Ethnic differences in carotid wall thickness. The Insulin Resistance Atherosclerosis Study

Racial differences in central blood pressure and vascular function in young men

Young African-American men have altered macrovascular and microvascular function. In this cross-sectional study, we tested the hypothesis that vascular dysfunction in young African-American men would contribute to greater central blood pressure (BP) compared with young white men. Fifty-five young (23 yr), healthy men (25 African-American and 30 white) underwent measures of vascular structure and function, including carotid artery intima-media thickness (IMT) and carotid artery β-stiffness via ultrasonography, aortic pulse wave velocity, aortic augmentation index (AIx), and wave reflection travel time (Tr) via radial artery tonometery and a generalized transfer function, and microvascular vasodilatory capacity of forearm resistance arteries with strain-gauge plethysmography. African-American men had similar brachial systolic BP (SBP) but greater aortic SBP ( P < 0.05) and carotid SBP ( P < 0.05). African-American men also had greater carotid IMT, greater carotid β-stiffness, greater aortic stiffness and AIx, reduced aortic Tr and reduced peak hyperemic, and total hyperemic forearm blood flow compared with white men ( P < 0.05). In conclusion, young African-American men have greater central BP, despite comparable brachial BP, compared with young white men. Diffuse macrovascular and microvascular dysfunction manifesting as carotid hypertrophy, increased stiffness of central elastic arteries, heightened resistance artery constriction/blunted resistance artery dilation, and greater arterial wave reflection are present at a young age in apparently healthy African-American men, and conventional brachial BP measurement does not reflect this vascular burden.

Endothelial dysfunction in African-Americans

The journey of atherosclerosis begins with endothelial dysfunction and culminates into its most fearful destination producing ischemia, myocardial infarction and death. The excess cardiovascular disease morbidity and mortality in African-Americans is one of the major public health problems. In this review, we discuss vascular endothelial dysfunction as a key element for excess cardiovascular disease burden in this target population. It can be logical window of future atherosclerotic outcomes, and further efforts should be made to detect it at the earliest in African American individuals even if they are appearing healthy as the therapeutic interventions if instituted early, might prevent the subsequent cardiac events.

Prevalence and correlates of subclinical atherosclerosis in Alaska Eskimos: the GOCADAN study

BACKGROUND AND PURPOSE

The recent increase in clinical cardiovascular disease in Alaska Eskimos suggests that changes in traditional lifestyle may have adverse public health consequences. This study examines the prevalence of subclinical vascular disease and its relation to risk factors in Alaska Eskimos.

METHODS

Participants in the population-based Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) Study underwent evaluation of cardiovascular disease risk factors and carotid ultrasound. Outcome variables were carotid intimal-medial thickness and presence and extent of atherosclerosis.

RESULTS

In multivariate analyses, intimal-medial thickness and presence and extent of atherosclerosis were all associated with traditional cardiovascular disease risk factors but not dietary intake of omega-3 fatty acids. Rates of carotid atherosclerosis were higher than those reported in 2 large population-based US studies.

CONCLUSIONS

Alaska Eskimos have similar traditional risk factors for carotid atherosclerosis as other ethnic and racial populations but have higher prevalences of atherosclerosis, possibly attributable to higher rates of smoking.

Association between depression and subclinical carotid atherosclerosis in patients with Type 1 diabetes

AIMS

Recent studies have suggested an association between depression and subclinical atherosclerosis as measured by presence of carotid atherosclerotic plaque and increased intima-media thickening in non-clinical populations. Given the high prevalence of depression in patients with Type 1 diabetes and the diabetes-related risk factors for atherosclerosis, we hypothesized that this relation might also be of special relevance in Type 1 diabetic patients.

METHODS

Intima-media thickness (IMT) and the presence of plaques in the carotid arteries were quantitatively assessed by high-resolution ultrasound in 175 adults (89 men, 86 women) with an established diagnosis of Type 1 diabetes. Having been treated for depression or current Beck Depression Inventory scores > 10 were considered to indicate depression.

RESULTS

In men, the risk of plaque was higher in depressed subjects relative to non-depressed participants after adjustment for age, smoking status, systolic blood pressure, dyslipidaemia and body mass index [odds ratio (OR) 5.19; 95% confidence interval (CI) 1.29, 20.81]. Depressed women did not have an increased risk of plaque compared with non-depressed women (OR 0.97; 95% 95% CI 0.22, 4.34). We did not observe an association between depression and IMT, in men or in women.

CONCLUSIONS

In line with previous research, our findings suggest a link between depression and subclinical atherosclerosis in Type 1 diabetic men, but not in women.

