predictor of brain aging outcomes. This study investigated whether neck circumference, an estimation of neck fat, has unique associations with brain aging outcomes.

METHODS

The study sample (n = 2082, 53.5% women, mean age 60.9 years) was derived from Framingham Heart Study participants with brain magnetic resonance imaging (MRI) and neuropsychological (NP) test measures. Multivariable-adjusted regressions examined cross-sectional associations of neck circumference with brain MRI and NP test measures. Models were also constructed with waist circumference and body mass index (BMI) as exposures.

RESULTS

A 1 standard deviation (2.8 cm [women]; 2.9 cm [men]) increment in neck circumference was associated with lower total cerebral brain volume (β = -.22, P = .0006) and lower frontal brain volume (β = -.55, P < .0001). However, a similar association was observed for both waist circumference and BMI. There were no associations between neck circumference and NP test measures after full covariate adjustment.

CONCLUSIONS

There were no unique associations between neck circumference and brain MRI or NP measures. Consistent with prior observations, all adiposity measures showed associations with more adverse brain MRI and NP measures, suggesting a global association of generalized adiposity.

Carotid Atherosclerosis and Cerebral Microbleeds: The Framingham Heart Study

BACKGROUND

Carotid atherosclerosis is associated with subclinical ischemic cerebrovascular disease, but its role in hemorrhage-prone small vessel disease-represented by cerebral microbleed (CMB)-is unclear, although vascular risk factors underlie both conditions. We hypothesized that persons with carotid atherosclerosis would have higher risk of CMB, particularly in deep regions.

METHODS AND RESULTS

We studied 1243 participants in the Framingham Offspring Study (aged 56.9±8.8 years; 53% women) with carotid ultrasound available on 2 occasions (1995-1998 and 2005-2008) prior to brain magnetic resonance imaging. Using multivariable logistic regression, we related baseline carotid stenosis, baseline intima-media thickness, and site-specific carotid intima-media thickness progression (at internal and common carotid locations) to the prevalence and location (lobar or deep plus mixed) of CMB. In addition, we assessed effect modification by lipid levels and use of statin and antithrombotic medications. Carotid stenosis ≥25% (a marker of cerebrovascular atherosclerosis) was associated with presence of CMB overall (Odds Ratio 2.20, 95% CI 1.10-4.40) and at deep and mixed locations (odds ratio 3.60, 95% CI 1.23-10.5). Baseline carotid intima-media thickness was not associated with CMB. Progression of common carotid artery intima-media thickness among persons on hypertension treatment was associated with lower risk of deep and mixed CMB (odds ratio per SD 0.41, 95% CI 0.18-0.96).

CONCLUSIONS

Cumulative vascular risk factor exposure may increase the risk of CMB, especially in deep regions. The apparent paradoxical association of carotid intima-media thickness progression with lower risk of CMB may reflect benefits of intensive vascular risk factor treatment among persons with higher cardiovascular risk and deserves further investigation. If replicated, the results may have potential implications for assessment of preventive and therapeutic interventions for subclinical cerebral hemorrhage.

Verbal memory and brain aging: an exploratory analysis of the role of error responses in the Framingham Study

OBJECTIVE

Analysis sought to determine whether Wechsler Memory Scale-Logical Memory (LM)-correct responses and errors were related to magnetic resonance imaging (MRI) brain volume measurements.

METHODS

The LM immediate (LM-I) and LM delay (LM-D) free recall correct responses and related and unrelated errors were scored. Principal components analysis yielded a 3-factor solution: LM-I and LM-D correct responses, LM-I and LM-D-unrelated errors, and LM-I/-D-related errors. The MRI total cerebral brain volume, frontal brain volume, temporal horn volume (THV), and white matter hyperintensities volume (WMHIV) were obtained.

RESULTS

Increasing THV (suggesting greater regional atrophy) was associated with lower scores on the LM-correct responses factor. Extensive WMHIV was associated with higher scores on the LM-related errors factor.

