doi: 10.1161/hs0901.095601
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(Stroke. 2001;32:1953.)
© 2001 American Heart Association, Inc.
Original Contributions |
Site-Specific Atherosclerotic Plaques in the Carotid Arteries of Middle-Aged Women From Southern Italy
Associations With Traditional Risk Factors and Oxidation Markers
From the Dipartimento di Medicina Clinica e Sperimentale (P.R., S.P., G.C., A.I., M.M.) and Dipartimento di Biochimica e Biotecnologie Mediche (M.A.B., A.P., L.S., F.S.), Facolta’ di Medicina e Chirurgia, Universita’ di Napoli Federico II, Naples, Italy; Unita’ di Epidemiologia, Istituto Nazionale per la Ricerca sul Cancro, Naples, Italy (E.C.); Centro di Riferimento Oncologico della Basilicata, Rionero in Vulture, Potenza, Italy (R.G.); and Division of Vascular Ultrasound Research, School of Medicine, Wake Forest University, Winston-Salem, NC (M.G.B.).
Reprint requests to Paolo Rubba, MD, Clinica Medica, Policlinico, Facolta’ di Medicina e Chirurgia, Universita’ di Napoli Federico II, Via S. Pansini 5, 80131 Naples, Italy. E-mail rubba{at}unina.it
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Abstract |
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Background and Purpose—— Studies on cardiovascular disease have preferentially involved men because of the lower frequency of the disease in preelderly women. The aim of this analysis was to examine, with the use of a standardized ultrasound protocol, a cohort of women to differentiate early atherosclerotic lesions in different carotid segments in relation to traditional (lipoprotein abnormalities, high blood pressure, cigarette smoking) and nontraditional (oxidation markers) cardiovascular risk factors.
Methods—— More than 5000 clinically healthy, middle-aged women (n=5062; age range, 30 to 69 years) living in the area of Naples in southern Italy participated in the Progetto Atena, a population-based study on the etiology of cardiovascular disease and cancer in the female population. A subsample of 310 participants underwent high-resolution B-mode ultrasound to assess intima-media thickness of common carotid artery and carotid bifurcation.
Results—— Early atherosclerotic plaques (intima-media thickness >1.2 mm) were detected within the common carotid arteries in 37 women, in the carotid bifurcations in 77 women, and in both sites in 91 women. After age adjustment, common carotid plaques were found to be associated with higher systolic blood pressure (143 versus 138 mm Hg; P<0.05) and higher body mass index (29 versus 27 kg/m2; P<0.01), while lesions at the carotid bifurcations were associated with higher LDL cholesterol (4.3 versus 3.8 mmol/L; P<0.01) and with smoking habit. Multivariate odds ratios for the presence of common carotid plaques were related to antibodies against oxidized LDL (odds ratio, 2.72; 95% CI, 1.46 to 5.07), and those for plaques at the bifurcation were related to lipid peroxides (odds ratio, 1.90; 95% CI, 1.04 to 3.47), and both relationships were independent of age, LDL cholesterol concentrations, body mass index, smoking habit, and systolic blood pressure.
Conclusions—— In a cohort of clinically healthy, middle-aged women, we found a site-specific association of traditional risk factors and oxidation markers with early atherosclerotic lesions in arterial segments differing in geometry, shear stress, extracellular matrix composition, and cell type populations.
Key Words: atherosclerosis • oxidized low density lipoprotein • risk factors • ultrasonics • women
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Introduction |
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Decades of epidemiological research have provided substantial information on risk factors for cardiovascular disease.1 However, studies have preferentially involved men because of the lower frequency of the disease in preelderly women.