Intima-media thickness of the carotid artery and the distribution of lipoprotein subclasses in men aged 40 to 49 years between whites in the United States and the Japanese in Japan for the ERA JUMP study

In men in the post-World War II birth cohort, that is, men aged 40 to 49 years, whites in the United States had significantly higher levels of intima-media thickness of the carotid arteries (IMT) than the Japanese in Japan (Electron-Beam Tomography and Risk Assessment Among Japanese and US Men in the Post World War II Birth Cohort [ERA JUMP] study). The difference remained after adjusting for traditional risk factors. Primary genetic effects are unlikely, given the degree to which IMT is increased in the Japanese who migrated to the United States. We investigated whether the differences in the distributions of lipoprotein subclasses explain the difference in IMT between the 2 populations. We examined population-based samples of 466 randomly selected men aged 40 to 49 years (215 whites from Allegheny County, Pennsylvania, and 241 Japanese from Kusatsu, Shiga, Japan). Lipoprotein subclasses were determined by nuclear magnetic resonance (NMR) spectroscopy. The whites had significantly higher levels of large very low-density lipoprotein particles and significantly lower levels of large high-density lipoprotein particles than the Japanese, whereas the 2 populations had similar levels of small low-density lipoprotein particles. The 2 populations had similar associations of IMT with NMR lipoproteins. Adjusting for NMR lipoproteins did not attenuate the significant difference in IMT between the 2 populations (0.671 +/- 0.006 mm for the whites and 0.618 +/- 0.006 mm for the Japanese, P = .01, mean +/- SE). Differences in the distributions of NMR lipoproteins between the 2 populations did not explain the higher IMT in the whites.

Carotid stenosis in a multiethnic population

BACKGROUND

Carotid stenosis is an important, treatable cause of stroke. Several population-based studies have shown ethnic differences in the prevalence of carotid atherosclerosis. This study was performed at a large multiethnic hospital to clarify these differences.

METHODS

One thousand six carotid artery ultrasounds performed by the Department of Radiology at Los Angeles County General Hospital over a 4-year period were reviewed. Patients were classified as Caucasian (n=151), Hispanic (n=515), Black (n=173), or Asian (n=167) by self-declaration and birthplace. Carotid stenosis was defined as mild (1% to 39%), moderate (40% to 59%), severe (60% to 79%), critical (80% to 99%), or total (100%).

RESULTS

Twenty and one-half percent of Caucasian patients had greater than 59% stenosis compared with 10.1% of Hispanics, 8.7% of Blacks, and 10.7% of Asians (P<0.001). Nine and two-tenths percent of Caucasians had greater than 79% stenosis compared with 4.3% of Hispanics, 2.9% of Blacks, and 2.8% of Asians (P<0.001). There were no significant differences in age or gender representations between ethnic groups, and the indications for ordering carotid duplex sonography also did not vary by race. Caucasians and Blacks had a higher prevalence of cardiac disease, smoking, and heavy alcohol abuse. Hispanics had higher rates of diabetes.

CONCLUSIONS

These results indicate that significant differences in the degree of carotid stenosis exist among ethnic groups. Caucasian patients in our series showed a statistically higher likelihood of having a severe or critical level of stenosis. These findings may have implications for the allocation of health care resources as ethnic minorities compose a greater proportion of the population.

Recurrent stroke: the role of common carotid artery intima-media thickness

The etiology of recurrent stroke is probably multifactorial and many recurrences remain unexplained by conventional risk factors. The purpose of this study is to investigate if common carotid artery intima-media thickness (CCA-IMT), an established vascular risk factor, can predict recurrence in first-ever stroke survivors. Two hundred and eighty-four consecutive patients with a first-ever ischemic stroke were investigated with carotid ultrasonography and were screened for the first recurrent stroke up to 12 months. Sixteen (5.6%, 95% CI: 3.5-9.0%) recurrent ischemic strokes were recorded. Among demographic data, conventional vascular risk factors, presenting stroke features and ultrasonographic measurements, CCA-IMT was the only parameter that differed significantly between those who suffered a recurrent stroke and those who did not. Cox's regression analysis adjusted for confounding factors, showed that CCA-IMT was the only independent predictor of stroke recurrence (HR 1.65; 95% CI: 1.11-2.46%). We propose that CCA-IMT measurements may help to identify stroke patients at higher risk for recurrence and to plan secondary prevention strategies.

Coronary calcification is more predictive of carotid intimal medial thickness in black compared to white middle aged men

BACKGROUND

Race-specific data for the association between coronary artery calcification (CAC) and carotid intimal medial thickness (IMT) are limited. We sought to compare black-white specific associations of these two measures.

METHODS

We conducted a population-based study of 379 randomly selected men aged 40-49 years (84 black and 295 white) from Allegheny County, US (2004-2006). Agatston CAC score was evaluated by electron-beam tomography and carotid IMT was evaluated by ultrasonography.

RESULTS

Compared to white men, black men had similar prevalence of CAC (p=0.56) and higher total carotid IMT (p<0.001). In black and white men, CAC score had significant positive correlations with total carotid IMT (r=0.47 and r=0.24, respectively, p<0.001 for both) as well as the IMT for the common carotid artery (CCA), internal carotid artery and carotid bulb. The associations of CAC with total and CCA IMT were significantly stronger in black (beta=0.07 and beta=0.05, respectively) than white men (beta=0.03 and beta=0.01, respectively) after adjustment for traditional coronary risk factors (p=0.046 and p=0.036, respectively).