CONCLUSION

These results suggest that LM-correct responses could relate to emerging brain alterations. Longitudinal research might enhance the sensitivity of this test to identify preclinical impairment and persons at risk of mild cognitive impairment and dementia.

Associations of Circulating Growth Differentiation Factor-15 and ST2 Concentrations With Subclinical Vascular Brain Injury and Incident Stroke

BACKGROUND AND PURPOSE

Growth differentiation factor-15 (GDF-15) and soluble (s)ST2 are markers of cardiac and vascular stress. We investigated the associations between circulating concentrations of these biomarkers and incident stroke and subclinical vascular brain injury in a sample from the Framingham Offspring cohort.

METHODS

We followed 3374 stroke- and dementia-free individuals (mean age, 59.0±9.7 years; 53% women) attending the Framingham Offspring sixth examination cycle 11.8±3.0 years for incident stroke. A subsample of 2463 individuals underwent brain magnetic resonance imaging and neuropsychological testing ≈4.0±1.7 years after the sixth examination.

RESULTS

After adjustment for traditional cardiovascular risk factors, B-type natriuretic peptide, high-sensitivity C-reactive protein, and urine albumin levels, higher stress biomarker levels were associated cross-sectionally with lower brain volumes (β coefficients for intracranial volume comparing fourth [Q4] versus first biomarker [Q1] quartiles: -0.71% for GDF-15; P=0.002 and 0.47% for sST2; P=0.02) and worse performance on the visual reproduction test (β coefficients for Q4 versus Q1: -0.62 for GDF-15; P=0.009 and -0.40 for sST2; P=0.04). Higher GDF-15 concentrations were also associated with greater log-transformed white-matter hyperintensity volumes (β for Q4 versus Q1=0.19; P=0.01). Prospectively, a total of 203 (6%) individuals developed incident stroke/transient ischemic attack during follow-up. After multivariable adjustment, sST2 remained significantly associated with stroke/transient ischemic attack, hazard ratio for Q4 versus Q1 of 1.76, 95% confidence interval of 1.06 to 2.92, and P=0.03.

CONCLUSIONS

Circulating GDF-15 and sST2 are associated with subclinical brain injury and cognitive impairment. Higher sST2 concentrations are also associated with incident stroke, suggesting potential links between cardiac stress biomarkers and brain injury.

Long-term exposure to fine particulate matter, residential proximity to major roads and measures of brain structure

BACKGROUND AND PURPOSE

Long-term exposure to ambient air pollution is associated with cerebrovascular disease and cognitive impairment, but whether it is related to structural changes in the brain is not clear. We examined the associations between residential long-term exposure to ambient air pollution and markers of brain aging using magnetic resonance imaging.

METHODS

Framingham Offspring Study participants who attended the seventh examination were at least 60 years old and free of dementia and stroke were included. We evaluated associations between exposures (fine particulate matter [PM2.5] and residential proximity to major roadways) and measures of total cerebral brain volume, hippocampal volume, white matter hyperintensity volume (log-transformed and extensive white matter hyperintensity volume for age), and covert brain infarcts. Models were adjusted for age, clinical covariates, indicators of socioeconomic position, and temporal trends.

RESULTS

A 2-μg/m(3) increase in PM2.5 was associated with -0.32% (95% confidence interval, -0.59 to -0.05) smaller total cerebral brain volume and 1.46 (95% confidence interval, 1.10 to 1.94) higher odds of covert brain infarcts. Living further away from a major roadway was associated with 0.10 (95% confidence interval, 0.01 to 0.19) greater log-transformed white matter hyperintensity volume for an interquartile range difference in distance, but no clear pattern of association was observed for extensive white matter.

CONCLUSIONS

Exposure to elevated levels of PM2.5 was associated with smaller total cerebral brain volume, a marker of age-associated brain atrophy, and with higher odds of covert brain infarcts. These findings suggest that air pollution is associated with insidious effects on structural brain aging even in dementia- and stroke-free persons.

