The Multi-Ethnic Study of Atherosclerosis (MESA) and the Heinz Nixdorf Recall Study (HNR)) differed in regards to informing physicians and patients of the results of their subclinical atherosclerosis.
This study investigates whether the association of coronary artery calcium (CAC) with incident non-fatal and fatal cardiovascular (CVD) events is different among these two large, population-based observational studies.
All Caucasian subjects aged 45–75 years, free of baseline cardiovascular disease were included (n=2232 in MESA, n=3119 HNR participants). We studied the association between CAC and event rates at 5 years, including hard cardiac events (MI, cardiac death, resuscitated cardiac arrest), and separately added revascularizations, and strokes (fatal and non-fatal) to determine adjusted hazard ratios (HR).
Both cohorts demonstrated very low CHD (including revascularization) rates with zero calcium (1.13 and 1.16% over 5 years in MESA and HNR respectively) and increasing significantly in both groups with CAC 100–399 (6.71 and 4.52% in MESA and HNR) and CAC >400 (12.5 and 13.54% in MESA and HNR respectively) and demonstrating strong independent predictive values for scores of 100–399 and >400, despite multivariable adjustment for risk factors. Risk factor adjusted five year revascularization rates were nearly identical for HNR and MESA, and generally low for both studies (1.4% [45/3119] for HNR and 1.9% [43/2232] for MESA) over 5 years.
Across two culturally diverse populations, CAC >400 is a strong predictor of events. High CAC did not determininistically result in revascularization and knowledge of CAC did not increase revascularizations.
coronary artery calcification; subclinical atherosclerosis; Multi-Ethnic Study of Atherosclerosis (MESA); Heinz Nixdorf Recall Study (HNR)
The association between non-steroidal anti-inflammatory drugs (NSAIDs) and the incidence of valvular and arterial calcification is not well established despite known associations between these drugs and cardiovascular events.
To compare the association between the baseline use of aspirin with other NSAID class medications with the incidence and prevalence of aortic valve calcification (AVC) and coronary artery calcium (CAC).
The relationship of NSAID use to AVC and CAC detected by computed tomography was assessed in 6,814 participants within the Multi-Ethnic Study of Atherosclerosis (MESA) using regression modeling. Results were adjusted for age, sex, ethnicity, study site, anti-hypertensive medication use, education, income, health insurance status, diabetes, smoking, exercise, body mass index, blood pressure, serum lipids, inflammatory markers, fasting glucose, statin medication use, and a simple diet score. Medication use was assessed by medication inventory at baseline which includes the use of non-prescription NSAIDs. MESA collects information on both incident and prevalent calcification. The 4,814 participants of the Heinz Nixdorf Recall (HNR) Study, a German prospective cohort study with similar measures of calcification, were included in this analysis to enable replication.
Mean age of the MESA participants was 62 years (51% female). After adjustment for possible confounding factors, a possible association between aspirin use and incident AVC (Relative Risk(RR): 1.60; 95%Confidence Interval (CI): 1.19–2.15) did not replicate in the HNR cohort (RR: 1.06; 95%CI: 0.87–1.28). There was no significant association between aspirin use and incident CAC in the MESA cohort (RR 1.08; 95%CI: 0.91–1.29) or in the HNR cohort (RR 1.24; 95%CI: 0.87–1.77). Non-aspirin NSAID use was not associated with either AVC or CAC in either cohort. There were no associations between regular cardiac dose aspirin and incident calcification in either cohort.
Baseline NSAID use, as assessed by medication inventory, appears to have no protective effect regarding the onset of calcification in either coronary arteries or aortic valves.
Non-steroidal anti-inflammatory drugs; aspirin; aortic valve calcification; coronary artery calcification; Multi-Ethnic Study of Atherosclerosis; Heinz Nixdorf Recall Study
We develop a new diabetes CHD risk estimator using traditional risk factors plus coronary artery calcium (CAC), ankle-brachial index (ABI), high sensitivity C-reactive protein, family history of CHD, and carotid intima-media thickness and compared it with United Kingdom Prospective Diabetes study (UKPDS), Framingham risk and the NCEP/ATP III risk scores in type 2 diabetes mellitus (T2DM).
Methods and Results
We combined data from T2DM without clinical CVD in the Multi-Ethnic Study of Atherosclerosis (MESA) and the Heinz Nixdorf Recall Study (N=1343). After a mean follow-up of 8.5 years, 85(6.3%) participants had incident CHD. Among the novel risk markers, CAC best predicted CHD independent of the FRS [hazard ratio: HR (95% CI): log (CAC +25):1.69(1.45 – 1.97), p<0.0001; CAC categories: CAC ≤ 25 as reference, >25 and ≤ 125:2.29(0.87 – 5.95), >125 and ≤ 400: 3.87(1.57– 9.57), >400: 5.97(2.57– 13.84), respectively). The MESA-HNR diabetes CHD risk score has better accuracy for the main outcome versus the FRS or UKPDS [area under curve (AUC) of 0.76 vs. 0.70 and 0.69, respectively; all p<0.05]. The MESA-HNR risk score improved risk classification versus the FRS (net reclassification improvement (NRI) = 0.19 and integrated discrimination improvement (IDI) =0.046, p<0.05) and UKPDS (NRI=0.215 and IDI = 0.046, p<0.05). Compared with the ATP III guidelines, the MESA-HNR score has an NRI of 0.74 for the main outcome.