Epidemiological studies using high-resolution ultrasound have provided information on the prevalence of atherosclerosis extent and severity.2–4 Noninvasive carotid artery end points are among the best predictors of the clinical atherosclerotic status.5–7 B-mode ultrasound imaging has also been used to evaluate prospectively the natural history of peripheral atherosclerosis evolution by monitoring lesion growth over time8 and its stabilization9–12 in selected groups of patients. B-mode ultrasound offers the opportunity to examine the atherogenic associations of risk factors in different populations and the efficacy of medical interventions aimed at slowing disease progression. This method allows the quantitative measurement of an end point that is closely related to the underlying disease, ie, combined intima-media thickness (IMT).13
In addition to traditional risk factors associated with the development and progression of atherosclerosis, oxidized lipoproteins have attracted much attention.14–17 Oxidized LDL has been reported to stimulate macrophage transformation into foam cells, functional changes in endothelial cell, and immune responses involving autoantibodies and immunocomplexes. All these processes are thought to be involved in the early phases of development of atherosclerotic lesions.18
The aim of this study was to examine, with a standardized ultrasound protocol, a cohort of women to differentiate early atherosclerotic lesions in different carotid segments in relation to traditional (lipoprotein abnormalities, high blood pressure, cigarette smoking) and nontraditional (oxidation markers) cardiovascular risk factors.
The present analysis was done in a geographic area (the Mediterranean basin) where some loss of the traditional Mediterranean advantage for coronary heart disease has been reported and where mortality data for stroke have always been less favorable.19
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Subjects and Methods |
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Selection of Subjects
More than 5000 clinically healthy, middle-aged women (n=5062; age range, 30 to 69 years) living in the area of Naples participated in the Progetto Atena study.20 The general objective of this project is to investigate the causes of those chronic diseases that have a major impact on the female population. Individuals with a previous diagnosis of myocardial infarction, stroke, or major cancers were not included. Subjects with acute disease affecting blood and urine biochemistry were invited to delay their participation. During a 6-month period, the older 3 of 10 daily participants were offered an ultrasound examination and additional biochemical tests, free of charge. Of those 400 women who were invited, 310 accepted the additional investigations and constituted the present cohort. After age adjustment, there were no statistically significant differences (Table 1) in cardiovascular risk factor profile between the whole cohort of Progetto Atena and the subset (our sample) who elected to undergo an ultrasound examination and oxidation marker assays.
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The study was approved by the ethical committees of the institutions involved, and the subjects recruited gave their informed consent.
Anthropometry, Blood Pressure, and Biochemical Analyses
Body mass index (BMI) was calculated according to the following formula: BMI=Weight (kg)/Height2 (m2). Procedures for blood pressure measurements and training and supervision of observers were similar to those previously described.21 Lifestyle questionnaires were based on the questionnaires used in major Italian population studies of cardiovascular disease.
Blood was withdrawn between 8 and 9:30 AM after an overnight fast, and serum and plasma samples were prepared in part to be immediately analyzed and in part to be stored in liquid nitrogen. Serum samples were processed for total cholesterol and triglyceride assays by enzymatic methods.22,23 HDL cholesterol was precipitated by phosphotungstate.24 LDL cholesterol was calculated according to the Friedewald formula: LDL Cholesterol=Total Cholesterol-(Triglycerides/5+HDL Cholesterol).
Serum IgG antibody titer against oxidized LDL was determined in duplicate by an ELISA on microwells coated with Cu2+ oxidized LDL (o-LAB-ELISA kit, Biomedica). Imprecision of the method was evaluated on sera at both low and high contents of oxidized LDL and was always <10%.
The measurement of thiobarbituric acid reactive substances (TBARS) was used as a screening method for lipid peroxidation. We used a modified TBA assay25 that minimizes artifactual oxidative degradation of lipids during the assay. The inclusion in the test of a large amount of the antioxidant butylated hydroxytoluene (BHT) prevents the formation and decomposition of lipid peroxides during the acidic heating stage of the assay. Moreover, interference by plasma carbohydrates26 can be reduced by lowering the assay temperature from 90°C to 80°C. Patients’ plasma samples were heated with TBA in the presence of 3 mmol/L BHT. The absorption spectra of the n-butanol extracts of the reaction mixtures were recorded between 650 and 450 nm: the absorbance at 535 nm minus the absorbance at 572 nm was taken as a measure of the TBARS adducts. The results were quantified on the basis of a calibration curve obtained with standard malondialdehyde, the main product of lipid peroxidation.
