Atherosclerosis Risk In Communities Participants Research Articles

European ancestry as a risk factor for atrial fibrillation in African Americans.

Despite a higher burden of standard atrial fibrillation (AF) risk factors, African Americans have a lower risk of AF than whites. It is unknown whether the higher risk is due to genetic or environmental factors. Because African Americans have varying degrees of European ancestry, we sought to test the hypothesis that European ancestry is an independent risk factor for AF. We studied whites (n=4543) and African Americans (n=822) in the Cardiovascular Health Study (CHS) and whites (n=10 902) and African Americans (n=3517) in the Atherosclerosis Risk in Communities (ARIC) Study (n=3517). Percent European ancestry in African Americans was estimated with 1747 ancestry informative markers from the Illumina custom ITMAT-Broad-CARe array. Among African Americans without baseline AF, 120 of 804 CHS participants and 181 of 3517 ARIC participants developed incident AF. A meta-analysis from the 2 studies revealed that every 10% increase in European ancestry increased the risk of AF by 13% (hazard ratio, 1.13; 95% confidence interval, 1.03 to 1.23; P=0.007). After adjustment for potential confounders, European ancestry remained a predictor of incident AF in each cohort alone, with a combined estimated hazard ratio for each 10% increase in European ancestry of 1.17 (95% confidence interval, 1.07 to 1.29; P=0.001). A second analysis using 3192 ancestry informative markers from a genome-wide Affymetrix 6.0 array in ARIC African Americans yielded similar results. European ancestry predicted risk of incident AF. Our study suggests that investigating genetic variants contributing to differential AF risk in individuals of African versus European ancestry will be informative.

Vital Exhaustion as a Risk Factor for Adverse Cardiac Events (from the Atherosclerosis Risk in Communities [ARIC] Study)

Conclusion: In both men and women, vital exhaustion independently predicts long-term risk for adverse cardiac events. Summary: Vital exhaustion is defined as a state of excessive fatigue, increased irritability, and demoralization. European studies have suggested a link between vital exhaustion and coronary heart disease. The authors attempted to use data from the Atherosclerosis Risk In Communities (ARIC) study to provide United States data on the role of vital exhaustion and acute coronary syndromes. The goal was to determine whether individuals with low exhaustion compared with those with high vital exhaustion were at increased risk for myocardial infarction and fatal coronary heart disease. ARIC participants were black or white men and women aged 48 to 67 years. ARIC is a large population-based prospective study of the cause and natural history of atherosclerosis. Patients are derived from Washington County, Maryland; suburban Minneapolis; Forsyth County, North Carolina; and Jackson, Mississippi. Patients were initially enrolled between 1987 and 1989 and have returned at approximately 3-year intervals for three follow-up clinical examinations. Hospitalizations and death during follow-up are identified through annual telephone interviews and hospital surveillance. In this study, 12,895 participants in ARIC were monitored for occurrence of cardiac morbidity and mortality from 1990 to 2002 (maximum follow-up, 13.0 years). Assessment of vital exhaustion was with the 21-item Maastricht Questionnaire. Scores were divided in quartiles for statistical analysis. Those scoring in the fourth quartile were considered to have high vital exhaustion. High vital exhaustion predicted adverse cardiac events in age-, gender-, and race-adjusted analyses (1.69, 95% confidence interval [CI], 1.40-2.05). High vital exhaustion also predicted adverse cardiac events when adjusted for educational level, body mass index, plasma low-density lipoprotein and high-density lipoprotein cholesterol levels, systolic and diastolic blood pressure, diabetes mellitus, smoking, and past years of smoking (1.46, 95% CI, 1.20-1.79). Risks for adverse cardiac events increased from the first to the fourth quartile of vital exhaustion, and probabilities of adverse cardiac events were higher over time in patients with high vital exhaustion compared with those with low exhaustion levels (P = .002). Vitally exhausted participants in this study, compared with nonexhausted peers, were more likely to be women, black, and have less formal education. Comment: Vital exhaustion is closely linked to depression, and the two conditions share common characteristics such as irritability and fatigue. Fatigue does appear to be a real and measurable risk factor for cardiovascular disease. Clearly, fatigue is associated with myocardial infarction. This is especially so in women: >70% of women in a recent study reported unusual fatigue before myocardial infarction, with about 30% of men reporting fatigue preceding myocardial infarction (McSweeney JC, et al, Circulation 2003;108:2619- 23). Other studies have also suggested an inverse relationship between exhaustion and social and economic status (Schuitemaker GE, et al, Psychosomatics 2004;45:414-8). The Maastricht Questionnaire examines only the presence or absence of vital exhaustion but not the etiology. It is possible that residual or unmeasured confounders, such as the underlying etiology of vital exhaustion, may be additive risk factors for cardiovascular events.