This new CHD risk estimator has better discriminative ability for incident CHD than the FRS, UKPDS, and the ATP III/NCEP recommendations in a multi-ethnic cohort with T2DM.
Diabetes mellitus; coronary calcium score; risk assessment; coronary heart disease
On the basis of the Framingham risk algorithm, overestimation of clinical events has been reported in some European populations. Electron-beam computed tomography-derived quantification of coronary artery calcification (CAC) allows for noninvasive assessment of coronary atherosclerosis in the general population and may thus add important in vivo information on the path from risk factor exposure to formation of clinical events. The current study was undertaken to compare the relationship between risk factors and subclinical coronary atherosclerosis between non-Hispanic white cohorts in Germany and US-America, the hypothesis being that subclinical coronary atherosclerosis might be less prevalent in Europe at the same level of classical risk factor exposure.
The Heinz Nixdorf Recall (HNR) study, conducted in the German Ruhr area and the Epidemiology of Coronary Calcification (ECAC) study, conducted in Olmsted County, Minnesota, both recruited large unselected cohorts, men and women aged 45 – 74 years, from the general population. All subjects with no history of coronary artery disease (CAD) or stroke were included (n = 3,120 in HNR, n = 703 in ECAC). Coronary risk factors were assessed by personal and computer-assisted interviews and direct laboratory measurements. Cardiovascular medication use (antihypertensive, lipid-lowering, and anti-diabetic) was noted. CAC scores were determined using the Agatston method in an identical fashion in both studies.
Adverse levels of risk factors were more prevalent, and the Framingham risk score was higher (10.6 ± 7.6 vs. 9.3 ± 7.1, p < 0.001) in HNR than ECAC, respectively. There was no difference in body mass index (BMI). CAC scores were greater in HNR than in ECAC (mean values, 155.7 ± 423.0 versus 107.2 ± 280.0; median values, 11.9 versus 2.4; p < 0.001, respectively). When subjects were matched on CAD risk factors, presence and quantity of CAC were similar in the 2 cohorts. Risk factors significantly associated with CAC score in both studies included: age, male sex, current and former smoking, systolic blood pressure, and non HDL-cholesterol. Inferences were similar after excluding subjects using lipid- or blood pressure-lowering medications. Using the same risk factor variables for modelling, the predicted CAC scores were comparable in both cohorts.
In the higher-risk German cohort, presence and quantity of CAC were greater than in the lower-risk US-American cohort. Risk factor associations, however, with CAC were very similar in both unselected populations. As opposed to studies concerning clinical endpoints, we could not demonstrate a relative increase in subclinical coronary atherosclerosis in the US-American cohort.
The measurement of carotid intima-media thickness (CIMT) is a valid method to quantify levels of atherosclerosis. The present study was conducted to compare the strengths of associations between CIMT and cardiovascular risk factors in two different populations.
The Multi-Ethnic Study of Atherosclerosis (MESA) and the Heinz Nixdorf Recall Study (HNR) are two population-based prospective cohort studies of subclinical cardiovascular disease. All Caucasian subjects aged 45 to 75 years from these cohorts who were free of baseline cardiovascular disease (n = 2,820 in HNR, n = 2,270 in MESA) were combined. CIMT images were obtained using B-mode sonography at the right and left common carotid artery and measured 1 cm starting from the bulb.
In both studies, age, male sex, and systolic blood pressure showed the strongest association (P < .0001 for each) for a higher CIMT. The mean of mean far wall CIMT was slightly higher in MESA participants (0.71 vs 0.67 mm). Almost all significant variables were consistent between the two cohorts in both magnitude of association with CIMT and statistical significance, including age, sex, smoking, diabetes, cholesterol levels, and blood pressure. For example, the association with systolic blood pressure was (ΔSD = 0.011; 95% confidence interval, 0.0009 to 0.014) per mm Hg in MESA and (ΔSD = 0.010; 95% confidence interval, 0.005 to 0.021) per mm Hg in HNR. This consistency persisted throughout the traditional (Framingham) risk factors.
A comparison of the associations between traditional cardiovascular risk factors and CIMT across two culturally diverse populations showed remarkable consistency.
Carotid intima-media thickness; Subclinical atherosclerosis; Multi-Ethnic Study of Atherosclerosis; MESA; Heinz Nixdorf Recall Study; HNR
To determine the association of HIV, immunologic, and inflammatory factors on coronary artery calcium (CAC), a marker of subclinical atherosclerosis.