Circulating brain-derived neurotrophic factor concentrations and the risk of cardiovascular disease in the community

Background

Brain‐derived neurotrophic factor (BDNF) is a pleiotropic peptide involved in maintaining endothelial integrity. It is unknown if circulating BDNF levels are associated with risk of cardiovascular disease (CVD).

Methods and Results

We prospectively investigated the association of circulating BDNF levels with cardiovascular events and mortality in 3687 participants (mean age 65 years, 2068 women) from the Framingham Heart Study (FHS). Using a common nonsynonomous single nucleotide polymorphism (SNP) in the BDNF gene (rs6265), we then performed a Mendelian randomization experiment in the CARDIoGRAM (Coronary ARtery DIsease Genome‐Wide Replication And Meta‐Analysis) consortium (>22 000 coronary artery disease [CAD] cases, >60 000 controls) to investigate whether SNP rs6265 was associated with CAD in CARDIoGRAM and, if so, whether the effect estimate differed from that predicted based on FHS data. On follow‐up (median 8.9 years), 467 individuals (261 women) in FHS experienced a CVD event, and 835 (430 women) died. In multivariable‐adjusted Cox regression, serum BDNF was associated inversely with CVD risk (hazard ratio [HR] per 1‐SD increase 0.88, 95% CI 0.80 to 0.97, P=0.01) and with mortality (HR 0.87, 95% CI 0.80 to 0.93, P=0.0002). SNP rs6265 was associated with BDNF concentrations (0.772 ng/mL increase per minor allele copy) in FHS. In CARDIoGRAM, SNP rs6265 was associated with CAD (odds ratio 0.957, 95% CI 0.923 to 0.992), a magnitude consistent with the predicted effect (HR per minor allele copy 0.99, 95% CI 0.98 to 1.0; P=0.06 for difference between predicted and observed effect).

Conclusion

Higher serum BDNF is associated with a decreased risk of CVD and mortality. Mendelian randomization suggests a causal protective role of BDNF in the pathogenesis of CVD.

Abstract W P164: Cerebral Microbleeds and Physical performance: The Framingham Heart Study

Objective: To study the association of cerebral microbleeds (CMB) on MRI and physical performance in a community based cohort free of stroke and dementia.

Background: Impaired mobility and physical function are associated with increased morbidity and mortality. CMB are believed to be subclinical markers of hemorrhage-prone small vessel disease, but CMB-induced neuronal injury may promote physical impairment in individuals free of stroke and dementia by disrupting the complex cerebral pathways involved in gait control and balance.

Methods: We evaluated 1710 Framingham Offspring Study participants (mean age 64.6 years, 54% women) attending a baseline examination (1998-2008), who had brain MRI allowing for CMB detection and available measurements of physical performance. Walking speed was available in all, while a subset (N≈500) had available standing balance, chair standing and short physical battery scores. Using multivariable logistic regression we related CMB presence overall and stratified by brain location (lobar or deep) to the physical performance measures.

Results: CMB were observed in 7.7% of subjects. We observed an association of presence of any CMB with lower walking speed score (4 vs. <4) after adjustment for age, sex, time between MRI and study exam, and MRI markers of ischemic small vessel disease (OR 0.53, 95% CI 0.30-0.93, p=0.03). The association was no longer significant after adjusting for vascular risk factors (hypertension, diabetes, smoking, prevalent cardiovascular disease) instead of MRI markers (OR 0.63, 95% CI 0.36-1.11, p=0.11). There were no significant associations by CMB location and CMB were not associated with the remaining physical performance measures in the smaller samples.

Conclusions: CMB were associated with lower gait speed, a relation that was partly dependent on presence of vascular risk factors. Our findings are limited by the small sample in subgroups of CMB across physical performance measures other than gait speed, but if replicated in other studies, would suggest a negative impact of CMB on physical function in community dwelling persons without stroke or dementia. These findings are significant given longer life expectancy and increasing prevalence of CMB with age.

Abstract T P412: Cerebral Microbleeds and Cognition: The Framingham Heart Study

Objective: To study the association of cerebral microbleeds (CMB) on MRI and performance on a comprehensive neuropsychological test battery in a community based cohort free of stroke and dementia.