CONCLUSIONS

In black and white middle aged men, CAC score had significant positive correlations with total and segmental carotid IMT. CAC was more predictive of total and CCA IMT in black than white men independent of coronary risk factors.

Prevalence and clinical correlates of mitral annulus calcification in Hispanics and non-Hispanic whites

BACKGROUND

Data about mitral annulus calcification (MAC) are sparse in Hispanics. We compare prevalence and clinical correlates of MAC in Hispanics and non-Hispanic whites.

METHODS

We reviewed echocardiograms and clinical data of 337 Hispanics and 279 non-Hispanic whites, age 45 to 75 years. In cross-sectional data, prevalence and interrelationships of MAC, coronary heart disease (CHD), and risk factors were compared using multivariable logistic regression.

RESULTS

In Hispanics, MAC was significantly associated with CHD (odds ratio [OR] = 2.06, confidence interval [CI] = 1.09-3.87), age (OR = 1.73, CI = 1.21-2.49), female sex (OR = 1.87, CI = 1.01-3.47), smoking (OR = 1.80, CI = 1.01-3.24), and having multiple (>2) risk factors (OR = 3.43, CI = 2.66-4.43). In non-Hispanic whites, MAC was associated with CHD (OR = 4.24, CI = 2.00-8.98), age (OR = 2.87, CI = 1.82-4.50), and having multiple risk factors (OR = 3.59, CI = 2.7-4.77). There were no significant ethnic differences in prevalence of MAC.

CONCLUSIONS

Among Hispanics referred for echocardiography, MAC is associated with CHD and risk factors.

Thematic review series: Patient-Oriented Research. Imaging atherosclerosis: state of the art

The ability to image obstructive arterial disease brought about a revolution in clinical cardiovascular care; the development of newer technologies that image arterial wall thicknesses, areas, volumes, and composition allows valid imaging of atherosclerosis for the first time. Development of noninvasive imaging of atherosclerosis has further led to a quantum shift in research in the field by enabling the study of asymptomatic populations and thus allowing investigators to focus on preclinical disease without the many biases associated with the study of symptomatic patients. These noninvasive investigations have broad implications for clinical care as well. Coronary angiography, computed tomographic (CT) imaging of coronary calcium, intravascular ultrasound, multidetector CT angiography, B mode ultrasound of the carotid arteries, and MRI of the carotid arteries all have unique strengths and weaknesses for imaging atherosclerosis. Certain of these techniques are extremely useful as outcome variables for clinical trials, and others are uniquely useful as predictors of the risk of cardiovascular disease. All are informative in one way or another with regard to the role of plaque remodeling and composition in disease causation. CT and MRI technology are advancing very rapidly, and research and clinical uses of these imaging modalities promise to further advance our understanding of atherosclerosis and its prevention.

An evaluation of the International Diabetes Federation definition of metabolic syndrome in Chinese patients older than 30 years and diagnosed with type 2 diabetes mellitus

The objective of the study was to determine the most accurate metabolic syndrome (MS) definition among the definitions proposed by the International Diabetes Federation (IDF), the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATPIII]), and the World Health Organization (WHO) and to evaluate the cutoff point of waist circumference using the IDF definition for optimally defining MS in the Chinese population. One thousand thirty-nine Chinese patients older than 30 years and diagnosed with type 2 diabetes mellitus were investigated by randomized cluster sampling in the Shanghai downtown, and 1008 patients were analyzed in this study. Body mass measurements, resting blood pressure, fasting blood measures, and carotid atherosclerotic measurements including common carotid artery intima-media thickness (IMT) and carotid plaque were investigated. The IDF definition was compared with the other 2 definitions, and the carotid atherosclerosis was evaluated among the patients according to these definitions. (1) The MS prevalence was 50.0%, 55.7%, and 70.0% under the IDF, ATPIII, and WHO definitions, respectively. (2) The percentage of all the participants categorized as either having or not having the MS was 69.9% (under the IDF and ATPIII definitions) and 70.2% (under the IDF and WHO definitions). (3) Common carotid artery IMT of patients with MS determined by the IDF definition was thicker than those determined by the WHO and ATPIII definitions, and the percentage of carotid plaque of patients with MS determined by the IDF definition was greater than those determined by the WHO and ATPIII definitions. (4) When the cutoff point of waist circumference in men determined by the IDF definition was modified from 90 to 85 cm, common carotid artery IMT of the emerging male patients with MS was thicker than that of the male patients with MS determined by the original IDF definition. In conclusion, the prevalence of MS was 50.0%, 55.7%, and 70.0% under the IDF, ATPIII, and WHO definitions, respectively. The preferable IDF definition served as a better predictor of cardiovascular disease risk in the Chinese patients diagnosed with type 2 diabetes mellitus compared with the ATPIII and WHO definitions. The modified cutoff point of waist circumference in men under the IDF definition specific for the Chinese population (from 90 to 85 cm) might be more suitable for predicting atherosclerosis.