Cross-sectional study comparing baseline data of males from Hawaii Aging with HIV –Cardiovascular Study (HAHCS) with the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. The cohorts were pooled to determine effects of HIV on CAC and explore immunologic and inflammatory factors that may explain development of CAC in HIV. Multivariable regression models compared CAC prevalence in HAHCS with MESA adjusting for coronary heart disease (CHD) risk profiles.
We studied 100 men from HAHCS and 2733 men from MESA. Positive CAC was seen in 58% HAHCS participants and 57% MESA participants. Mean CAC was 260.8 in HAHCS and 306.5 in MESA. Using relative risk (RR) regression, HAHCS participants had a greater risk (RR=1.20, P<0.05) of having positive CAC than MESA when adjusting for age, smoking status, diabetes, antihypertensive therapy, BMI, systolic blood pressure, total cholesterol, and HDL cholesterol. Among participants with positive CAC, HIV infection was not associated with larger amounts of CAC. Among HAHCS participants, current HIV viral load, CD4, length of HIV, interleukin 6 (IL-6), fibrinogen, C-reactive protein (CRP), and D-dimer were not associated with the presence or amount of CAC.
HIV was independently associated with a positive CAC in men with increased likelihood occurring between 45 and 50 years of age. Current HIV viral load, CD4 count, length of HIV, and inflammatory markers were unrelated to either presence or amount of CAC.
Antiviral therapy; Coronary artery calcium; MESA; Framingham Risk Score
South Asians (individuals from India, Pakistan, Bangladesh, Nepal, and Sri Lanka) have high rates of cardiovascular disease which cannot be explained by traditional risk factors. Few studies have examined coronary artery calcium (CAC) in South Asians.
We created a community-based cohort of South Asians in the United States and compared the prevalence and distribution of CAC to four racial/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA). We compared 803 asymptomatic South Asians free of cardiovascular disease to the four MESA racial/ethnic groups (2,622 Whites, 1,893 African Americans, 1,496 Latinos and 803 Chinese Americans).
The age-adjusted prevalence of any CAC was similar between White and South Asian men, but was lower in South Asian women compared to White women. After adjusting for all covariates associated with CAC, South Asian men were similar to White men and had higher CAC scores compared to African Americans, Latinos and Chinese Americans. In fully adjusted models, CAC scores were similar for South Asian women compared to all women enrolled in MESA. However, South Asian women ≥70 years had a higher prevalence of any CAC than most other racial/ethnic groups.
South Asian men have similarly high CAC burden as White men, but higher CAC than other racial/ethnic groups. South Asian women appear to have similar CAC burden compared to other women, but have somewhat higher CAC burden in older age. The high burden of subclinical coronary atherosclerosis in South Asians may partly explain higher rates of cardiovascular disease in South Asians.
South Asians; ethnic differences; subclinical atherosclerosis; coronary artery calcium
Coronary heart disease (CHD) incidence has declined significantly in the US, as have levels of major coronary risk factors, including LDL-cholesterol, hypertension and smoking, but whether trends in subclinical atherosclerosis mirror these trends is not known.
Methods and Findings
To describe recent secular trends in subclinical atherosclerosis as measured by serial evaluations of coronary artery calcification (CAC) prevalence in a population over 10 years, we measured CAC using computed tomography (CT) and CHD risk factors in five serial cross-sectional samples of men and women from four race/ethnic groups, aged 55–84 and without clinical cardiovascular disease, who were members of Multi-Ethnic Study of Atherosclerosis (MESA) cohort from 2000 to 2012. Sample sizes ranged from 1062 to 4837. After adjusting for age, gender, and CT scanner, the prevalence of CAC increased across exams among African Americans, whose prevalence of CAC was 52.4% in 2000–02, 50.4% in 2003–04, 60.0% is 2005–06, 57.4% in 2007–08, and 61.3% in 2010–12 (p for trend <0.001). The trend was strongest among African Americans aged 55–64 [prevalence ratio for 2010–12 vs. 2000–02, 1.59 (95% confidence interval 1.06, 2.39); p = 0.005 for trend across exams]. There were no consistent trends in any other ethnic group. Risk factors generally improved in the cohort, and adjustment for risk factors did not change trends in CAC prevalence.
There was a significant secular trend towards increased prevalence of CAC over 10 years among African Americans and no change in three other ethnic groups. Trends did not reflect concurrent general improvement in risk factors. The trend towards a higher prevalence of CAC in African Americans suggests that CHD risk in this population is not improving relative to other groups.
To compare the association of the Framingham Risk Score (FRS) and Reynolds Risk Score (RRS) with subclinical atherosclerosis, assessed by incidence and progression of coronary artery calcium (CAC).
The comparative effectiveness of competing risk algorithms for indentifying subclinical atherosclerosis is unknown.
