Joseph F Polak

Joseph F Polak
Tufts Medical Center · Department of Radiology

MD, MPH

About

513
Publications
33,756
Reads
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38,314
Citations
Additional affiliations
October 2003 - present
Tufts Medical Center
Position
  • Radiologist
October 2003 - present
Tufts Medical Center
Position
  • Professor of Radiology
October 2003 - present
Lemuel Shattuck Hospital
Lemuel Shattuck Hospital
Position
  • Chief of Radiology

Publications

Publications (513)
Article
Full-text available
Background The major risk factors for atherosclerotic cardiovascular disease differ by race or ethnicity but have largely been defined using populations of European ancestry. Despite the rising prevalence of cardiovascular disease in Africa there are few related data from African populations. Therefore, we compared the association of established ca...
Article
Background: Carotid atherosclerosis is associated with cognitive impairment and dementia, though there is limited evidence of a direct link between carotid disease and amyloid-β (Aβ) burden. Objective: We studied the association of baseline and progressive carotid intima media thickness (CIMT) with Aβ on 11C-Pittsburgh Compound B (PiB) to determ...
Article
BACKGROUND: IL-6 (interleukin-6) has important roles in atherosclerosis pathophysiology. To determine if anti-IL-6 therapy warrants evaluation as an adjuvant stroke prevention strategy in patients with carotid atherosclerosis, we tested whether circulating IL-6 levels predict carotid plaque severity, vulnerability, and progression in the prospectiv...
Article
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Background Carotid artery intima‐media thickness (IMT) is associated with the risk of subsequent cardiovascular events in the general population. This association has not been established in type 1 diabetes. Methods and Results We studied if carotid IMT is associated with the risk of a first coronary artery disease event in participants with type...
Article
The long-term prognostic significance of a coronary artery calcium (CAC) score of 0 is poorly defined in younger adults. We evaluated this among participants aged 45 to 55 years from the Multi-Ethnic Study of Atherosclerosis, and assessed whether additional biomarkers can identify subgroups at increased absolute risk. We included 1,407 participants...
Article
Carotid intima media thickness (cIMT) is a biomarker of subclinical atherosclerosis and a predictor of future cardiovascular events. Identifying associations between gene expression levels and cIMT may provide insight to atherosclerosis etiology. Here, we use two approaches to identify associations between mRNA levels and cIMT: differential gene ex...
Article
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Backgrounds and aims: Elevated common carotid artery intima-media thickness (carotid IMT) and diminished flow-mediated dilation (FMD) are early subclinical indicators of atherosclerosis. Serum total non-esterified fatty acid (NEFA) concentrations have been positively associated with subclinical atherosclerosis. The relations between individual NEFA...
Article
Objectives Carotid artery intima-media thickness (CIMT) has been used as an early indicator of subclinical atherosclerosis. Multiple studies have identified significant associations between plasma total non-esterified fatty acid (NEFA) concentrations and risk factors associated with subclinical atherosclerosis. However, the relationship between CIM...
Article
Increased carotid intima-media thickness (cIMT) is associated with heart failure (HF) in previous studies, but it is not known whether the association of cIMT differs between HF with reduced (HFrEF) versus preserved ejection fraction (HFpEF). We studied 6699 participants (mean age 62 ± 10 years, 47% male, and 38% white) from the Multi-Ethnic Study...
Article
Full-text available
Objectives The purpose of this study was to identify predictors of healthy arterial aging (long-term coronary artery calcification [CAC] of 0) among individuals with metabolic syndrome (MetS) or type 2 diabetes (T2D), which may improve primary prevention strategies. Background Individuals with MetS or T2D have a heterogeneously increased risk of a...
Article
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Introduction: We studied the association of carotid intima-media thickness (CIMT) with hippocampal volume (HV) in community dwelling individuals, testing the hypothesis that persons with carotid atherosclerosis progression would have lower HV. Methods: We studied 1376 Framingham Offspring participants with two carotid ultrasounds and brain magne...
Article
Full-text available
Aims Averaged measurements, but not the progression based on multiple assessments of carotid intima-media thickness, (cIMT) are predictive of cardiovascular disease (CVD) events in individuals. Whether this is true for conventional risk factors is unclear. Methods and results An individual participant meta-analysis was used to associate the annual...