MRI measurements of carotid plaque in the atherosclerosis risk in communities (ARIC) study: Methods, reliability and descriptive statistics

To measure carotid plaque components using MRI and estimate reliability in the population-based Atherosclerosis Risk in Communities (ARIC) study. Contrast-enhanced high-resolution (0.51 x 0.58 x 2 mm(3)) MRI images were acquired through internal (ICA) and common carotid arteries (CCA) of 2066 ARIC participants at four sites. Sixty-one exams were repeated and 164 pairs had repeated interpretations. Plaque component thicknesses, areas and volumes over eight slices (1.6-cm segment) were measured. Intraplaque hemorrhage was recorded. Reliability was evaluated by intraclass correlations and kappa statistics. There were 1769 successful MRI exams (mean age 71 years; 57% females; 81% white; 19% African-Americans). Repeat scan reliability was highest for CCA lumen area (0.94) and maximum wall thickness (0.89), ICA lumen area (0.89) and maximum wall thickness (0.77) and total wall volume (0.79), and lowest for small structures-core volume (0.30) and mean cap thickness (0.38). Overall reliability was primarily related to reader variability rather than scan acquisition. K's for presence of core, calcification and hemorrhage were fair to good. White men had the thickest plaques (average maximum ICA wall thickness = 2.3 mm) and the most cores (34%). The most important limiting factor for MRI measurements of plaque components is reader variability. Measurement error depends largely on the analyzed structure's size.

Clinical Implications of JUPITER (Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin) in a U.S. Population: Insights From the ARIC (Atherosclerosis Risk in Communities) Study

The purpose of this study is to describe the proportion of “JUPITER-eligible” (Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin) individuals and clinical outcomes of individuals based on high-sensitivity C-reactive protein (hs-CRP) and low-density lipoprotein cholesterol (LDL-C) strata in the ARIC (Atherosclerosis Risk in Communities) study. Questions remain after the JUPITER study, including whether the observed cardiovascular disease (CVD) event rates would persist with time and how these event rates would compare with other populations (lower hs-CRP and/or higher LDL-C levels). After stratification into 4 groups based on LDL-C and hs-CRP levels, with cutoffs at 130 mg/dl and 2.0 mg/l, respectively, incident CVD events were examined (mean follow-up, 6.9 years) and compared. Of 8,907 age-eligible participants, 18.2% (n = 1,621) were JUPITER-eligible (hs-CRP ≥2.0 mg/l, LDL-C <130 mg/dl) and had an absolute CVD risk of ∼10.9% over a mean follow-up of 6.9 years (1.57% per year). If JUPITER hazard ratios were applied to this group, the number needed to treat to prevent 1 CVD event would be estimated at 38 over 5 years and 26 over 6.9 years. ARIC participants with elevated hs-CRP and low LDL-C had a CVD event rate of 1.57% per year over 6.9 years, similar to the CVD event rate noted in the JUPITER study placebo group (1.36% per year over 1.9 years). The association of hs-CRP ≥2.0 mg/l with increased CVD risk and mortality regardless of LDL-C provides us a simple method of using age and hs-CRP level for identifying higher risk individuals. (Atherosclerosis Risk in Communities study; NCT00005131 )

Variation in the checkpoint kinase 2 gene is associated with type 2 diabetes in multiple populations

Identification and characterization of the genetic variants underlying type 2 diabetes susceptibility can provide important understanding of the etiology and pathogenesis of type 2 diabetes. We previously identified strong evidence of linkage for type 2 diabetes on chromosome 22 among 3,383 Hypertension Genetic Epidemiology Network (HyperGEN) participants from 1,124 families. The checkpoint 2 (CHEK2) gene, an important mediator of cellular responses to DNA damage, is located 0.22Mb from this linkage peak. In this study, we tested the hypothesis that the CHEK2 gene contains one or more polymorphic variants that are associated with type 2 diabetes in HyperGEN individuals. In addition, we replicated our findings in two other Family Blood Pressure Program (FBPP) populations and in the population-based Atherosclerosis Risk in Communities (ARIC) study. We genotyped 1,584 African-American and 1,531 white HyperGEN participants, 1,843 African-American and 1,569 white GENOA participants, 871 African-American and 1,009 white GenNet participants, and 4,266 African-American and 11,478 white ARIC participants for four single nucleotide polymorphisms (SNPs) in CHEK2. Using additive models, we evaluated the association of CHEK2 SNPs with type 2 diabetes in participants within each study population stratified by race, and in a meta-analysis, adjusting for age, age(2), sex, sex-by-age interaction, study center, and relatedness. One CHEK2 variant, rs4035540, was associated with an increased risk of type 2 diabetes in HyperGEN participants, two replication samples, and in the meta-analysis. These results may suggest a new pathway in the pathogenesis of type 2 diabetes that involves pancreatic beta-cell damage and apoptosis.