The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective cohort study of 6,814 participants free of baseline CVD. All participants underwent risk factor assessment, as well as baseline and follow-up CAC testing. We assessed the performance of the FRS and RRS to predict CAC incidence and progression using relative risk and robust linear regression.
The study population included 5,140 individuals (61±10 years, 47% males, mean follow-up: 3.1±1.3 years). Among 53% of subjects (n=2,729) with no baseline CAC, 18% (n=510) developed incident CAC. Both the FRS and RRS were significantly predictive of incident CAC [RR 1.40 (95% CI 1.29 – 1.52), and RR 1.41 (95% CI 1.30 – 1.54) per 5% increase in risk, respectively] and CAC progression [mean CAC score change 6.92 (95% CI 5.31 – 8.54) and 6.82 (95% CI 5.51 – 8.14) per 5% increase]. Discordance in risk category classification (< or > 10% 10-year CHD risk) occurred in 13.7%, with only the RRS consistently adding predictive value for incidence and progression of CAC. These subclinical atherosclerosis findings are supported by a CHD events analysis over 5.6±0.7 year follow-up.
Both the RRS and FRS predict onset and progression of subclinical atherosclerosis. However, the RRS may provide additional predictive information when discordance between the scoring systems exists.
coronary artery calcium progression; subclinical atherosclerosis; risk prediction; Reynolds Risk Score; Framingham Risk Score
Obstructive sleep apnea (OSA) is a common condition associated with cardiovascular disease. Its potential effect on progression of subclinical atherosclerosis is not well understood. We tested the hypothesis that self‐reported OSA is associated with progression of coronary artery calcium (CAC). We also evaluated whether traditional cardiovascular risk factors accounted for the association.
Methods and Results
In the Multi‐Ethnic Study of Atherosclerosis (MESA) prospective cohort, we studied 2603 participants who at baseline (2002–2004) completed a sleep questionnaire and underwent coronary computed tomography (CT) and, then 8 years later (2010–2011), a repeat coronary CT. Participants were categorized by symptoms of habitual snoring or reported physician diagnosis of OSA. At baseline, 102 (3.9%) reported diagnosed OSA; 666 (25.6%) reported diagnosed habitual snoring; and 1835 (70.5%) reported neither habitual snoring nor OSA (“normal”). At baseline, CAC prevalence was highest among those with OSA but similar for those with and without habitual snoring. During 8 years of follow‐up, greater progression of CAC was observed among those with OSA versus normal (mean increase of 204.2 versus 135.5 Agatston units; P=0.01), after accounting for demographics, behaviors, and body habitus. Modest attenuation was observed after adjustment for cardiovascular risk factors (188.7 versus 138.8; P=0.06). CAC progression among habitual snorers was similar to that observed in the normal group.
OSA was associated with CAC score progression after adjustment for demographics, behaviors, and body mass index. However, the association was not significant after accounting for cardiovascular risk factors, which may mediate the association between OSA and CAC.
coronary artery calcium; obstructive sleep apnea; snoring; subclinical atherosclerosis risk factor
Elevated coronary artery calcium (CAC) is a marker for increase risk of coronary heart disease (CHD). While the majority of CHD events occur among individuals with advanced CAC, CHD can also occur in individuals with little or no calcified plaque. In this study, we sought to evaluate the characteristics associated with incident CHD events in the setting of minimal (score ≤10) or absent CAC (score of zero).
Asymptomatic participants in the Multi-Ethnic Study of Atherosclerosis (MESA) (N=6,809), were followed for occurrence of all CHD events (including myocardial infarction(MI), angina, resuscitated cardiac arrest, or CHD death) and hard CHD events (MI or CHD death). Time to incident CHD was modeled using age-and gender-adjusted Cox regression.
The final study population consisted of 3,923 MESA asymptomatic participants (mean age: 58±9years,39% males) had with CAC scores of 0-10. Overall no detectable CAC was seen in 3415 individuals, whereas 508 had CAC scores of 1-10. During follow up (median 4.1 years) there were 16 incident hard events, and 28 all CHD events in individuals with absent or minimal CAC. In age, gender, race and CHD risk factors adjusted analysis, minimal CAC (1-10) was associated with an estimated 3-fold greater risk of a hard CHD event (HR: 3.23, 95% CI: 1.17-8.95), or of all CHD event (HR: 3.66, 95% CI 1.71-7.85) compared to those with CAC=0. Former smoking (HR=3.57; 1.08-11.77), current smoking (HR=4.93; 1.20-20.30), and diabetes (HR=3.09; 1.07-8.93) were significant risk factors for events in those with CAC=0.
Asymptomatic persons with absent or minimal CAC are at very low risk of future cardiovascular events. Individuals with minimal CAC (1-10) were significantly increased to three fold increased risk for incident CHD events relative to those with CAC scores of zero.