Background: CMB represent hemorrhage-prone cerebral small vessel disease (SVD) and have been related to increased risk of dementia. In non-demented individuals, CMB may negatively affect cognition and the pattern of impaired cognitive performance may differ according to lesion topography.

Methods: We evaluated 1744 Framingham Offspring Study participants (mean age 64.6 years, 54% women) attending a baseline examination (1998-2008), who had brain MRI allowing for CMB detection and underwent concurrent NP testing. Using multivariable linear regression we related CMB presence overall and stratified by brain location (lobar, deep or mixed) to performance on NP tests representing cognitive domains including memory, executive function, abstraction, language and visuospatial function.

Results: CMB were observed in 7.7% of subjects (66% lobar, 20% deep, 14% mixed). After adjustment for sex, age, level of education and MRI markers of ischemic small vessel disease, presence of any CMB was associated with impaired performance on tests of abstraction (β -0.71, p=0.02) and language (β -0.13, p=0.04). The associations were attenuated after adjustment for vascular risk factors (hypertension, diabetes, smoking, prevalent cardiovascular disease). Lobar CMB showed similar marginal associations (p=0.05), also attenuated after adjustment for vascular risk factors. Mixed location CMB were associated with tests of executive function, an association that remained significant after adjustment for MRI markers of ischemic SVD and vascular risk factors (β-0.12, p= 0.02). CMB in only deep location did not show any significant association with NP test performance.

Conclusions: CMB were associated with lower cognitive performance in a community-based sample of middle-aged adults. Our findings are limited given the cross sectional study design and small sample in subgroups of deep and mixed CMB, but concur with studies suggesting a negative impact of CMB on cognition, and expand prior studies by showing that the relations are independent of ischemic cerebral SVD.

Inflammatory biomarkers, cerebral microbleeds, and small vessel disease: Framingham Heart Study

OBJECTIVE

We investigated the association between circulating biomarkers of inflammation and MRI markers of small vessel disease.

METHODS

We performed a cross-sectional study relating a panel of 15 biomarkers, representing systemic inflammation (high-sensitivity C-reactive protein, interleukin-6, monocyte chemotactic protein-1, tumor necrosis factor α, tumor necrosis factor receptor 2, osteoprotegerin, and fibrinogen), vascular inflammation (intercellular adhesion molecule 1, CD40 ligand, P-selectin, lipoprotein-associated phospholipase A2 mass and activity, total homocysteine, and vascular endothelial growth factor), and oxidative stress (myeloperoxidase) to ischemic (white matter hyperintensities/silent cerebral infarcts) and hemorrhagic (cerebral microbleeds) markers of cerebral small vessel disease (CSVD) on MRI in 1,763 stroke-free Framingham offspring (mean age 60.2 ± 9.1 years, 53.7% women).

RESULTS

We observed higher levels of circulating tumor necrosis factor receptor 2 and myeloperoxidase in the presence of cerebral microbleed (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.1-4.1 and OR 1.5, 95% CI 1.1-2.0, respectively), higher levels of osteoprotegerin (OR 1.1, 95% CI 1.0-1.2), intercellular adhesion molecule 1 (OR 1.7, 95% CI 1.1-2.5), and lipoprotein-associated phospholipase A2 mass (OR 1.5, 95% CI 1.1-2.1), and lower myeloperoxidase (OR 0.8, 95% CI 0.7-1.0) in participants with greater white matter hyperintensity volumes and silent cerebral infarcts.

CONCLUSIONS

Our study supports a possible role for inflammation in the pathogenesis of CSVD, but suggests that differing inflammatory pathways may underlie ischemic and hemorrhagic subtypes. If validated in other samples, these biomarkers may improve stroke risk prognostication and point to novel therapeutic targets to combat CSVD.

