Search tips
Search criteria

Results 1-10 (10)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Cardiovascular Epidemiology in a Changing World—Challenges to Investigators and the National Heart, Lung, and Blood Institute 
American Journal of Epidemiology  2012;175(7):597-601.
Over the past 60 years, revolutionary discoveries made by epidemiologists have contributed to marked declines in cardiovascular disease morbidity and mortality. Now, in an era of increasingly constrained resources, researchers in cardiovascular epidemiology face a number of challenges that call for novel, paradigm-shifting approaches. In this paper, the authors pose to the community 4 critical questions: 1) How can we avoid wasting resources on studies that provide little incremental knowledge? 2) How can we assure that we direct our resources as economically as possible towards innovative science? 3) How can we be nimble, responding quickly to new opportunities? 4) How can we identify prospectively the most meritorious research questions? Senior program staff at the National Heart, Lung, and Blood Institute invite the epidemiology community to join them in an ongoing Web-based blog conversation so that together we might develop novel approaches that will facilitate the next generation of high-impact discoveries.
PMCID: PMC3390031  PMID: 22415032
cardiovascular diseases; epidemiology; National Institutes of Health (U.S.); research
2.  Distribution of Coronary Artery Calcium Scores by Framingham 10-Year Risk Strata in the Multi-Ethnic Study of Atherosclerosis (MESA): Potential Implications for Coronary Risk Assessment 
By examining the distribution of CAC across FRS strata in a large, multi-ethnic, community-based sample of men and women, we sought to determine if lower risk persons could potentially benefit from CAC screening.
The 10-year Framingham risk scores (FRS) and coronary artery calcium (CAC) are predictors of coronary heart disease (CHD). CAC ≥300 is associated with the highest risk for CHD even in low risk (FRS <10%) persons; however expert groups have suggested CAC screening only in intermediate risk (FRS 10–20%) groups.
We included 5660 MESA participants. The number needed to screen [number of people that need to be screened to detect one person with CAC above the specified cut-point (NNS)] was used to assess the yield of screening for CAC. CAC prevalence was compared across FRS strata using chi-square tests.
CAC >0, ≥100 and ≥300 were present in 46.4%, 20.6% and 10.1% of participants, respectively. Prevalence and amount of CAC increased with higher FRS. CAC ≥300 was observed in 1.7% and 4.4% of those with FRS 0–2.5% and 2.6–5%, respectively (NNS =59.7 and 22.7). Likewise, CAC ≥300 was observed in 24% and 30% of those with FRS 15.1–20% and >20%, respectively (NNS =4.2 and 3.3). Trends were similar when stratified by age, gender and race/ethnicity.
Our study suggests that in very low risk individuals (FRS ≤5%), the yield of screening and probability of identifying persons with clinically significant levels of CAC is low, but becomes greater in low and intermediate risk persons (FRS 5.1–20%).
PMCID: PMC3268231  PMID: 21527159
Framingham risk score; coronary calcium; coronary heart disease; number needed to screen; risk factors; population; atherosclerosis; low risk
3.  Alcohol and coronary artery calcium prevalence, incidence and progression: results from the Multi-Ethnic Study of Atherosclerosis (MESA) 
Alcohol use has been consistently found to have a J-shaped association with coronary heart disease, with moderate drinkers exhibiting a decreased risk compared to both heavy drinkers and non-drinkers. However, studies of the association between alcohol use and subclinical coronary artery disease have conflicted.
To determine whether alcohol is associated with the presence, amount, or progression of coronary calcium over a 2- to 4-year period.
MESA is a prospective community-based cohort study of subclinical cardiovascular disease in a multi-ethnic cohort. In 2000–2002, 6814 participants free of clinical cardiovascular disease were enrolled at 6 participating centers.
There were 3766 (55.5%) current drinkers, 1635 (24.1%) former drinkers, and 1390 (20.5%) never drinkers included in the analysis. Although light to moderate alcohol consumption was associated with lower coronary heart disease risk, we found no evidence of a protective or J-shaped association of alcohol and coronary artery calcium (CAC). In fact there was evidence that heavy consumption of hard liquor was associated with greater CAC accumulation. Other alcoholic beverages were not associated with CAC prevalence, incidence or progression.
This is the first large study to evaluate the association of alcohol and coronary artery calcium in four racial/ethnic groups, and to evaluate progression of calcification. These results suggest that the cardiovascular benefits that may be derived from light to moderate alcohol consumption are not mediated through reduced CAC accumulation.
PMCID: PMC3319440  PMID: 19064520
4.  Cardiovascular Imaging for Assessing Cardiovascular Risk in Asymptomatic Men Versus Women 
Coronary artery calcium (CAC), carotid intima-media thickness, and left ventricular (LV) mass and geometry offer the potential to characterize incident cardiovascular disease (CVD) risk in clinically asymptomatic individuals. The objective of the study was to compare these cardiovascular imaging measures for their overall and sex-specific ability to predict CVD.