The total radical trapping activity of plasma (TRAP), which is indicative of plasma antioxidant potential, was measured by a spectrophotometric end point method27,28 on a Cobas Fara centrifugal analyzer (Roche). Briefly, myoglobin in the ferric (FeIII) state was activated by hydrogen peroxide, resulting in a radical species in which the haem iron is in the ferryl form (FeIV-oxo). The myoglobin radical can attract an electron from 2,2' azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS). The resulting ABTS cation can be detected at 734 nm. Plasma antioxidants scavenge the metmyoglobin radicals and thus prevent the development of the ABTS radical, thereby reducing the blank absorbance. The antioxidant Trolox (Hoffman-La Roche) was used as calibrator, and a standard curve was constructed daily. The imprecision error of the method was evaluated by analyzing daily a plasma pool, which was always <5%.
High-Resolution B-Mode Ultrasound
Biosound 2000 II s.a. (Biosound Inc) was used to examine the extracranial carotid arteries bilaterally. This system, equipped with an 8-MHz transducer with pulsed-wave Doppler and spectrum analysis capabilities, provides high-resolution ultrasonic images with 0.3-mm axial resolution and 256 degrees of gray scale. The ultrasound imaging examination was performed by an experienced, certified sonographer (G.C.) following a standardized protocol developed by the Division of Vascular Ultrasound Research at Wake Forest University, School of Medicine, Winston-Salem, NC. The aims of the protocol were to define intra-arterial carotid artery anatomic references (ie, crest at the origin of the bifurcation and the arch of the flow divider) and specific ultrasonic interfaces on both the near and far walls to provide valid and reliable measurements of IMT at the level of 3 standardized segments: the distal 1.0 cm of the common carotid artery, the carotid bifurcation, and the proximal 1.0 cm of the internal carotid artery (Figure 1). Because of the high proportion of internal carotid arteries that could not be adequately visualized, the analyses were made on the bifurcation and common carotid arteries, where >99% of sites were visualized. Atherosclerotic plaques were defined as localized echogenic structures encroaching into the vessel lumen with an IMT >1.2 mm. The cutoff point of 1.2 mm for the IMT was chosen because it has been previously used in randomized clinical trials11,29 and also corresponds to the 90th percentile of the mean IMT, across common carotid artery and carotid bifurcation (near and far walls, bilaterally), in a random sample of Neapolitan adult women (n=170). The sonographer identified carotid plaques on the near and far walls of the common carotid arteries and carotid bifurcations on both sides. All measurements of IMT were made by the sonographer at the time of examination by using the machine electronic caliper. In our vascular laboratory, which has participated in interventional clinical trials using ultrasound, the previously reported within-subject coefficient of variation for IMT is <6%.30
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Statistical Analyses
Descriptive analyses, including mean, SD, and quartile cutoff points, are reported for all continuous variables. ANCOVA was used to obtain age-adjusted means for physical and biochemical variables and to compare groups with and without plaques at different sites. Most variables were divided into quartiles on the basis of the distribution of individual factors in the sample. Odds ratio calculations were based on the comparison of quartile 4 versus quartiles 1 to 3; they were determined by logistic regression, and 95% CIs were computed from the standard error of the regression coefficient, after adjustment for age. The choice of such a comparison was made to reduce small number problems. All analyses were performed with the SPSS for Windows 95 (release 8.0) statistical package for personal computers.
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Results |
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Physical and biochemical characteristics of the study participants are shown in Table 2. The majority (74%) were postmenopausal, and more than half of the women were current (44%) or past (18%) smokers.