Computed Tomography; Prognosis; Coronary Artery Calcification; Atherosclerosis; Coronary Calcium Score; Cardiac Events
This study assessed the cross-sectional association between coronary artery calcification (CAC) and myocardial perfusion in an asymptomatic population.
Clinical studies showed that the prevalence of stress-induced ischemia increased with CAC burden among patients with coronary heart disease (CHD). Whether an association between CAC and myocardial perfusion exists in subjects without a history of CHD remains largely unknown.
A total of 222 men and women, ages 45 to 84 years old and free of CHD diagnosis, in the Minnesota field center of the MESA (Multi-Ethnic Study of Atherosclerosis) were studied. Myocardial blood flow (MBF) was measured using magnetic resonance imaging during rest and adenosine-induced hyperemia. Perfusion reserve was calculated as the ratio of hyperemic to resting MBF. Agatston CAC score was determined from chest multidetector computed tomography.
Mean values of hyperemic MBF and perfusion reserve, but not resting MBF, were monotonically lower across increasing CAC levels. After adjusting for age and gender, odds ratios (95% confidence intervals) of reduced perfusion reserve (<2.5) for subjects with CAC scores of 0, 0.1 to 99.9, 100 to 399, and ≥400 were 1.00 (reference), 2.16 (0.96 to 4.84), 2.81 (1.04 to 7.58), and 4.99 (1.73 to 14.4), respectively. Further adjustment for other coronary risk factors did not substantially modify the association. However, the inverse association between perfusion reserve and CAC attenuated with advancing age (p for interaction < 0.05).
Coronary vasodilatory response was associated inversely with the presence and severity of CAC in asymptomatic adults. Myocardial perfusion could be impaired by or manifest the progression to subclinical coronary atherosclerosis in the absence of clinical CHD.
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.
RESEARCH DESIGN AND METHODS
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.
We sought to evaluate the impact of coronary artery calcium (CAC) burden and regional distribution on the need for and type of future coronary revascularization (percutaneous [PCI] vs. surgical [CABG]) among asymptomatic individuals.
The need for coronary revascularization and the chosen mode of revascularization are thought to be a function of disease burden and anatomic distribution. The association between the baseline burden and regional distribution of CAC and the risk and type of future coronary revascularization remains unknown.
6,540 MESA participants (individuals aged 45-84 years, free of known baseline cardiovascular disease) with vessel-specific CAC measurement were followed for median 8.5 (7.7 – 8.6) years. Annualized rates and multivariable adjusted hazard ratios for revascularization and revascularization type were analyzed according to CAC score category, number of vessels with CAC (0-4, including the left main), and by involvement of individual coronary arteries.
A total of 265 revascularizations (4.2%) occurred during follow-up, and 206 (78% of total) were preceded by adjudicated symptoms. Revascularization was uncommon when CAC=0 (0.6%), with graded increase over both rising CAC burden and increasingly diffuse CAC distribution. The revascularization rate per 1,000 person-years for CAC 1-100, 101-400, and >400 was 4.9, 11.7 and 25.4; for 1, 2, 3, and 4 vessels with CAC the rates were 3.0, 8.0, 16.1, and 24.8. In multivariable models adjusting for CAC score, number of vessels with CAC remained predictive of mode of revascularization. Independent predictors of CABG vs. PCI included 3 or 4 vessel CAC, higher CAC burden, and involvement of the left main. Risk for CABG was extremely low with <3 vessel baseline CAC. Results were similar when considering only symptom-driven revascularizations.
In this multi-ethnic cohort of asymptomatic individuals, baseline CAC was highly predictive of future coronary revascularization procedures, with measures of CAC burden and distribution each independently predicting need for PCI vs. CABG over 8.5 year follow-up.
cardiac CT; coronary artery calcium; coronary artery disease; revacularization
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%).
Framingham risk score; coronary calcium; coronary heart disease; number needed to screen; risk factors; population; atherosclerosis; low risk
The ongoing 1000 brains study (1000BRAINS) is an epidemiological and neuroscientific investigation of structural and functional variability in the human brain during aging. The two recruitment sources are the 10-year follow-up cohort of the German Heinz Nixdorf Recall (HNR) Study, and the HNR MultiGeneration Study cohort, which comprises spouses and offspring of HNR subjects. The HNR is a longitudinal epidemiological investigation of cardiovascular risk factors, with a comprehensive collection of clinical, laboratory, socioeconomic, and environmental data from population-based subjects aged 45–75 years on inclusion. HNR subjects underwent detailed assessments in 2000, 2006, and 2011, and completed annual postal questionnaires on health status. 1000BRAINS accesses these HNR data and applies a separate protocol comprising: neuropsychological tests of attention, memory, executive functions and language; examination of motor skills; ratings of personality, life quality, mood and daily activities; analysis of laboratory and genetic data; and state-of-the-art magnetic resonance imaging (MRI, 3 Tesla) of the brain. The latter includes (i) 3D-T1- and 3D-T2-weighted scans for structural analyses and myelin mapping; (ii) three diffusion imaging sequences optimized for diffusion tensor imaging, high-angular resolution diffusion imaging for detailed fiber tracking and for diffusion kurtosis imaging; (iii) resting-state and task-based functional MRI; and (iv) fluid-attenuated inversion recovery and MR angiography for the detection of vascular lesions and the mapping of white matter lesions. The unique design of 1000BRAINS allows: (i) comprehensive investigation of various influences including genetics, environment and health status on variability in brain structure and function during aging; and (ii) identification of the impact of selected influencing factors on specific cognitive subsystems and their anatomical correlates.