Longitudinal impact of physical activity on lipid profiles in middle-aged adults: the Atherosclerosis Risk in Communities Study

Evidence exists that increased levels of physical activity decrease the population burden of cardiovascular disease (CVD). Although risk factors for CVD, including plasma lipids and lipoproteins, have been associated with physical activity, studies including a sizeable number of minority participants are lacking. Our purpose was to interrogate the longitudinal effect of physical activity on plasma lipids and lipoproteins in the African American and white participants of the Atherosclerosis Risk in Communities (ARIC) Study. Nine years of follow-up data on 8,764 individuals aged 45-64 years at baseline were used in linear mixed-effects models to estimate the association between increases in baseline physical activity on mean change in HDL, LDL, total cholesterol, and triglyceride levels. Increases in the level of activity were associated with increases in HDL in all strata and decreases in triglycerides among white participants. Physical activity was associated with LDL in all women, while the association with total cholesterol was limited to African American women. This study is one of the few to investigate the effect of physical activity on lipids and lipoproteins in a race- and sex-specific manner. Overall our results highlight the importance of physical activity on plasma lipid profiles and provide evidence for novel differential associations.

Associations of serum uric acid with cardiovascular events and mortality in moderate chronic kidney disease.

It is unclear whether the presence of kidney disease modifies the associations of uric acid with cardiovascular events and death. In the limited access, public use Atherosclerosis Risk In Communities (ARIC) database, associations of serum uric acid levels with cardiovascular events and death were analysed using a parametric proportional hazards model and the modification of these associations by the presence of CKD was assessed using a likelihood ratio test. Of the 15 366 ARIC participants included in this analysis, 461 had CKD (eGFR <60 ml/min/1.73 m(2)). In both non-CKD and CKD sub-groups, participants with hyperuricaemia (> or = 7 mg/dl in men and > or = 6 mg/dl in women) compared to those with normal serum uric acid levels had higher waist circumference and fasting serum insulin levels. In the entire cohort, in a multivariate parametric proportional hazards model, each mg/dl increase in serum uric acid was associated with an increased hazard of cardiovascular events (HR 1.09, 95% CI 1.05-1.12) and death. A multiplicative interaction term of serum uric acid and CKD when added to the above models was significant (P < 0.001). The likelihood ratio test of the models with and without the interaction term was also significant (P < 0.001). In the non-CKD population, a multivariate analysis after adjusting for comorbidities and metabolic syndrome showed a significant association between hyperuricaemia and mortality (HR 1.18, 95% CI 1.04-1.33) but not for cardiovascular events (HR 1.07, 95% CI 0.96-1.19). In the CKD population, the association was not significant for both mortality and cardiovascular events. We conclude that hyperuricaemia is associated with insulin resistance and mortality in the non-CKD population. The presence of CKD attenuates the associations of uric acid with mortality. Interventional studies are warranted to establish the biological role of hyperuricaemia in mortality in non-CKD and CKD populations.

134 POSTER The rational design of inhibitors of the telomere-hnRNP A1 interaction

Obesity is a leading public health concern, and although environmental factors have been hypothesized to play a role in the prevention of obesity, little empirical data exist to document their effects. The purpose of this study was to examine whether characteristics of the local food environment are associated with the prevalence of cardiovascular disease risk factors.A cross-sectional study of men and women participating in the third visit (1993–1995) of the Atherosclerosis Risk in Communities (ARIC) Study was conducted in 2004. The analyses included 10,763 ARIC participants residing in one of the 207 eligible census tracts located in the four ARIC-defined geographic areas. Names and addresses of food stores located in Mississippi, North Carolina, Maryland, and Minnesota were obtained from departments of agriculture. Multilevel modeling was used to calculate prevalence ratios of the associations between the presence of specific types of food stores and cardiovascular disease risk factors.The presence of supermarkets was associated with a lower prevalence of obesity and overweight (obesity prevalence ratio [PR]=0.83, 95% confidence interval [CI]=0.75–0.92; overweight PR=0.94, 95% CI=0.90–0.98), and the presence of convenience stores was associated with a higher prevalence of obesity and overweight (obesity PR=1.16, 95% CI=1.05–1.27; overweight PR=1.06, 95% CI=1.02–1.10). Associations for diabetes, high serum cholesterol, and hypertension were not consistently observed.Results from this study suggest that characteristics of local food environments may play a role in the prevention of overweight and obesity.