Methods and Results
The study sample consisted of 4965 Multi-Ethnic Study of Atherosclerosis participants (48% men; mean age, 62±10 years). They were free of CVD at baseline and were followed for a median of 5.8 years. There were 297 CVD events, including 187 coronary heart disease (CHD) events, 65 strokes, and 91 heart failure (HF) events. CAC was most strongly associated with CHD (hazard ratio [HR], 2.3 per 1 SD; 95% CI, 1.9 to 2.8) and all CVD events (HR, 1.7; 95% CI, 1.5 to 1.9). Most strongly associated with stroke were LV mass (HR, 1.3; 95% CI, 1.1 to 1.7) and LV mass/volume ratio (HR, 1.3; 95% CI, 1.1 to 1.6). LV mass showed the strongest association with HF (HR, 1.8; 95% CI, 1.6 to 2.1). There were no significant interactions for imaging measures with sex and ethnicity for any CVD outcome. Compared with traditional risk factors alone, overall risk prediction (C statistic) for future CHD, HF, and all CVD was significantly improved by adding CAC, LV mass, and CAC, respectively (all P<0.05).
There was no evidence that imaging measures differed in association with incident CVD by sex. CAC was most strongly associated with CHD and CVD; LV mass and LV concentric remodeling best predicted stroke; and LV mass best predicted HF.
PMCID: PMC3037859  PMID: 21068189
imaging; cardiovascular diseases; sex
5.  The Impact of Obesity on the Left Ventricle 
JACC. Cardiovascular imaging  2010;3(3):266-274.
The purpose of this study was to evaluate the relationship of left ventricular (LV) remodeling assessed by cardiac magnetic resonance to various measures of obesity in a large population-based study.
Obesity is a well-known risk factor for cardiovascular disease, yet its relationship with LV size and function is poorly understood.
A total of 5,098 participants (age 45 to 84 years; 48% men) in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cardiovascular disease underwent cardiac magnetic resonance to assess LV size and function as well as measures of obesity, including body mass index, waist-to-hip ratio and waist circumference, and cardiovascular risk factors. Fat mass (FM) was estimated based on height-weight models derived from bioelectrical impedance studies. The associations of obesity measures with LV size and function were evaluated using linear spline regression models for body mass index and multivariable regression models for other measures of obesity; they were displayed graphically using generalized additive models.
LV mass and end-diastolic volume were positively associated with measures of obesity in both sexes after adjustment for risk factors (e.g., 5.7-g and 6.9-g increase in LV mass per 10-kg increase in FM in women and men, respectively [p < 0.001]). LV mass-to-volume ratio was positively associated with increased body mass index, waist-to-hip ratio, waist circumference, and estimated FM (e.g., 0.02-g/ml and 0.06-g/ml increase in mass-to-volume ratio per 10-kg increase in FM in women and men, respectively [p < 0.001]). The increased mass-to-volume ratio was due to a greater increase in LV mass relative to LV end-diastolic volume. All associations were stronger for men than for women. Ejection fraction showed no significant association with measures of obesity.
Obesity was associated with concentric LV remodeling without change in ejection fraction in a large, multiethnic cohort study.
PMCID: PMC3037096  PMID: 20223423
cardiac magnetic resonance; cardiac morphology; epidemiology; left ventricular function; obesity
6.  Coronary Artery Calcium Score and Risk Classification for Coronary Heart Disease Prediction: The Multi-Ethnic Study of Atherosclerosis 
Coronary artery calcium score (CACS) has been shown to predict future coronary heart disease (CHD) events. However, the extent to which adding CACS to traditional CHD risk factors improves classification of risk is unclear.
To determine whether adding CACS to a prediction model based on traditional risk factors improves classification of risk.
Design, Setting and Participants
CACS was measured by computed tomography on 6,814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort without known cardiovascular disease. Recruitment spanned July 2000 to September 2002; follow-up extended through May 2008. Participants with diabetes were excluded for the primary analysis. Five-year risk estimates for incident CHD were categorized as 0-<3%, 3-<10%, and ≥10% using Cox proportional hazards models. Model 1 used age, gender, tobacco use, systolic blood pressure, antihypertensive medication use, total and high-density lipoprotein cholesterol, and race/ethnicity. Model 2 used these risk factors plus CACS. We calculated the net reclassification improvement (NRI) and compared the distribution of risk using Model 2 versus Model 1.
Main Outcome Measures
Incident CHD events
Over 5.8 years median follow-up, 209 CHD events occurred, of which 122 were myocardial infarction, death from CHD, or resuscitated cardiac arrest. Model 2 resulted in significant improvements in risk prediction compared to Model 1 (NRI=0.25, 95% confidence interval 0.16-0.34, P<0.001). With Model 1, 69% of the cohort was classified in the highest or lowest risk categories, compared to 77% with Model 2. An additional 23% of those who experienced events were reclassified to high risk, and an additional 13% without events were reclassified to low risk using Model 2.
In the MESA cohort, addition of CACS to a prediction model based on traditional risk factors significantly improved the classification of risk and placed more individuals in the most extreme risk categories.
PMCID: PMC3033741  PMID: 20424251
7.  The Association Between A1C and Subclinical Cardiovascular Disease 
Diabetes Care  2009;32(9):1727-1733.