The role of inheritance and environment in predisposition to vascular disease in people of African descent

OBJECTIVES

This study sought to compare vascular reactivity and carotid intima media thickness (CIMT) between Afro-Caribbean people in the United Kingdom (UK) and the West Indies and Afro-Caribbean and Caucasian people in the UK.

BACKGROUND

Attenuated vascular reactivity and increased CIMT in black patients is seen as evidence for predisposition to vascular disease, but no comparisons exist between Afro-Caribbean people in different settings, which can provide insight into non-inherited determinants of increased ethnic susceptibility.

METHODS

A representative community sample of 81 healthy Afro-Caribbean people and 101 Caucasian people in the UK was compared with 197 matched Afro-Caribbean people in Jamaica. Small vessel reactivity was assessed by measuring the absolute change from baseline in the reflection index (RI) of the digital volume pulse during intravenous infusion of albuterol (5 microg/min, DeltaRI(ALB)) and glyceryl trinitrate (5 microg/min, DeltaRI(GTN)). The CIMT was measured ultrasonographically in the distal 1 cm of the common carotid artery.

RESULTS

Mean DeltaRI(ALB) was 4.2 percentage points (95% confidence interval [CI], 2.3 to 6.1, p < 0.001) lower in UK Afro-Caribbean people compared with Jamaican Afro-Caribbean people and 2.6 percentage points (95% CI, 0.4 to 4.7, p = 0.02) lower compared with Caucasian people, after adjusting for vascular risk profile. Adjusted mean CIMT of UK Afro-Caribbean people was 0.13 mm (95% CI, 0.08 to 0.17, p < 0.001) greater compared with Jamaican Afro-Caribbean people and 0.05 mm (95% CI, 0.01 to 0.10, p = 0.02) greater compared with Caucasian people.

CONCLUSIONS

Healthy UK Afro-Caribbean people have greater and Jamaican Afro-Caribbean people have less impairment of vascular reactivity and intima media thickness compared with UK Caucasian people, suggesting that potentially modifiable environmental interactions may contribute to excess vascular disease in Afro-Caribbean people.

Diabetes in the Hispanic or Latino population: genes, environment, culture, and more

The Hispanic or Latino population is the largest minority group in the United States, currently representing 13.7% of the total U.S. population. Hispanics or Latinos usually suffer from higher rates of type 2 diabetes, obesity, metabolic syndrome, and their multiple vascular complications. Inadequate nutrition and reduced physical activity in the setting of an increased genetic predisposition to type 2 diabetes have contributed to the inexorable rise in metabolic abnormalities in Hispanics in the United States, which now affect many children and adolescents. It is evident that multiple medical, cultural, and socioeconomic factors influence the development of diabetes, its course, and its consequences. Our health care system is barely prepared to face the challenge of managing diabetes in this high-risk group. Culturally oriented clinical care, education, outreach and research programs are needed to better identify the challenges to create opportunities to improve the lives of Hispanics or Latinos with diabetes or at risk for the disease.

Common carotid artery intima-media thickness for the risk assessment of lacunar infarction versus intracerebral haemorrhage

BACKGROUND AND PURPOSE

Arterial hypertension is the major risk factor for intracerebral haemorrhage (ICH) and lacunar infarction (LI) and both types of cerebral lesions originate from pathology of the same deep perforating small arteries. We aimed to evaluate the relationship between vascular risk factors including common carotid artery intima-media thickness (CCA-IMT) with LI versus ICH.

METHODS

We prospectively collected data from 159 first ever stroke patients (67 cases with ICH and 92 cases with LI) with documented history of hypertension. All subjects underwent B-mode ultrasonographic measurements of the CCA-IMT. Logistic regression modelling was used to determine the factors (established vascular risk factors, severity and duration of hypertension, concomitant medications and CCA-IMT) that may significantly differentiate LI from ICH.

RESULTS

Patients with LI had significantly (p=0.002) larger CCA-IMT values (0.926 mm, 95% CI: 0.881-0.971) than subjects with ICH (0.815 mm, 95% CI: 0.762-0.868) even after adjusting for baseline characteristics and cardiovascular medications. The multivariate logistic regression procedure selected CCA-IMT, diabetes mellitus and hypercholesterolaemia as the only independent factors able to discriminate between LI and ICH. The risk for LI versus ICH increased continuously with increasing CCA-IMT. For each increment of 0.1 mm in CCA-IMT the probability of suffering from LI versus ICH increased by 36.6% (95 % CI: 13%-65.2%, p=0.001) even after adjustment for cardiovascular risk factors.

CONCLUSIONS

Increased CCA-IMT values are a factor favouring LI over ICH in hypertensive patients. The measurement of CCA-IMT may be a useful non-invasive diagnostic tool for the risk assessment of LI with respect to ICH in such patients.