β2-adrenergic receptor polymorphism and venous thromboembolism

Dear Editor: Zee et al recently reported a nested case-control study of 92 gene polymorphisms in relation to venous thromboembolism (VTE) incidence (1). They discovered a statistically significant association of idiopathic, but not total, VTE with the Q27E β2-adrenergic receptor (β2-AR) polymorphism (gln27glu substitution). Odds ratios for genotypes containing the variant allele were modest, ranging from 1.4–1.8 depending on the model (additive, dominant, or recessive). In contrast, Nossent et al found no association between the Q27E polymorphism and VTE in the Leiden Thrombophilia Study (2), and O’Donnell et al found no association in a small case-control study (3). Because we had measured this Q27E polymorphism in the large Atherosclerosis Risk in Communities (ARIC) Study cohort (4), we sought to replicate the finding by Zee et al. We also examined another β2-AR polymorphism (gly16arg) that Zee et al, Nossent et al, and O’Donnell et al found unassociated with VTE (1–3). The ARIC cohort was recruited in 1987–89 from four US communities, underwent epidemiologic examinations, and was followed for cardiovascular events (4). Among 14,210 ARIC participants at risk, 278 VTEs (n = 111 idiopathic) were verified between 1987 and 2002. Like Zee et al, we found no association of the gly16arg polymorphism with VTE. We also found a modest positive but statistically nonsignificant association between the Q27E polymorphism and both total and idiopathic VTE occurrence in ARIC (Table). TABLE Hazard Ratio (HR) for β2-AR Q27E (gln27glu) Polymorphism and Venous Thromboembolism (VTE) in ARIC Further adjustment for body mass index and diabetes, two other risk factors for VTE in ARIC, did not change this finding. In conclusion, the Q27E β2-AR polymorphism was not related to VTE in ARIC, unlike the study by Zee at al (1). It is possible that there is a modest association that we had insufficient power to detect, so a meta-analysis of existing studies could be helpful. Sincerely,

Do Insomnia Complaints Cause Hypertension or Cardiovascular Disease?

We prospectively investigated odds ratios (ORs) for development of hypertension or cardiovascular disease by endorsement of sleep complaints. The Atherosclerosis Risk in Communities (ARIC) Study is a prospective, population-based study of cardiovascular disease. Our study sample was 8757 ARIC participants without hypertension and 11,863 ARIC participants without cardiovascular disease at baseline. We applied multivariate regression analysis to predict the ORs of development of hypertension or cardiovascular disease over 6 years of follow-up by endorsement of symptoms of difficulty falling asleep (DFA), waking up repeatedly (SCD), awakening tired and fatigued (NRS), or combinations of these symptoms. We controlled for age, sex, alcohol intake, income, smoking, diabetes, heart disease, menopausal status, depression, educational level, Body Mass Index, respiratory symptoms, and pulmonary function. Endorsement of all 3 sleep complaints predicted a slightly increased risk of cardiovascular disease (OR 1.5, 1.1-2.0) but not of hypertension. Endorsement of either DFA or SCA predicted slightly increased risk of hypertension (OR 1.2, 1.03-1.3) The definition of insomnia affects its impact. A combination of 3 sleep complaints (DFA, SCD, NRS) predicted a slightly increased risk of cardiovascular disease but not hypertension, and a complaint of either DFA or SCD predicted increased hypertensive risk. It is not clear whether these modest and inconsistent effects are of clinical significance.