cohort; connectivity; Heinz Nixdorf Recall Study; resting-state; imaging genetics; variability; aging; elderly
This study sought to evaluate the relationship between microalbuminuria (MA) and the development and progression of atherosclerosis, as assessed by incident and progression of coronary artery calcification (CAC).
MA is associated with an increased risk of cardiovascular disease, but the mechanism by which MA imparts this increased risk is not known.
The MESA (Multi-Ethnic Study of Atherosclerosis) study is a prospective cohort study of 6,814 self-identified White, African-American, Hispanic, or Chinese participants free of clinical cardiovascular disease at entry. Of the 6,775 individuals with available urine albumin data, we excluded 97 subjects with macroalbuminuria and 1,023 with missing follow-up CAC data. The final study population consists of 5,666 subjects.
At baseline, individuals with MA were more likely to have CAC >0 compared with those without MA (62% vs. 48%, p < 0.0001). During a mean follow-up of 2.4 ± 0.8 years, those with MA and no CAC at baseline were more likely to develop CAC (relative risk [RR]: 2.05, 95% confidence interval [CI]: 1.41 to 3.02, p < 0.0001) as compared with those without MA in demographic-adjusted analyses. After multivariant adjustment, the relationship was attenuated but remained statistically significant (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005). Among those with CAC at baseline, those with versus those without MA had a 15 (95% CI: 8 to 22, p < 0.0001) volume units higher median increase in CAC in demographic-adjusted analyses. After multivariant adjustment, MA remained associated with incident CAC (RR: 1.76, 95% CI: 1.19 to 2.61, p = 0.005) and with progression of CAC (median increase in CAC volume score of 9 [95% CI: 2 to 16, p = 0.009]), relative to those without MA.
This large multiethnic, population-based study of asymptomatic individuals demonstrates an increased risk of incident CAC as well as greater CAC progression among those with MA. Further study is needed to determine the degree to which MA precedes and predicts progression of atherosclerosis and how this information can be used to reduce cardiovascular events.
coronary artery calcium; microalbuminuria; risk prediction; coronary heart disease; Multi-Ethnic Study of Atherosclerosis
We hypothesized that individuals with low 10-year but high lifetime cardiovascular disease (CVD) risk would have a greater burden of subclinical atherosclerosis than those with low 10-year but low lifetime risk.
Methods and Results
We included 2988 individuals age ≤50 at exam year 15 from the Coronary Artery Risk Development in Young Adults (CARDIA) study and 1076 individuals age ≤50 at study entry from the Multi-Ethnic Study of Atherosclerosis (MESA). The 10-year risk and lifetime risk for CVD were estimated for each participant, permitting stratification into three groups: low 10-year (<10%)/low lifetime (<39%) risk, low 10-year (<10%)/high lifetime risk (≥39%), and high 10-year risk (≥10%) or diagnosed diabetes. Baseline levels and change in levels of subclinical atherosclerosis (coronary artery calcium [CAC] or carotid intima-media thickness [IMT]) were compared across risk strata. Among participants with low 10-year risk (91% of all participants) in CARDIA, those with a high lifetime risk compared to low lifetime risk had significantly greater common (0.83 vs 0.80 mm in men; 0.79 vs 0.75 mm in women) and internal (0.85 vs 0.80 mm; 0.80 vs 0.76 mm) carotid IMT, higher CAC prevalence (16.6 vs 9.8%; 7.1 vs 2.3%), and significantly greater incidence of CAC progression (22.3 vs 15.4%; 8.7 vs 5.3%). Similar results were observed in MESA.
Individuals with low 10-year but high lifetime risk have a greater subclinical disease burden and greater incidence of atherosclerotic progression compared to individuals with low 10-year and low lifetime risk, even at younger ages.
epidemiology; risk estimation; prevention
We assessed the predictive value of coronary artery calcium (CAC) score for CVA events in an asymptomatic multi-ethnic cohort.
The coronary artery calcium (CAC) score, a measure of atherosclerotic burden, has been shown to improve prediction of coronary heart disease events. However, the predictive value of CAC for cerebrovascular (CVA) events is unclear.