Hypertension and subclinical carotid atherosclerosis in a suburban general population in China

OBJECTIVE

To explore the association of hypertension and carotid atherosclerosis in a general population in China.

METHODS

A population-based cardiovascular epidemiology survey was performed in a total of 1198 residents in suburban Beijing, 426 men and 776 women aged 43-73 years. Carotid plaque and the intima-media thickness were measured using duplex ultrasound.

RESULTS

The intima-media thickness, the prevalence of plaque and the number of plaques were found significantly positively related to hypertension categories (optimal, normal, high-normal, stage 1, 2 and 3 hypertension, according to The Chinese Hypertension Guidelines) as well as to the duration of hypertension, with a dose-response pattern in both genders (trend test, P < 0.01). After adjustment for age, total cholesterol, high-density lipoprotein-cholesterol, fasting glucose, smoking, antihypertensive treatment, stroke, myocardial infarction and angina, the relationship still existed, particularly in women. The associations of carotid atherosclerosis with duration of hypertension were weakened by further adjustment for systolic blood pressure, diastolic blood pressure or hypertension categories.

CONCLUSION

Hypertension was associated with subclinical carotid atherosclerosis. A prolonged course of the disease may aggravate the carotid atherosclerosis, independently of the level of blood pressure.

Significance of the intima-media thickness of the thoracic aorta in patients with coronary atherosclerosis

BACKGROUND

The prevalence and clinical significance of atherosclerotic aortic disease have now been documented in a variety of patient populations by use of transesophageal echocardiography (TEE). There are many reports that atherosclerotic aortic plaques detected by TEE are a marker for coronary artery disease (CAD).

HYPOTHESIS

The study was undertaken to evaluate the significance of the intima-media thickness (IMT) and formation of atherosclerotic plaques of the thoracic aorta (TA) in patients with CAD, especially in terms of a correlation between the IMT of the TA and the extent of coronary atherosclerosis.

METHODS

The IMT of the TA was measured using TEE. The study population comprised 100 patients (68 men, mean age 59 years). The extent of coronary atherosclerosis was divided into four groups (0, 1, 2, 3) according to the number of coronary arteries narrowed > or = 50%.

RESULTS

There was no significant difference in the IMT of the ascending TA according to the presence of significant (> 50% narrowed) coronary stenosis, but there was a significant difference in the IMT of the descending TA (1.39 vs. 1.88 mm, p = 0.005). There was a significant correlation between the extent of coronary atherosclerosis and the IMT of the ascending and descending TA (r = 0.24, p < 0.05; r = 0.352, p < 0.001, respectively). The plaques in the TA were seen in 7, 41, 52, and 65% of patients in Groups 0, 1, 2, and 3, respectively. Among atherosclerosis risk factors, hyperlipidemia was the only factor analyzed that affected the IMT of the descending TA (2.11 vs. 1.78 mm, p < 0.05).

CONCLUSION

The IMT of the TA correlates significantly with coronary atherosclerosis, and correlation of the descending TA IMT with coronary atherosclerosis is better than that of ascending TA IMT. Age is associated with coronary atherosclerosis, and TA IMT and hyperlipidemia are associated with descending TA IMT. Therefore, although TEE is not recommended for measuring TA IMT or for evaluating aortic plaques in patients with CAD, measurement of TA IMT as well as carotid artery IMT is very helpful for understanding the extent of coronary atherosclerosis.

The relation of obesity throughout life to carotid intima-media thickness in adulthood: the Bogalusa Heart Study

OBJECTIVE

Although obese children are at increased risk for coronary heart disease in later life, it is not clear if this association results from the persistence of childhood obesity into adulthood. We examined the relation of adiposity at various ages to the carotid intima-media thickness (IMT) at age 35 y.

DESIGN

Prior to the determination of IMT by B-mode ultrasound, subjects (203 men, 310 women) had, on average, six measurements of body mass index (BMI) and triceps skinfold thickness (TSF) between the ages of 4 and 35 y. Mixed regression models for longitudinal data were used to assess the relation of these characteristics to adult IMT.

RESULTS

Overall, adult IMT was associated with levels of both BMI and TSF (P<0.001), with the magnitudes of the associations with childhood adiposity comparable to those with adult levels of BMI and TSF. Furthermore, adult obesity modified the association between childhood adiposity and IMT: high IMT levels were seen only among overweight (BMI > or =95th percentile) children who became obese (BMI > or =30 kg/m2) adults (P<0.01 for linear trend). In contrast, IMT levels were not elevated among (1) overweight children who were not obese in adulthood, or among (2) thinner children who became obese adults.

CONCLUSIONS

These results emphasize the adverse, cumulative effects of childhood-onset obesity that persists into adulthood. Since many overweight children become obese adults, the prevention of childhood obesity should be emphasized.