Supermarkets, Other Food Stores, and Obesity: The Atherosclerosis Risk in Communities Study

Obesity is a leading public health concern, and although environmental factors have been hypothesized to play a role in the prevention of obesity, little empirical data exist to document their effects. The purpose of this study was to examine whether characteristics of the local food environment are associated with the prevalence of cardiovascular disease risk factors. A cross-sectional study of men and women participating in the third visit (1993-1995) of the Atherosclerosis Risk in Communities (ARIC) Study was conducted in 2004. The analyses included 10,763 ARIC participants residing in one of the 207 eligible census tracts located in the four ARIC-defined geographic areas. Names and addresses of food stores located in Mississippi, North Carolina, Maryland, and Minnesota were obtained from departments of agriculture. Multilevel modeling was used to calculate prevalence ratios of the associations between the presence of specific types of food stores and cardiovascular disease risk factors. The presence of supermarkets was associated with a lower prevalence of obesity and overweight (obesity prevalence ratio [PR] = 0.83, 95% confidence interval [CI] = 0.75-0.92; overweight PR = 0.94, 95% CI = 0.90-0.98), and the presence of convenience stores was associated with a higher prevalence of obesity and overweight (obesity PR = 1.16, 95% CI = 1.05-1.27; overweight PR = 1.06, 95% CI = 1.02-1.10). Associations for diabetes, high serum cholesterol, and hypertension were not consistently observed. Results from this study suggest that characteristics of local food environments may play a role in the prevention of overweight and obesity.

Serum uric acid and risk of ischemic stroke: The ARIC Study

Aims Since serum uric acid (UA) is strongly associated with cardiovascular risk factors, it has been debated whether serum UA is a stroke risk factor or whether UA may be simply “marking” subjects with other, causal risk factors. We therefore investigated the relation between UA and ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) Study. Methods and results Of 15,792 ARIC participants, 13,413 who were free of recognized stroke or coronary heart disease (CHD) at baseline and had a baseline UA measurement were included in the analysis. We followed the participants for ischemic stroke incidence ( N = 381) over 12.6 years. Although serum UA was independently and positively related to ischemic stroke incidence when we adjusted for age, sex, race, and education, the positive relation was weakened when additionally adjusted for possible confounding variables. The positive multivariate-adjusted association between serum UA and ischemic stroke was observed among subjects not using diuretics (adjusted relative hazard in the highest quartile versus the lowest: relative hazard (RH) = 1.49; 95% confidence interval (CI): 1.00–2.23) ( P for trend: 0.02), but not among diuretic users ( P for interaction: 0.08). Conclusion Our findings suggest that UA is an independent predictor of ischemic stroke among subjects not using diuretics, but that elevated UA itself may not cause ischemic stroke.

Traditional and Nontraditional Risk Factors Predict Coronary Heart Disease in Chronic Kidney Disease

Some risk factors for coronary heart disease (CHD) incidence in the general population are not associated with CHD incidence among patients with ESRD but have not been well characterized in chronic kidney disease (CKD). The association of several risk factors with CHD incidence was studied among participants with CKD in the population-based Atherosclerosis Risk in Communities (ARIC) Study. CHD risk factors and estimated GFR using serum creatinine were measured among 807 ARIC participants with CKD (estimated GFR between 15 and 59 ml/min per 1.73 m(2)). The incidence of CHD during 10.5 yr of follow-up was 6.3, 8.5, and 14.4 per 1000 person-years among ARIC participants with an estimated GFR of >/=90, 60 to 89, and 15 to 59 ml/min per 1.73 m(2), respectively. After adjustment for age, race, gender, and ARIC field center, among those with CKD, the relative risk (95% confidence interval) of CHD was 1.65 (1.01 to 2.67) for current smoking, 2.02 (1.27 to 3.22) for hypertension, 3.06 (2.01 to 4.67) for diabetes, and 1.96 (1.14 to 3.36) for anemia. The comparably adjusted relative risks of CHD for each standard deviation higher total and HDL cholesterol were 1.50 (1.25 to 1.71) and 0.79 (0.62 to 1.01), respectively, and 1.38 (1.13 to 1.69), 1.24 (1.06 to 1.46), 0.65 (0.54 to 0.79), and 1.38 (1.19 to 1.59) for waist circumference, leukocyte count, serum albumin, and fibrinogen, respectively. CHD risk factors in the general population remain predictive among patients with CKD. Given the high risk for CHD among patients with CKD, control of these risk factors may have a substantial impact on their excess burden of CHD.

Interaction between soluble thrombomodulin and intercellular adhesion molecule-1 in predicting risk of coronary heart disease.