To test the hypothesis that A1C is associated with subclinical cardiovascular disease (CVD) in a population without evident diabetes, after adjusting for traditional CVD risk factors and BMI.
This was a cross-sectional study of 5,121 participants without clinically evident CVD or diabetes (fasting glucose ≥7.0 mmol/l or use of diabetes medication), aged 47–86 years, enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). Measurements included carotid intimal-medial wall thickness (CIMT) and coronary artery calcification (CAC). Results were adjusted for age, sex, ethnicity, smoking, systolic blood pressure, LDL cholesterol, HDL cholesterol, antihypertensive medication use, lipid-lowering medication use, and BMI.
Compared with those in the lowest quartile for A1C ([mean ± SD] 5.0 ± 0.2%), participants in the highest quartile (6.0 ± 0.3%) had higher adjusted mean values for common CIMT (0.85 vs. 0.87 mm, P = 0.003) and internal CIMT (1.01 vs. 1.08 mm, P = 0.003). A1C quartile was not associated with prevalence of CAC in the entire cohort (P = 0.27); however, the association was statistically significant in women (adjusted prevalence of CAC in lowest and highest A1C quartiles 37.5 vs. 43.0%, P = 0.01). Among those with some CAC, higher A1C quartile tended to be associated with higher CAC score, but the results were not statistically significant (adjusted P = 0.11).
In this multiethnic cohort, there were small, positive associations between A1C, common CIMT, and internal CIMT in the absence of clinically evident diabetes. An association between higher A1C and CAC prevalence was evident only in women.
PMCID: PMC2732160  PMID: 19549732
8.  How One Division at NHLBI Establishes Its Scientific Priorities 
PMCID: PMC2758646  PMID: 19520248
9.  Prevention of Atrial Fibrillation: Report from an NHLBI Workshop 
Circulation  2009;119(4):606-618.
The National Heart, Lung, and Blood Institute convened an expert panel April 28-29, 2008 to identify gaps and recommend research strategies to prevent atrial fibrillation (AF). The panel reviewed the existing basic scientific, epidemiologic and clinical literature about AF, and identified opportunities to advance AF prevention research. After discussion, the panel proposed the following recommendations: 1) Enhance understanding of the epidemiology of AF in the population by systematically and longitudinally investigating symptomatic and asymptomatic AF in cohort studies; 2) Improve detection of AF by evaluating the ability of existing and emerging methods and technologies to detect AF; 3) Improve noninvasive modalities for identifying key components of cardiovascular remodeling that promote AF, including genetic, fibrotic, autonomic, structural and electrical remodeling markers; 4) Develop additional animal models reflective of the pathophysiology of human AF; 5) Conduct secondary analyses of already-completed clinical trials to enhance knowledge of potentially effective methods to prevent AF and routinely include AF as an outcome in ongoing and future cardiovascular studies; and 6) Conduct clinical studies focused on secondary prevention of AF recurrence, which would inform future primary prevention investigations.
PMCID: PMC2635942  PMID: 19188521
atrial fibrillation; epidemiology; prevention; risk factors; National Institutes of Health (U.S.)
10.  Coronary Artery Calcification Compared with Carotid Intima-Media Thickness in Prediction of Cardiovascular Disease Incidence: The Multi-Ethnic Study of Atherosclerosis (MESA) 
Archives of internal medicine  2008;168(12):1333-1339.
Coronary artery calcium (CAC) and carotid intima-media thickness (IMT) are noninvasive measures of atherosclerosis that consensus panels have recommended as possible additions to risk factor assessment for predicting the probability of cardiovascular disease (CVD) occurrence.
To assess whether maximum carotid IMT or CAC (Agatston Score) is the better predictor of incident CVD.
Design, Setting, Patients
Prospective cohort study of 45–84 year-olds initially free of CVD (n = 6,698) in four ethnic groups, with standardized carotid IMT and CAC measures at baseline, in six field centers of the Multi-Ethnic Study of Atherosclerosis (MESA).
Main Outcome Measure(s)
Incident CVD events (coronary heart disease, stroke, and fatal CVD) over a maximum of 5.3 years of follow-up.
There were 222 CVD events during follow-up. CAC was associated more strongly than carotid IMT with risk of incident CVD. After adjustment for each other and traditional CVD risk factors, the hazard of CVD increased 2.1-fold (95% CI 1.8–2.5) for each standard deviation greater level of log-transformed CAC, versus 1.3-fold (95% CI 1.1–1.4) for each standard deviation greater maximum IMT. For coronary heart disease, the hazard ratios per standard deviation increment were 2.5-fold (95% CI 2.1–3.1) for CAC and 1.2-fold (95% CI 1.0–1.4) for IMT. An ROC analysis also suggested that CAC predicted incident CVD better than IMT did.
Although whether and how to clinically use bio-imaging tests of subclinical atherosclerosis remains a topic of debate, this study found that CAC predicts subsequent CVD events better than does carotid IMT.
PMCID: PMC2555989  PMID: 18574091

Results 1-10 (10)