CAC was measured at baseline exam of participants (N=6779) of the Multi Ethnic Study of atherosclerosis (MESA) and then followed for an average of 9.5(2.4) years for the diagnosis of incident CVA defined as all strokes or TIAs.
During the follow up 234(3.5%) adjudicated CVA events occurred. In Kaplan Meier analysis the presence of CAC was associated with a lower CVA event - free survival versus CAC absent (Log rank χ2 = 59.8, p<0.0001). Log transformed CAC was associated with increased risk for CVA after adjusting for age, gender, race/ethnicity, BMI, systolic and diastolic blood pressure, total cholesterol, HDL-C, cigarette smoking status, blood pressure medication use, statin use and interim atrial fibrillation[hazard ratio(95% CI): 1.13(1.07 – 1.20),p<0.0001]. The ACC/AHA recommended CAC cut off was also an independent predictor of CVA and strokes [HR (95%CI): 1.70(1.24–2.35),p=0.001 and 1.59(1.11–2.27), p=0.01 respectively]. CAC was an independent predictor of CVA when analysis was stratified by gender or race/ethnicity, and improved discrimination for CVA when added to the full model (c statistic: 0.744 vs. 0.755). CAC also improved the discriminative ability of the Framingham stroke risk score for CVA.
CAC is an independent predictor of CVA events, and improves the discrimination afforded by current stroke risk factors or the Framingham stroke risk score for incident CVA in an initially asymptomatic multi-ethnic adult cohort.
Coronary artery calcium score; cerebrovascular disease; risk prediction; prevention
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.
The MESA (Multi-Ethnic Study of Atherosclerosis) is an ongoing study of the prevalence, risk factors, and progression of subclinical cardiovascular disease in a multi-ethnic cohort. It provides a valuable opportunity to examine the development and progression of CAC (coronary artery calcium), which is an important risk factor for the development of coronary heart disease. In MESA, about half of the CAC scores are zero and the rest are continuously distributed. Such data has been referred to as “zero-inflated data” and may be described using two-part models. Existing two-part model studies have limitations in that they usually consider parametric models only, make the assumption of known forms of the covariate effects, and focus only on the estimation property of the models. In this article, we investigate statistical modeling of CAC in MESA. Building on existing studies, we focus on two-part models. We investigate both parametric and semiparametric, and both proportional and nonproportional models. For various models, we study their estimation as well as prediction properties. We show that, to fully describe the relationship between covariates and CAC development, the semiparametric model with nonproportional covariate effects is needed. In contrast, for the purpose of prediction, the parametric model with proportional covariate effects is sufficient. This study provides a statistical basis for describing the behaviors of CAC and insights into its biological mechanisms.
Both coronary artery calcification (CAC) and the ankle brachial index (ABI) are measures of subclinical atherosclerotic disease. The influence of physical activity on the longitudinal change in these measures remains unclear. To assess this we examined the association between these measures and self-reported physical activity in the Multi-Ethnic Study of Atherosclerosis (MESA).
At baseline, the MESA participants were free of clinically evident cardiovascular disease. We included all participants with an ABI between 0.90 and 1.40 (n=5656). Predictor variables were based on self-reported measures with physical activity being assessed using the Typical Week Physical Activity Survey from which metabolic equivalent-minutes/week of activity were calculated. We focused on physical activity intensity, intentional exercise, sedentary behavior, and conditioning. Incident peripheral artery disease (PAD) was defined as the progression of ABI to values below 0.90 (given the baseline range of 0.90 to 1.40). Incident CAC was defined as a CAC score >0 Agatston units upon follow up with a baseline score of 0 Agatston units.
Mean age was 61 years, 53% were female, and mean body mass index was 28 kg/m2. After adjusting for traditional cardiovascular risk factors and socioeconomic factors, intentional exercise was protective for incident peripheral artery disease (Relative Risk (RR)= 0.85, 95% Confidence Interval (CI): 0.74 to 0.98). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, there was a significant association between vigorous PA and incident CAC (RR=0.97, 95% CI: 0.94 to 1.00). There was also a significant association between sedentary behavior and increased amount of CAC among participants with CAC at baseline (Δlog(Agatston Units +25)=0.027, 95% CI 0.002, 0.052).
These data suggest that there is an association between physical activity/sedentary behavior and the progression of two different measures of subclinical atherosclerotic disease.
Ankle Brachial Index; Coronary Artery Calcification; Physical Activity; Epidemiology; Prospective Cohort Study
Examine whether the coronary artery calcium score (CAC) can be used to define the target population to treat with a polypill.
Prior studies suggested a single polypill to reduce cardiovascular disease (CVD) at the population level.
Participants from the Multi-Ethnic Study of Atherosclerosis (MESA) were stratified using the criteria of four polypill studies (TIPS, Poly-Iran, Wald's, and the PILL collaboration). We compared coronary heart disease (CHD) and CVD event rates and calculated 5-year number needed to treat (NNT) after stratification based on the CAC score.