Mid-adulthood risk factor profiles for CKD

Early identification of CKD risk factors may allow risk factor modification and prevention of CKD progression. We investigated the hypothesis that risk factors are present ≥30 years before the diagnosis of CKD in a case-control study using data from the Framingham Offspring Study. Patients with incident CKD (eGFR≤60 ml/min per 1.73 m2) at examination cycles 6, 7, and 8 were age- and sex-matched 1:2 to patients without CKD at baseline (examination 5). CKD risk factors were measured at each examination cycle. Logistic regression models, adjusted for age, sex, and time period, were constructed to compare risk factor profiles at each time point between cases and controls. During follow-up, 441 new cases of CKD were identified and matched to 882 controls (mean age 69.2 years, 52.4% women). Those who ultimately developed CKD were more likely to have hypertension (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.23 to 2.51), obesity (OR, 1.71; 95% CI, 1.14 to 2.59), and higher triglyceride levels (OR, 1.43; 95% CI, 1.12 to 1.83) 30 years before CKD diagnosis, and were more likely to have hypertension (OR, 1.38; 95% CI, 1.07 to 1.79), higher triglyceride levels (OR, 1.35; 95% CI, 1.11 to 1.64), lower HDLc (OR, 0.89; 95% CI, 0.81 to 0.97), and diabetes (OR, 2.90; 95% CI, 1.59 to 5.29) 20 years before CKD diagnosis. These findings demonstrate that risk factors for CKD are identifiable ≥30 years before diagnosis and suggest the importance of early risk factor identification in patients at risk for CKD.

Qualitative neuropsychological measures: normative data on executive functioning tests from the Framingham offspring study

BACKGROUND/STUDY CONTEXT: Studies have found that executive functioning is affected early in the pathophysiological processes associated with Alzheimer's disease and vascular dementia. There also exists a range of functioning on executive tasks during normal aging. Although qualitative data are commonly utilized in clinical practice for evaluating subtle changes in cognitive functioning and diagnostic discernment, it is not clear whether error responses used in clinical practice are also evident as normative behavior.

METHODS

As part of an extensive battery of neuropsychological tests, executive functioning measures (i.e., Trail Making Test Part B, Similarities and Verbal Fluency tests) were administered via standardized administration prescript. Regression analyses were used to determine associations between vascular aging indices and qualitative performance measures. Descriptive statistics are included for 1907 cognitively normal individuals.

RESULTS

Results suggest that although qualitative errors do occur, they are relatively infrequent within a presumably cognitively normal sample. Error commission rates on executive functioning tests are significantly associated with both age and education.

CONCLUSION

Provided is a baseline profile of errors committed on tests of executive function across a range of age and educational levels. The normative data sets are included, stratified by age and educational achievement, for which to compare qualitative test performance of clinical and research populations.

Cognitive performance after stroke--the Framingham Heart Study

BACKGROUND

Individuals with a high risk of stroke are also more prone to cognitive impairment perhaps because of concomitant vascular risk factors. In addition, clinical stroke increases the risk of subsequent dementia. Nevertheless, the relationship between clinical stroke and subsequent cognitive function in initially nondemented individuals remains less clear as most prior studies examined case series without controls.

AIMS

To specify among nondemented individuals the cognitive domains affected by clinical stroke, independently of vascular risk factors and prestroke cognition.

METHODS

One hundred thirty-two Framingham study participants (mean age = 77 ± 9 years, 54% women) with prospectively validated initial strokes, as well as age- and gender-matched controls, underwent identical cognitive evaluations ∼six-months after the stroke. Linear regression models were used to assess the differences in cognitive scores between stroke cases and controls adjusting for prestroke cognitive function as assessed by Mini-Mental State Examination scores, and with and without adjustment for vascular risk factors.

RESULTS

Adjusting for prestroke cognition and vascular risk factors, persons with stroke had poorer cognitive function in the domains of immediate recall of logical and visual memories (β = -1·27 ± 0·60, P = 0·035; β = -1·03 ± 0·47, P = 0·028, respectively), verbal learning (paired associate test; β = -1·31 ± 0·57, P = 0·023), language (Boston naming test; β = -0·27 ± 0·08, P = 0·002), executive function (digit span backward; β = -0·53 ± 0·21, P = 0·015), and visuospatial and motor skills (block design; β = -3·02 ± 1·06, P = 0·005).