Genetic determinants of arterial calcification associated with atherosclerosis

Increasing research interest has focused on arterial calcification in the setting of atherosclerosis. Many features of atherosclerosis-related calcification provide useful clinical information. For example, calcium mineral deposits frequently form in atherosclerotic plaque, and intimal arterial calcification can be used as a surrogate marker for atherosclerosis; also, calcium deposits are readily and noninvasively quantified, which is useful because greater amounts of coronary calcification predict a higher risk of myocardial infarction and death. Several mechanisms leading to calcification associated with atherosclerosis have been proposed; however, no direct testing of proposed mechanisms has yet been reported. Studies in genetically altered animals and in humans have shed light on potential genetic determinants, which in turn could form the basis for a more comprehensive understanding of the factors affecting calcification within plaque and the associated pathobiologic implications. We review proposed molecular and cellular mechanisms of atherosclerosis-associated arterial calcification, summarize genetic influences, and suggest areas in which further investigation is needed. Understanding the molecular and genetic determinants of specific structural plaque components such as calcification can provide a solid foundation for the development of novel therapeutic approaches to favorably alter plaque structure and minimize vulnerability to arterial rupture.

Childhood cardiovascular risk factors and carotid vascular changes in adulthood: the Bogalusa Heart Study

CONTEXT

Carotid artery intima-media thickness (IMT) is associated with cardiovascular risk factors and is recognized as an important predictive measure of clinical coronary atherosclerosis events in middle-aged and elderly populations. However, information on the association of carotid IMT in young adults with different risk factors measured in childhood, adulthood, or as a cumulative burden of each of the risk factors measured serially from childhood to adulthood is limited.

OBJECTIVE

To examine the association between carotid IMT in young adults and traditional cardiovascular risk factors measured since childhood.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study of 486 adults aged 25 to 37 years from a semirural black and white community in Bogalusa, La (71% white, 39% men), who had at least 3 measurements of traditional risk factors since childhood, conducted between September 1973 and December 1996.

MAIN OUTCOME MEASURE

Association of carotid IMT with risk factors, including systolic blood pressure, lipoprotein levels, and body mass index.

RESULTS

Male vs female (0.757 mm vs 0.719 mm) and black vs white (0.760 mm vs 0.723 mm) participants had increased carotid IMT (P<.001 for both). In multivariable analyses, significant predictors for being in top vs lower 3 quartiles of carotid IMT in young adults were childhood measures of low-density lipoprotein cholesterol (LDL-C) level (odds ratio [OR], 1.42, corresponding to 1-SD change specific for age, race, and sex; 95% confidence interval [CI], 1.14-1.78) and body mass index (BMI; OR, 1.25; 95% CI, 1.01-1.54); adulthood measures of LDL-C level (OR, 1.46; 95% CI, 1.16-1.82), high-density lipoprotein cholesterol (HDL-C) level (OR, 0.67; 95% CI, 0.51-0.88), and systolic blood pressure (OR, 1.36; 95% CI, 1.08-1.72); and long-term cumulative burden of LDL-C (OR, 1.58; 95% CI, 1.24-2.01) and HDL-C (OR, 0.75; 95% CI, 0.58-0.97) levels measured serially from childhood to adulthood. An increasing trend in carotid IMT across quartiles of LDL-C level measured in childhood was observed, with a mean value of 0.761 mm (95% CI, 0.743-0.780 mm) for those at the top quartile vs 0.724 mm (95% CI, 0.715-0.734 mm) for those in the lower 3 quartiles (P<.001).

CONCLUSIONS

Childhood measures of LDL-C level and BMI predict carotid IMT in young adults. The prevention implications of these findings remains to be explored.

Apolipoproteins and carotid artery atherosclerosis in an elderly multiethnic population: the Northern Manhattan stroke study

The association of apolipoproteins A-I and B (apo A-I and apo B) with cardiovascular disease has been studied in younger populations, but there is sparse information in the elderly. We determined whether apo A-I and apo B were associated with carotid artery atherosclerosis (CAA) in 507 stroke-free elderly community residents (mean age 70.1+/-11.7 years, 60% women, 41% Hispanics, 30% African American, 28% Caucasian). CAA severity was normal (no plaque or carotid stenosis) in 39%, mild (maximum plaque thickness < or =1.8 mm or carotid stenosis <40%) in 25%, and moderate/severe (maximum plaque thickness >1.8 mm or carotid stenosis > or =40%) in 36%. CAA severity increased with age in all race/ethnic groups (P<0.01). CAA was similar among African Americans and Caucasians, but less in Hispanics (age adjusted OR: 0.5, CI: 0.4-0.8). apo A-I <1.2 g/l (OR: 2.0, CI: 1.0-3.3) and apo B > or =1.4 g/l (OR: 2.0, CI: 1.1-3.6) were associated with moderate-severe CAA. An apo B/apo A-I ratio > or =1 was associated with moderate-severe CAA (OR: 2.4, CI: 1.3-4.4), and the association varied by race (Hispanics OR: 4.3, CI: 1.8-10; non-Hispanics, OR: 1.4, CI: 0.6-3.2). Total cholesterol, triglycerides and low density lipoprotein cholesterol were not associated with moderate-severe CAA, while high density lipoprotein cholesterol was protective (OR: 0.4, CI: 0.2-0.8). Thus, in an elderly population, apo A-I and B were determinants of moderate-severe CAA, and the degree of association varied by race/ethnicity