Results from previous ARIC (Atherosclerosis Risk In Communities) analyses indicate that soluble intercellular adhesive molecule-1 (sICAM) and soluble thrombomodulin (sTM) levels are associated with risk of coronary heart disease (CHD) in an opposite direction. A high sICAM level increases the risk of CHD, whereas a high level of sTM has a lower risk of CHD. It was unclear whether there was an interaction between sTM and sICAM. Using a nested case-cohort design, we measured sTM and sICAM in 317 incident CHD cases and 726 non-cases from the ARIC participants. Consistent with our previous reports, sICAM values in the upper versus the lower tertile increased the risk of CHD event by approximately 2-fold (95% confidence interval [CI], 1.46 to 2.87) whereas sTM values in the lower versus the upper tertile increased CHD risk by approximately 4-fold (95% CI, 2.80 to 5.74). Interaction between these 2 parameters was determined by weighted Cox proportional hazard regression. A significant interaction (P=0.038) was noted. Combinatorial analysis shows a significant increase in CHD risk ratio (RR) (4.66, 95% CI, 1.89 to 11.46) of the lower sTM/upper sICAM group versus the upper sTM/lower sICAM group. Individuals whose sTM values were in the upper tertile had a RR below 1, even when sICAM were in the upper tertile. The RR of lower tertile sTM was increased by sICAM in a tertile-dependent manner. Weighted Cox proportional hazard analysis shows a significant interaction between sTM and sICAM in predicting risk of CHD event. Combinatorial analysis reveals that an upper tertile sICAM had a significant increase in the risk of a CHD event only when sTM was in the lower tertile.

Distribution of Lewis (FUT3)genotype and allele: frequencies in a biethnic United States population.

The objective of the study was to examine the prevalence and distribution of four major single nucleotide polymorphisms (SNPs) (T59G, T1067G, T202C, and C314T) of the Lewis ( FUT3)gene in a biethnic United States population. This population-based cross-sectional study was based on data from the Atherosclerosis Risk in Communities (ARIC) Study, which included 761 males and females aged 45-64 years, who had no known/detected clinical atherosclerotic disease (577 Caucasians, 184 African Americans). The main outcome measures were prevalence of the Lewis genotype and allele frequencies for four SNPs of the FUT3gene. The most common genotype was the "wild type" at all four nucleotide positions ( WWWW), which was found to be present in 46.9% of ARIC participants. At least one mutant allele was detected in 51.7% of Caucasians, and 56.7% of African Americans ( P=0.59). The frequencies of mutant alleles ranged from 6.3% to 18.4% at the four FUT3gene sites examined. The distribution of the Lewis genotype and allele frequencies differed significantly by ethnicity at sites 59, 202, and 314. The prevalence of the Lewis genotype suggesting a lack of alpha(1,3/1,4) fucosyltransferase activity was 11.6% in Caucasians and 9.9% in African Americans ( P=0.67). Four specific SNPs of the Lewis genotype are common in the population at large. However, these four SNPs seem to fail to explain the majority of Lewis-negative phenotype in African Americans, given that Lewis-negative genotype prevalence was about one-third of what was expected. Use of rapid DNA sequencing and simultaneous Lewis phenotype determination could avoid the problems associated with haplotype determination and Lewis genotype grouping. Further studies testing SNPs of the Lewisgene are warranted, in particular among African Americans.

Carotid artery intimal-medial thickness distribution in general populations as evaluated by B-mode ultrasound. ARIC Investigators.

B-mode ultrasound is a widely used technique for the clinical and epidemiological assessment of carotid atherosclerosis. This article provides a description of the distribution of carotid atherosclerosis in the general population. Intimal-medial arterial wall thickness was measured by B-mode real-time ultrasound as an index of atherosclerotic involvement in the extracranial carotid arteries as part of the population-based Atherosclerosis Risk in Communities (ARIC) study. The distribution was described by race-sex strata, in which 759 to 4952 individuals were imaged depending on strata and location in the carotid system. Median wall thickness ranged between 0.5 and 1 mm at all ages; fewer than 5% of ARIC participants had values exceeding 2 mm. Individuals tended to have a larger wall thickness in the carotid bifurcation than in the common carotid artery. Internal carotid artery values were more variable, with higher proportions of both large and small wall thicknesses than in the common carotid. The proportion of individuals with a large wall thickness was greatest at the bifurcation and smallest at the common carotid artery. Men had uniformly larger wall thickness than women. Cross-sectional analysis suggests that age-related increases in wall thickness average approximately 0.015 mm/y in women and 0.018 mm/y in men in the carotid bifurcation, 0.010 mm/y for women and 0.014 mm/y for men in the internal carotid artery, and 0.010 mm/y in both sexes in the common carotid artery. Estimates provided for wall thickness percentiles can serve as "nomograms" by age, race, and sex.