CONCLUSIONS

Clinical stroke is associated with subsequent poorer performance in multiple cognitive domains. This association cannot be entirely explained by the individual's cognitive function prior to stroke or by concomitant vascular risk factor levels.

Risk factors, stroke prevention treatments, and prevalence of cerebral microbleeds in the Framingham Heart Study

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMBs) are associated with increased risk of stroke and poor cognition. Vascular risk factors and medications used for stroke prevention may increase the risk of CMB. We examined the prevalence of CMB and the association of these risk factors with CMB, postulating that risk factors for cerebral amyloid angiopathy would be associated with lobar CMB and markers of hypertensive vasculopathy with deep CMB.

METHODS

We include 1965 Framingham Original and Offspring participants (age, 66.5±11.0 years; 54% women) and evaluated the age- and sex-specific prevalence of CMB. We related various vascular and genetic (apolipoprotein E [APOE]) risk factors and medication use to the presence of CMB overall and stratified by brain location (deep, lobar, or mixed).

RESULTS

CMBs were observed in 8.8% of participants, being mostly lobar (63%). CMB prevalence increased with age (P<0.0001) and was higher in men (P<0.001). Hypertension increased risk of any CMB, and in deep and mixed locations (P<0.05), and low total cholesterol and APOE ε4 increased risk of lobar CMB (P<0.05). Statin use increased risk of lobar and mixed location CMB (P<0.05). The latter association was not affected by adjustment for cholesterol levels or concomitant medication use.

CONCLUSIONS

We observed the expected association of hypertension with deep CMB and low cholesterol and APOE ε4 with lobar CMB. In addition, statin use was independently associated with CMB risk. This potential adverse effect of statin use needs to be examined in other cohorts.

Serum brain-derived neurotrophic factor and the risk for dementia: the Framingham Heart Study

IMPORTANCE

In animal studies, brain-derived neurotrophic factor (BDNF) has been shown to impact neuronal survival and function and improve synaptic plasticity and long-term memory. Circulating BDNF levels increase with physical activity and caloric restriction, thus BDNF may mediate some of the observed associations between lifestyle and the risk for dementia. Some prior studies showed lower circulating BDNF in persons with Alzheimer disease (AD) compared with control participants; however, it remains uncertain whether reduced levels precede dementia onset.

OBJECTIVE

To examine whether higher serum BDNF levels in cognitively healthy adults protect against the future risk for dementia and AD and to identify potential modifiers of this association.

DESIGN, SETTING, AND PARTICIPANTS

Framingham Study original and offspring participants were followed up from 1992 and 1998, respectively, for up to 10 years. We used Cox models to relate BDNF levels to the risk for dementia and AD and adjusted for potential confounders. We also ran sensitivity analyses stratified by sex, age, and education, as well as related BDNF genetic variants to AD risk. This community-based, prospective cohort study involved 2131 dementia-free participants aged 60 years and older (mean [SD] age, 72 [7] years; 56% women).

MAIN OUTCOMES AND MEASURES

Ten-year incidence of dementia and AD.

RESULTS

During follow-up, 140 participants developed dementia, 117 of whom had AD. Controlling for age and sex, each standard-deviation increment in BDNF was associated with a 33% lower risk for dementia and AD (P = .006 and P = .01, respectively) and these associations persisted after additional adjustments. Compared with the bottom quintile, BDNF levels in the top quintile were associated with less than half the risk for dementia and AD (hazard ratio, 0.49; 95% CI, 0.28-0.85; P = .01; and hazard ratio, 0.46; 95% CI, 0.24-0.86; P = .02, respectively). These associations were apparent only among women, persons aged 80 years and older, and those with college degrees (hazard ratios for AD: 0.65, [95% CI, 0.50-0.85], P = .001; 0.63 [95% CI, 0.47-0.85], P = .002; and 0.27 [95% CI, 0.11-0.65], P = .003, respectively). Brain-derived neurotrophic factor genetic variants were not associated with AD risk.