Article
Distal (near bifurcation) common carotid artery (CCA) peak systolic velocity (PSV) values are lower than near the origin (proximal). We investigate whether this applies to patients with internal carotid artery (ICA) stenosis ≥ 50% (PSV ≥ 125 cm/s). We studied 328 patients. We excluded carotid arteries with CCA stenosis and carotid endarterectomy. W...
Article
The association between internal carotid artery/peak systolic velocity and stenosis severity as measured by the North American Symptomatic Carotid Endarterectomy Trial is known. The association of internal carotid artery peak systolic velocity to common carotid artery peak systolic velocity ratio is less well studied. We use a machine learning algo...
Article
Full-text available
This study investigated the relationship between ankle–brachial index (ABI) and risk for heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). ABI has previously been associated with mortality, cardiovascular disease (CVD), and overall HF but the relationship between ABI and risk of HF stratified by EF has no...
Article
Background and aims: Fibroblast growth factor 21 (FGF21) has been suggested as a novel biomarker for cardiovascular disease (CVD), especially in people with high CVD risk. However, it is not known whether FGF21 is a CVD biomarker in an initially healthy cohort. We therefore investigated the relationship of plasma FGF21 levels with measures of subc...
Article
Objectives We compared internal carotid artery Doppler peak systolic velocities (PSVs) measured with angle correction parallel to the artery wall (// wall) on grayscale images and parallel to the direction of blood flow (// flow) on color Doppler images. Methods We studied 25 internal carotid lesions with PSVs higher than 125 cm/s. The PSVs were m...
Article
Nonalcoholic fatty liver disease (NAFLD) is considered a potential independent risk factor for cardiovascular disease (CVD). The Multi-Ethnic Study of Atherosclerosis cohort enrolled 6,814 adults without previous CVD. We excluded 2,692 participants who had missing variables, were heavy drinkers, or history of steroid use and/or chronic liver diseas...
Article
Full-text available
Common carotid artery (CCA) intima-media thickness (IMT) is associated with coronary heart disease and can be measured on ultrasound images either by hand or with an automated edge detector. The association of CCA IMT with incident peripheral artery disease (PAD) is poorly studied. We studied 5467 participants of the Multi-Ethnic Study of Atheroscl...
Article
Full-text available
Background Brachial artery reactivity (BAR) is usually determined as the maximum brachial artery diameter (BAD) following release of an occluding pressure cuff compared to a BAD before cuff inflation. BAD early after cuff deflation can also serve as baseline for estimating total brachial artery reactivity (TBAR). We investigate whether TBAR is asso...
Article
Objectives: This study sought to determine the relationship between coronary artery calcium (CAC) scores and subsequent cardiovascular disease (CVD) events in DCCT (Diabetes Control and Complications Trial)/EDIC (Epidemiology of Diabetes Interventions and Complications) participants. Background: The CAC score has been validated for improved risk...
Article
Background: Carotid atherosclerosis is a known risk factor for stroke and dementia. Carotid atherosclerosis may play a role in neurodegeneration and be a potential target for treatment and preventive efforts for stroke and dementia in asymptomatic individuals. We studied the association of carotid intima media thickness (CIMT) with hippocampal volu...
Article
Background and aims: The extent and relation of multisite atherosclerosis to cardiovascular disease (CVD) in metabolic syndrome (MetS) and diabetes (DM) are not well documented. We examined the extent of multisite atherosclerosis and its prognostic value for CVD events in MetS and DM. Methods: In CVD-free subjects from the Multi-Ethnic Study of...
Article
Full-text available
Purpose To compare common carotid artery (CCA) wall thickness measured manually by using US and semiautomatically by using MRI, and to examine their associations with incident coronary heart disease and stroke. Materials and Methods This prospective study enrolled 698 participants without a history of clinical cardiovascular disease (CVD) from the...
Article
Background: Current guidelines suggest treatment for many individuals who may never develop a stroke. We hypothesized that a combination of coronary artery calcification (CAC) and carotid artery intima-media thickness (C IMT) data could better individualize risk assessment for ischemic stroke and transient ischemic attack events. Methods: A tota...
Article
Background and aims: The association between minimally elevated coronary artery calcification (CAC) and cerebrovascular disease is not well known. We assessed whether individuals with minimal CAC (Agatston scores of 1-10) have higher ischemic stroke or transient ischemic attack (TIA) frequencies compared with those with no CAC. We also investigate...