Among MESA participants eligible for the TIPS, Poly-Iran, Wald's and PILL collaboration, a CAC=0 was observed in 58.6%, 54.5%, 38.9% and 40.8%, respectively. The rate of CHD events among those with CAC=0 varied from 1.2 to 1.9 events per 1000 person-years, those with CAC 1- 100 had event rates ranging from 4.1 to 5.5, and in those with CAC>100 the event rate ranged from 11.6 to 13.3. The estimated 5-year NNT to prevent one CVD event ranged from 81 to 130 for individuals with CAC=0, 38 to 54 for those with CAC 1-100, and 18 to 20 for those with CAC>100.
Among individuals eligible for treatment with the polypill, the majority of events occurred in those with CAC>100. The group with CAC=0 had a very low event rate and a high projected NNT. The avoidance of treatment in individuals with CAC=0 could allow for significant reductions in the population considered for treatment, with a more selective use of the polypill and as a result, avoiding treatment in those who are unlikely to be benefit
subclinical atherosclerosis; risk stratification; polypill
Inflammatory markers predict coronary heart disease (CHD). However, associations with coronary artery calcium (CAC), a marker of subclinical CHD, are not established.
We examined cross-sectional associations of C-reactive protein (CRP), interleukin-6 (IL-6) and fibrinogen with CAC presence (Agatston score > 0 by computed tomography) in 6,783 Multi-Ethnic Study of Atherosclerosis (MESA) participants.
In all participants, those in the highest, compared to lowest, quartile of CRP had a relative risk (RR, 95% confidence interval) of 1.13 (1.06-1.19; p<0.01) for CAC in age, sex and ethnicity adjusted models. For highest versus lowest quartiles, relative risks were 1.22 (1.15-1.30; p<0.01) for IL-6 and 1.18 (1.11-1.24; p<0.01) for fibrinogen. Adjusting for CHD risk factors (smoking, diabetes, blood pressure, obesity and dyslipidemia) attenuated RRs. RRs for CAC were 1.05 (0.99-1.12; p=0.63) for CRP, 1.12 (1.06-1.20; p<0.01) for IL-6 and 1.09 (1.02-1.16; p=0.01) for fibrinogen in multivariable adjusted models. Results were similar for men and women and across ethnic groups.
Inflammatory markers were weakly associated with CAC presence and burden in MESA. Our data support the hypothesis that inflammatory biomarkers and CAC reflect distinct pathophysiology.
Atherosclerosis; Calcium; Inflammation; Population
Coronary artery calcium (CAC), measured by computed tomography (CT), has strong predictive value for incident cardiovascular disease (CVD) events. The standard CAC score is the Agatston, which is weighted upward for greater calcium density. However, some data suggest increased plaque calcium density may be protective for CVD.
To determine the independent associations of CAC volume and CAC density with incident CVD events.
Design, Setting, and Participants
Multicenter, prospective observational MESA study (Multi-Ethnic Study of Atherosclerosis), conducted at 6 US field centers of 3398 men and women from 4 race/ethnicity groups; non-Hispanic white, African American, Hispanic, and Chinese. Participants were aged 45-84 years, free of known CVD at baseline, had CAC greater than 0 on their baseline CT, and were followed up through October 2010.
Main Outcomes and Measures
Incident coronary heart disease (CHD) and all CVD events
During a median of 7.6 years of follow-up, there were 175 CHD events and an additional 90 other CVD events for a total of 265 CVD events. With both lnCAC volume and CAC density scores in the same multivariable model, the lnCAC volume score showed an independent association with incident CHD, with a hazard ratio (HR) of 1.81 (95% CI, 1.47-2.23) per standard deviation (SD = 1.6) increase, absolute risk increase 6.1 per 1000 person-years, and for CVD an HR of 1.68 (95% CI, 1.42-1.98) per SD increase, absolute risk increase 7.9 per 1000 person-years. Conversely, the CAC density score showed an independent inverse association, with an HR of 0.73 (95% CI, 0.58-0.91) per SD (SD = 0.7) increase for CHD, absolute risk decrease 5.5 per 1000 person-years, and an HR of 0.71 (95% CI, 0.60-0.85) per SD increase for CVD, absolute risk decrease 8.2 per 1000 person years. Area under the receiver operating characteristic curve analyses showed significantly improved risk prediction with the addition of the density score to a model containing the volume score for both CHD and CVD. In the intermediate CVD risk group, the area under the curve for CVD increased from 0.53 (95% CI, 0.48-0.59) to 0.59 (95% CI, 0.54-0.64), P = .02.
Conclusions and Relevance
CAC volume was positively and independently associated with CHD and CVD risk. At any level of CAC volume, CAC density was inversely and significantly associated with CHD and CVD risk. The role of CAC density should be considered when evaluating current CAC scoring systems.