Impact of multiple coronary risk factors on the intima-media thickness of different segments of carotid artery in healthy young adults (The Bogalusa Heart Study)

Although risk factors for coronary artery disease are also associated with increased carotid artery intima-media thickness (IMT) as measured by B-mode ultrasonography in middle-aged and older persons, information on the impact of multiple risk factors on the IMT of different segments of the carotid artery in young adults is limited. This relation was examined in a sample of 518 black and white subjects (mean age 32 years; 71% white, 39% male) enrolled in the Bogalusa Heart Study. IMT was thicker and more skewed in the bulb compared with other carotid segments. Race differences (blacks more than whites) were noted for the common carotid (p <0.001) and carotid bulb (bifurcation) IMT (women only, p <0.001). Men had a greater IMT in the common carotid (p <0.05), internal carotid (p <0.05), and carotid bulb (whites only, p <0.001). In a multivariate analysis, systolic blood pressure, race, age, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol weree entered into a model in that order and accounted for the 16.7% variance in the common carotid IMT; age, systolic blood pressure, HDL cholesterol, LDL cholesterol, race, and insulin levels explained the 19.4% variance in the carotid bulb IMT. Gender and body mass index (BMI) accounted for the 4.7% variance in the internal carotid IMT. Increases in IMT with increasing number of risk factors (cigarette smoking, higher total cholesterol to HDL cholesterol ratio, higher systolic blood pressure, greater waist circumference, and higher insulin level) were noted for the common carotid and carotid bulb segments (p for trend <0.001 for both). The observed deleterious trend of increasing IMT at different carotid segments with increasing number of risk factors in free-living, asymptomatic young subjects underscores the importance of profiling multiple risk factors early in life. Ultrasonography of carotid arteries, especially at the bifurcation, may be helpful along with measurements of risk factors for evaluation of asymptomatic atherosclerotic disease.

Is insulin sensitivity a causal intermediate in the relationship between alcohol consumption and carotid atherosclerosis?: the insulin resistance and atherosclerosis study

OBJECTIVE

A J-shaped association has been demonstrated between alcohol consumption and atherosclerosis. Insulin resistance, also a risk factor for atherosclerosis, has been shown to have a similar J-shaped association with alcohol intake. This raises the question of whether insulin sensitivity (S(I)) is a causal intermediate in the alcohol-atherosclerosis relationship.

RESEARCH DESIGN AND METHODS

The Insulin Resistance Atherosclerosis Study was a multicenter cohort study designed to investigate relationships among S(I), risk factors for cardiovascular disease, and carotid artery atherosclerosis. Using regression analysis, we tested whether adjustment for S(I) attenuated the alcohol-atherosclerosis relationship observed at baseline.

RESULTS

A J-shaped association was observed between alcohol consumption and common carotid artery intimal medial thickness. The protective aspect of the alcohol-atherosclerosis relationship was attenuated by 25% after the adjustment for S(I). However, an interaction was observed between alcohol consumption and glucose tolerance (GT) status. In comparison with never drinkers, all levels of alcohol consumption were associated with less atherosclerosis in participants with normal GT status. Participants with impaired GT status (but not diabetes) demonstrated a J-shaped alcohol-atherosclerosis association. All levels of alcohol consumption were associated with more atherosclerosis in participants with diabetes.

CONCLUSIONS

S(I) may be a causal intermediate at protective levels of alcohol intake, but an alcohol-GT interaction precluded a definitive conclusion. Moderate alcohol consumption may increase the risk of atherosclerosis in people with diabetes. These findings contrast with previous reports and do not support current recommendations regarding moderate alcohol consumption in people with diabetes. More research is needed to clarify this issue.

Ethnic differences in carotid and left ventricular hypertrophy

OBJECTIVES

Afro-Caribbean subjects have a higher prevalence of hypertension, a lower prevalence of ischaemic heart disease and a higher premature mortality compared to White Europeans. Left ventricular hypertrophy (LVH) is also more prevalent in Afro-Caribbeans even at similar levels of blood pressure. It is widely believed that carotid artery intima-media thickening (IMT) represents an early marker for the development of atheroma, and carotid IMT and LVH are associated in White populations. Whether the relationship between carotid IMT and LVH is similar in Black subjects is unknown.

METHODS

Thirty-eight subjects were studied using carotid and femoral ultrasonography and echocardiography; 19 Afro-Caribbean and 19 White European subjects were matched for age, sex and mean 24 h systolic blood pressure.