Article
Full-text available
Aims Carotid intima media thickness (CIMT) predicts cardiovascular (CVD) events, but the predictive value of CIMT change is debated. We assessed the relation between CIMT change and events in individuals at high cardiovascular risk. Methods and results From 31 cohorts with two CIMT scans (total n = 89070) on average 3.6 years apart and clinical fo...
Data
Data sharing restrictions, availability and contacts by study. (PDF)
Data
Meta-regression plots for the HR (combined endpoint) per SD of annual mean CCA-IMT change, by the year of the study start for group A cohorts. The size of each circle represents the precision of the log HR. Left panel: Model 1 (HR adjusted for age, sex, and average mean CCA-IMT): weighted regression line y = 7.07+0.004*x (p = 0.34). Right panel: Mo...
Data
Distribution of average mean CCA-IMT, annual change of mean CCA-IMT, and crude event rates by cohort and subgroup. *mean CCA-IMT not available, maximal CCA-IMT used instead. &combined endpoint not available, total mortality used instead. (DOCX)
Data
Forest plots of the HR of total mortality in group A (asymptomatic individuals with three or more CVD risk factors) with 95% Cls. Left panel: HR for total mortality per one SD of annual mean CCA-IMT change, adjusted for age, sex and average mean CCA-IMT (model 1). Right panel: HR for total mortality per one SD of average mean CCA-IMT, adjusted for...
Data
Forest plots of the HR of the combined endpoint in group A (asymptomatic individuals with three or more CVD risk factors) for maximal CCA-IMT with 95% Cls. Left panel: HR for the combined endpoint per one SD of annual maximal CCA-IMT change, adjusted for age, sex and average maximal CCA-IMT (model 1). Right panel: HR for the combined endpoint per o...
Data
Study-specific details of the ultrasound protocols. +plaques purposely included. #internal landmarks in computer aided navigation aid. ++2D images extracted from 3D dataset. n.s. = not specified. (DOCX)
Data
Flowchart on available studies. (DOCX)
Data
Forest plots of the HR of the combined endpoint per one SD of annual mean CCA-IMT change, grouped by IMT measurement protocol, with 95% Cls. Group B (asymptomatic individuals with carotid plaques), HR adjusted for age, sex and average mean CCA-IMT (model 1). (DOCX)
Article
Background and aims: The prevalence and correlates of subclinical atherosclerosis when low-density lipoprotein cholesterol (LDL-C) levels are low remain unclear. Therefore, we examined the association of cardiovascular risk factors and subclinical atherosclerosis among individuals with untreated LDL-C <70 mg/dL. Methods: We included participants...
Article
Background: Previous studies show that Hispanic persons have similar or lower levels of coronary artery calcium (CAC) and slower progression than non-Hispanic whites (NHW), even after adjustment for traditional risk factors. We examined whether this health advantage in CAC incidence and progression among Hispanic adults extends across all levels of...
Article
Full-text available
Minimum variance (MV) adaptive beamforming, which adaptively estimates and suppresses interfering signals, has attracted increased attention for ultrasound imaging in recent years. While many MV algorithms have been applied to ultrasound, these algorithms generally rely on signal models that neglect amplitude differences across the array due to ele...
Article
Full-text available
Aims: Carotid intima media thickness (CIMT) predicts cardiovascular (CVD) events, but the predictive value of CIMT change is debated. We assessed the relation between CIMT change and events in individuals at high cardiovascular risk. Methods and Results: From cohorts with two CIMT scans on average 3.6 years apart and clinical follow-up, subcohorts...
Article
Background -The causal role of high density lipoprotein (HDL) cholesterol in cardioprotection has been questioned by genetic and randomized studies. Novel measures that relate to HDL function may contribute new information to prediction of cardiovascular risk. Apolipoprotein C-III (apoC-III) is a key regulator of lipoprotein metabolism. We investi...
Article
Full-text available
Objective To determine if hepatocyte growth factor (HGF), a promising biomarker of coronary heart disease (CHD) given its release into circulation in response to endothelial damage, is associated with subclinical and clinical CHD in a racial/ethnic diverse population. Methods HGF was measured in 6738 participants of the Multi-Ethnic Study of Ather...