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Prevalence of Carotid Artery Plaques by Site and Age
Atherosclerotic plaques (IMT >1.2 mm) were detected at more than one third of visualized sites, with a slight preponderance of lesions at the bifurcation. There were 105 women with no plaques at either site. The other 205 had common carotid artery or bifurcation plaques: 77 had plaques at the bifurcation, 37 had plaques at the level of the common carotid artery, and 91 had plaques at both sites.
There was a definite influence of age on the presence of plaques at bifurcations and at the common carotid arteries (Figure 2). Before age 50 years, the prevalence of lesions was 27% in the bifurcations and 19% in the common carotid arteries. A pronounced increase was present in the decade 50 to 59 years and after age 60 years: 74% of women had plaques in the bifurcations, and 59% had lesions in the common carotid arteries. Because of the influence of age on plaque prevalence and on several risk factors, age was considered a main confounder. All further comparisons were therefore performed after adjustment for age.
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Association of Carotid Plaques With Traditional Risk Factors
Mean age and LDL cholesterol were significantly higher in women with plaques at the carotid bifurcation than in those without plaques (57 versus 52 years; 4.3 versus 3.8 mmol/L; P<0.01), whereas no differences were detected for other traditional risk factors (Table 3). Women with common carotid artery plaques had higher BMI (29 versus 27 kg/m2; P<0.01), systolic blood pressure (143 versus 138 mm Hg; P<0.05), and pulse pressure (60 versus 55 mm Hg; P<0.01) than women without plaques at this arterial site (Table 3). Odds ratios for atherosclerotic plaques in relation to quartiles of cardiovascular risk factors (quartile 4 compared with quartiles 1 to 3) are reported in Table 4. LDL cholesterol in the upper quartile was associated with an increased risk of plaques at the bifurcation (odds ratio, 1.85; 95% CI, 1.04 to 3.27). BMI (odds ratio, 1.92; 95% CI, 1.11 to 3.33), and systolic blood pressure (odds ratio, 1.95; 95% CI, 1.12 to 3.41) were also associated with common carotid artery plaques. Smoking was significantly associated with plaques at the bifurcation (odds ratio, 2.02; 95% CI, 1.15 to 3.55; P<0.02) but not with plaques at the common carotid artery (odds ratio, 0.66; 95% CI, 0.38 to 1.14).
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Association of Carotid Plaques With Oxidation Markers
Lipid peroxidation markers, evaluated by TBARS measurement, were slightly higher in women with plaques at the carotid bifurcation (0.49 versus 0.44 µmol/L; P<0.05), whereas the presence of plaque in the common carotid artery was associated with higher titers of antibodies against oxidized LDL (402 versus 276 mU/mL in women without plaques; P<0.01) (Table 3).
A multivariate regression analysis (Table 5) showed that antibodies against oxidized LDL were associated with common carotid artery plaques, independently of age and level of conventional risk factors (LDL cholesterol, BMI, cigarette smoking, systolic blood pressure), with odds ratio of 2.72 (95% CI, 1.46 to 5.07; P=0.002).
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Lipid peroxides were positively associated (Table 5) with plaques at the bifurcation (odds ratio, 1.90; 95% CI, 1.04 to 3.47; P=0.04) and not at the common carotid artery, independently of age, LDL cholesterol concentrations, BMI, smoking habit, and systolic blood pressure.
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Discussion |
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TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
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Our data demonstrate that traditional and nontraditional cardiovascular risk factors are associated with site-specific carotid artery plaques in clinically healthy, middle-aged women living in the Mediterranean area.