CONCLUSIONS AND RELEVANCE

Higher serum BDNF levels may protect against future occurrence of dementia and AD. Our findings suggest a role for BDNF in the biology and possibly in the prevention of dementia and AD, especially in select subgroups of women and older and more highly educated persons.

Abstract W MP55: Inflammatory Biomarkers and Incident Stroke in the Framingham Offspring Study

Background: Inflammatory cascades are believed to be involved in pathogenesis of small vessel disease and atherothrombosis. We related a comprehensive panel of inflammatory biomarkers to risk of incident ischemic stroke (IS) in a community-dwelling sample

Methods: Stroke-free Framingham Offspring attending exam cycle 7 (1998-2001) had multiple serum inflammatory biomarkers measured. Fourteen biomarkers representing various components of the inflammatory cascade, including systemic inflammation (C-reactive protein [CRP], interleukin-6, monocyte chemotactic protein 1, tumor necrosis factor-α, tumor necrosis factor receptor 2 [TNFr2], osteoprotegerin and fibrinogen), vascular inflammation (intercellular adhesion molecule-1, CD40 ligand, P-selectin, lipoprotein-associated phospholipase A2 mass and activity, total homocysteine [tHcy] and vascular endothelial growth factor [VEGF]) and oxidative stress (myeloperoxidase) were selected. Cox proportional hazard models were used to relate individual biomarkers to risk of incident IS. Model A included age and sex. Model B additionally adjusted for systolic blood pressure, hypertension treatment, current smoking, diabetes, cardiovascular disease, and atrial fibrillation. Hazard ratios (HR) are presented as per 1 SD increment.

Results: In 3224 participants (age: 61±9 years, 54% women), 98 experienced incident IS (mean follow-up of 9.8 [±2.2] years). In Model A, log-CRP (HR: 1.28 [95%CI 1.04-1.56]), log-TNFR2 (HR: 1.33 [95%CI 1.09-1.63]), tHcy (HR: 1.32 [95%CI 1.11-1.58]) and VEGF (HR: 1.25 [95%CI 1.07-1.46]) were associated with risk of incident IS. All associations, except for CRP, remained significant in Model B {log-TNFR2 (1.24 [1.02-1.51]), tHcy (1.20 [1.01-1.43]), VEGF (1.21 [1.04-1.42]) and CRP (1.13 [0.92-1.40])}. Addition of these 4 biomarkers to the clinical Framingham Stroke Risk Profile score improved stroke risk prediction (net reclassification improvement: 0.34; p<0.05 using boundaryless models).

Conclusions: Higher levels of four biomarkers: CRP, tHcy, TNFR2 and VEGF increased risk of incident ischemic stroke. Further research is required to confirm their utility in improving stroke risk prediction, and explore their role as potential therapeutic targets.

Development and validation of a brief dementia screening indicator for primary care

BACKGROUND

Detection of "any cognitive impairment" is mandated as part of the Medicare annual wellness visit, but screening all patients may result in excessive false positives.

METHODS

We developed and validated a brief Dementia Screening Indicator using data from four large, ongoing cohort studies (the Cardiovascular Health Study [CHS]; the Framingham Heart Study [FHS]; the Health and Retirement Study [HRS]; the Sacramento Area Latino Study on Aging [SALSA]) to help clinicians identify a subgroup of high-risk patients to target for cognitive screening.

RESULTS

The final Dementia Screening Indicator included age (1 point/year; ages, 65-79 years), less than 12 years of education (9 points), stroke (6 points), diabetes mellitus (3 points), body mass index less than 18.5 kg/m(2) (8 points), requiring assistance with money or medications (10 points), and depressive symptoms (6 points). Accuracy was good across the cohorts (Harrell's C statistic: CHS, 0.68; FHS, 0.77; HRS, 0.76; SALSA, 0.78).

CONCLUSIONS

The Dementia Screening Indicator is a simple tool that may be useful in primary care settings to identify high-risk patients to target for cognitive screening.