Article
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Background: Plasminogen activator inhibitor type 1 (PAI-1) plays an essential role in the fibrinolysis system and thrombosis. Population studies have reported that blood PAI-1 levels are associated with increased risk of coronary heart disease (CHD). However, it is unclear whether the association reflects a causal influence of PAI-1 on CHD risk....
Article
Full-text available
Aims: Epidemiological evidence indicates a protective effect of light to moderate alcohol consumption compared to non-drinking and heavy drinking. Although several mechanisms have been suggested, the effect of alcohol on atherosclerotic changes in vessel walls is unclear. Therefore, we explored the relationship between alcohol consumption and comm...
Article
Full-text available
Hypertension is a leading cause of global disease, mortality, and disability. While individuals of African descent suffer a disproportionate burden of hypertension and its complications, they have been underrepresented in genetic studies. To identify novel susceptibility loci for blood pressure and hypertension in people of African ancestry, we per...
Data
Discovery stage results and linkage disequilibrium maps of the candidate regions. (PDF)
Data
Enrichment for functional annotations of variants in 11 replicated loci reaching genome-wide significance. (PDF)
Data
Genotyping, pre-imputation quality control, imputation and analysis methods in the participating studies. (PDF)
Data
Quantile-quantile plots for both individual traits and CPASSOC analysis in discovery stage. (PDF)
Data
Manhattan plots of single trait and CPASSOC analyses at the discovery stage. (PDF)
Data
Genomic inflation factors by study and analysis. (PDF)
Data
Summary of iHS signals in significant loci with frequency differences across ancestry populations. (PDF)
Data
Descriptive characteristics of the discovery studies. (PDF)
Data
Conditional analysis of SNPs with P < 1.0 × 10−6 in discovery stage for SBP, DBP, PP, HTN or CPASSOC analysis. (PDF)
Data
72 Independent SNPs with P < 1.0 × 10−6 in discovery stage for SBP, DBP, PP, HTN or CPASSOC analysis. (PDF)
Data
Trans-ethnic replication of 72 independent SNPs with P < 1.0 × 10−6 in discovery stage for SBP, DBP, PP, HTN or CPASSOC. (PDF)
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Regional interrogation of the HOXA/EVX1, ULK4 and PLEKHG1. (PDF)
Data
eQTL analysis of significant SNPs in tissues. (PDF)
Data
Primes for mouse expression experiments. (PDF)
Data
Single-trait and multi-trait genome wide association analyses identify novel loci for blood pressure in African-ancestry populations. (DOCX)
Article
Full-text available
Background The relation of a single risk factor with atherosclerosis is established. Clinically we know of risk factor clustering within individuals. Yet, studies into the magnitude of the relation of risk factor clusters with atherosclerosis are limited. Here, we assessed that relation. Methods Individual participant data from 14 cohorts, involvi...
Data
Relation between risk factor clusters and CIMT (by sex). Each cluster was compared to individuals without any risk factor (reference group). CIMT, mean common carotid intima media thickness. BP, elevated blood pressure; OW, overweight; TC, elevated total cholesterol; smoking, current smoking. (TIF)
Data
Relation between risk factor clusters and CIMT (by race-ethnic group). Each cluster was compared to individuals without any risk factor (reference group). CIMT, mean common carotid intima media thickness. BP, elevated blood pressure; OW, overweight; TC, elevated total cholesterol; smoking, current smoking. (TIF)
Article
Introduction: Hepatocyte growth factor (HGF) is released in response to endothelial injury, and higher levels of circulating HGF are associated with atherosclerosis. However, the association of HGF with atherosclerosis progression is unknown. Hypothesis: Circulating HGF is positively associated with atherosclerosis progression, measured as progress...
Article
Full-text available
Objective: Albuminuria is a marker for subclinical cardiovascular disease (CVD) in the general population. It is uncertain whether this association is present in patients with rheumatoid arthritis (RA), a population with increased atherosclerosis and CVD events. Methods: Urine albumin from a spot morning collection was measured, and the urine al...
Data
Table S1. Risk Factor‐Adjusted Cox Regression Models for Predicting Incident Events With Multiple Imputation
Article
Full-text available
Background Coronary artery calcium (CAC) predicts coronary heart disease (CHD) events better than carotid wall plaque presence; however, differences in the utility of CAC burden and carotid plaque burden across the spectrum of cardiovascular disease (CVD) events is unknown. Methods and Results CVD, CHD and stroke/transient ischemic attack (TIA) ev...