In the present study the prevalence of early arterial abnormalities (66%) was relatively high compared with those found in other female population-based surveys conducted in Italy4 and elsewhere.31,32 The diverse definition of early arterial lesions adopted in our study and different risk factor pattern account for the disparity in values. We used an ultrasonographic end point to establish the presence of early, asymptomatic atherosclerosis. This end point was a categorical variable (IMT >1.2 mm) as measured by a sonographer (the same for all examinations) blind to the risk factor pattern of the women under study. The high prevalence of carotid plaques in our cohort is to some extent related to a relatively unfavorable risk profile of the participants in the study in regard to LDL cholesterol, BMI, and smoking. This may be partly explained by the fact that most of them were postmenopausal and partly by the lifestyle features that characterize the female population of the Neapolitan area at the present time. The dietary pattern, inspired by the Mediterranean tradition, has changed in the last decades in terms of calories and increase in dietary fat of animal origin. Together with sedentary habits (very frequent among women), this may explain the high prevalence of overweight and obese women and the high LDL cholesterol, which is especially increased after menopause. The concomitant increase in prevalence of smoking, which is the highest in Europe,33 places the Neapolitan population at high risk. A recent analysis of current and estimated future incidence and mortality data for cardiovascular disease in Italy has reported a historical trend that places the women in southern Italy (particularly those in the urban areas) at higher risk of cardiovascular events than other Italian women.34
The standardized protocol that we used to examine the anatomic segments under study allowed us to differentiate lesions within the common carotid artery and carotid bifurcation. The Atherosclerosis Risk in Communities (ARIC) Study acknowledged that the common carotid artery, carotid bifurcation, and internal carotid artery had different mean thicknesses, but no other site-specific features were identified.2 The Cardiovascular Health Study (CHS) discriminated between the common carotid artery and the internal carotid artery but did not establish criteria for identification of the bifurcation.7 We found that moderate elevations of LDL cholesterol and cigarette smoking were associated with plaques in the carotid bifurcation, while higher systolic blood pressure and BMI were associated with common carotid artery plaques. Furthermore, an association was demonstrated between concentration of lipid peroxidation products and site-specific plaques at the carotid bifurcation but not at the common carotid artery. This association was independent of age and traditional risk factors for coronary heart disease. We also demonstrated a strong and independent association of high titers of antibodies against oxidized LDL and plaques in the common carotid artery but not in the bifurcation. The association of oxidative markers with early carotid artery lesions in asymptomatic women is in agreement with the concept of involvement of oxidative processes in the early phases of atherogenesis.18
Two ultrasound studies introduced the idea of site-specific lesions, variably associated with different cardiovascular risk factors. Tell et al35 used a score system for presenting ultrasound results in a pooled population of men and women. Their results do not demonstrate a clear difference between bifurcation and common carotid artery with regard to the association with cigarette smoking and hypertension (however, their multivariate analysis did not include LDL cholesterol). Espeland et al36 evaluated IMT in men and women, with and without clinical evidence of coronary heart disease. In the subgroup without coronary heart disease (which is to some extent comparable to our clinically healthy women), they found an association of cigarette smoking and plaques at bifurcation and not at common carotid artery; their finding is in agreement with our results. However, they did not find the other associations with traditional cardiovascular risk factors (blood pressure, LDL cholesterol) found in our study; the smaller number of individuals examined and the mixture of men and women might explain this discrepancy.
The association of traditional risk factors and oxidation markers with early lesions in carotid segments that differ in geometry, shear stress, extracellular matrix structure thickness, and cell composition37 suggests that different mechanisms govern lesion development. LDL concentrations and cigarette smoking may contribute to early atherosclerotic structural changes in the bifurcation segment, which contains more macrophages37 than do contiguous segments and seems more susceptible to earlier LDL oxidation and lipid accumulation. High levels of lipid peroxidation products might be a marker of this process. The common carotid artery is primarily spared from atherosclerosis (although involved in medial hyperplasia due to hypertension). Consequently, plaques in this area are likely to reflect atherosclerotic progression marked by high titers of oxidized LDL antibodies. In this respect, we have found that overweight, high blood pressure, and low HDL cholesterol (3 features of the so-called metabolic syndrome) are all associated with common carotid artery plaques (with no relationship to bifurcation plaques), suggesting some shared mechanism of arterial damage.
This study, in agreement with others,35,36 suggests that caution should be exercised in extrapolating findings obtained in one arterial segment to others, even though they may be contiguous segments. The site specificity of arterial lesions also helps to explain the discrepancies among ultrasound studies using different arterial segment definition or lacking segment specification.