RESULTS

The Afro-Caribbean group had a significantly greater left ventricular mass index (LVMI) compared to the White European: 136.4 +/- 6.1 versus 112.4 +/- 6.2 g/m2, P < 0.01. However, carotid IMT, carotid diameter, femoral IMT and femoral diameter were similar between the groups: 0.75 +/- 0.02 versus 0.77 +/- 0.04 mm, 6.54 +/- 0.15 versus 6.56 +/- 0.16 mm, 0.66 +/- 0.03 versus 0.68 +/- 0.03 mm and 8.40 +/- 0.33 versus 8.25 +/- 0.23 mm, respectively.

CONCLUSIONS

Afro-Caribbean subjects with similar blood pressures have similar mean carotid and femoral IMTs compared to White Europeans, in spite of marked differences in LVMI. Whether this reflects a discrepancy in the degree of cardiovascular risk for similar levels of LVMI or whether this is a reflection of an altered pattern of target organ damage associated with hypertension in Afro-Caribbean subjects is unclear.

Stroke in African Americans

There is an excess burden of cerebrovascular disease in African Americans. This article will define possible reasons for excess stroke risk, review racial differences in stroke subtype and stroke prevention programs in the African American Community, and delineate sequelae of stroke. The authors provide insights about stroke prevention in African Americans and highlight challenges to reduce the burden of cerebrovascular disease in this high-risk group.

Racial differences in aortic stiffness in normotensive and hypertensive adults

OBJECTIVE

To investigate whether differences exist in the mechanical properties of large arteries between white and black subjects.

DESIGN

Eighty-two white (49 normotensive and 33 untreated hypertensive) and 38 black (24 normotensive and 14 untreated hypertensive) adult male volunteers were studied in a cross-sectional study.

METHODS

Carotid-femoral pulse wave velocity was measured as an index of arterial stiffness, using a recently developed non-invasive automatic device, and compared between white and black subjects before and after the adjustment for age. The slope of regressions for pulse wave velocity and systolic blood pressure were also compared between racial groups.

RESULTS

In the normotensive group, white subjects presented higher mean values of pulse wave velocity than blacks while the opposite behavior was found in the hypertensive group. After adjustment for age, significant differences in pulse wave velocity between whites and blacks became evident in the normotensive (whites 8.15 +/- 0.04 versus blacks 7.75 +/- 0.02 m/s; P < 0.001) and hypertensive (whites 8.88 +/- 0.02 versus blacks 9.30 +/- 0.17 m/s; P < 0.001) groups. Linear regression analysis for age-adjusted pulse wave velocity and systolic blood pressure showed that the slope was significantly greater in blacks than in whites (0.040 +/- 0.002 versus 0.019 +/- 0.001 m/s; P < 0.001).

CONCLUSION

These data indicate that there is a greater pressure-dependent increase in aortic stiffness in blacks than in whites. This finding points towards major differences in mechanical properties of large arteries between these racial groups.

Effect of intensive diabetes treatment on carotid artery wall thickness in the epidemiology of diabetes interventions and complications. Epidemiology of Diabetes Interventions and Complications (EDIC) Research Group

The Epidemiology of Diabetes Interventions and Complications (EDIC) is a multicenter longitudinal observational study of the Diabetes Control and Complications Trial (DCCT) cohort. One of the major objectives of EDIC is to study the development and progression of atherosclerotic cardiovascular disease in type 1 diabetes. In this study, we evaluated the role of cardiovascular risk factors and antecedent therapy in the DCCT on carotid intima-media wall thickness (IMT) in type 1 diabetes. At approximately 18 months after the end of the DCCT, high-resolution B-mode ultrasonography was used to assess the carotid arteries of 1,325 patients with type 1 diabetes, 19-51 years of age, with duration of diabetes ranging from 6.3 to 26.1 years. An age- and sex-matched nondiabetic population (n = 153) was studied with the same protocol. The ultrasound protocol was carried out in 28 EDIC clinics by centrally trained and certified sonographers using one of three scanning systems. Determination of IMT from videotaped images was performed by a single reader at the Central Ultrasound Reading Unit. Univariate associations with greater IMT were strongest for older age and longer diabetes duration, greater waist-to-hip ratio (men only), higher blood pressure, higher LDL cholesterol, and smoking. The DCCT therapy group (intensive versus conventional) and HbA1c, measured at the time of the ultrasound or the mean HbA1c during the DCCT, were not significantly related to IMT. Multivariate analyses suggest that age, height, smoking, and BMI were the major predictors of common carotid IMT, whereas age, smoking, and LDL cholesterol predicted internal carotid IMT. There were significant differences between the IMT values of the internal carotid artery in the EDIC male cohort and similarly aged male nondiabetic control subjects. There were no significant differences between the IMT values in the EDIC female cohort and similarly aged female nondiabetic control subjects. At this point in the planned 10-year follow-up of the DCCT cohort, neither intensive therapy nor HbA1c level appears to influence the early signs of atherosclerosis. Traditional risk factors, including age, smoking, and LDL cholesterol, were related to IMT. As the cohort is only now entering the age interval during which rapid progression and clinical expression of atherosclerosis are expected, further follow-up will help to determine the role of hyperglycemia, and its interaction with other risk factors, on the development of atherosclerosis.