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Acknowledgments |
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This study was supported by funds from the Consiglio Nazionale delle Ricerche "Progetto finalizzato Biotecnologie," Rome, Italy; PRIN 1997, Ministero dell’Università e della Ricerca scientifica e tecnologica; and Regione Campania "Fondi ricerca sanitaria finalizzata." The Progetto Atena was supported by funds from the Consiglio Nazionale delle Ricerche "Progetto finalizzato / SUPPLEMENT"
Received March 20, 2001; revision received May 28, 2001; accepted June 14, 2001.
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References |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
1. Fuster V, Gotto AM, Libby P, Mc Gill HC. 27th Bethesda Conference: matching the intensity of risk factor management with the hazard of coronary disease events. Task Force 1: pathogenesis of coronary disease: the biologic role of risk factors. J Am Coll Cardiol. 1996; 27: 964–1047.[Medline] [Order article via Infotrieve]
2.
Heiss G, Sharret AR, Barnes R, Chambless LE, Szklo M, Alzola C, and the ARIC Investigators. Carotid atherosclerosis measured by B-mode ultrasound in populations: association with cardiovascular risk factors in the ARIC Study. Am J Epidemiol. 1991; 134: 250–256.
3.
Bots MML, Breslau PJ, Briet E, de Bruyn AM, van Vliet HHDM, van der Ouweland FA, de Jong PTVM, Grobbee DE. Cardiovascular determinants of carotid artery disease: the Rotterdam Elderly Study. Hypertension. 1992; 19: 717–720.
4.
Prati P, Vanuzzo D, Casaroli M, Di Chiara A, De Biasi F, Feruglio GA, Touboul PJ. Prevalence and determinants of carotid atherosclerosis in a general population. Stroke. 1992; 23: 1705–1711.
5.
Bots ML, Hoes AW, Koudstaal PJ, Hofman A, Grobbee DE. Common carotid intima-media thickness and risk of stroke and myocardial infarction: the Rotterdam Study. Circulation. 1997; 96: 1432–1437.
6.
Chambless LE, Heiss G, Folsom A, Rosamond W, Szklo M, Sharrett AR, Clegg LX. Association of coronary heart disease incidence with carotid arterial wall thickness and major risk factors: the Atherosclerosis Risk in Communities (ARIC) Study, 1987–93. Am J Epidemiol. 1997; 146: 483–494.
7.
O’Leary DH, Polak JF, Kronmal RA, Manolo TA, Burke GL, Wolfson SK, for the Cardiovascular Health Study Collaborative Research Group. Carotid artery intima and media thickness as a risk factor for myocardial infarction and stroke in older adults. N Engl J Med. 1999; 340: 14–22.
8. Salonen R, Salonen JT. Progression of carotid atherosclerosis and its determinants: a population-based ultrasonography study. Atherosclerosis. 1990; 81: 33–40.[Medline] [Order article via Infotrieve]
9. Bond MG, Strickland HL, Wilmoth SK, Safrit A, Phillips R, Szostak L, for the MIDAS Research Group. Interventional trials using noninvasive ultrasound end-points: the multicenter Isradipine/Diuretic Atherosclerosis Study. J Cardiovasc Pharmacol. 1990; 15 (suppl 1): S30–S33.
10.
Furberg CD, Adams HP Jr, Applegate WB, Byington RP, Espeland MA, Hartwell T, Hunninghake DB, Lefkowitz DS, Probstfield J, Riley WA, Young B. Effect of lovastatin on early carotid atherosclerosis and cardiovascular events. Circulation. 1994; 90: 1679–1687.
11. Mercuri M, Bond MG, Sirtori CR, Veglia F, Crepaldi G, Feruglio FS, Descovich GC, Ricci G, Rubba P, Mancini M, Gallus G, Bianchi G, D’Alo’ G, Ventura A. Pravastatin reduces intima-media thickness progression in an asymptomatic hypercholesterolemic Mediterranean population: the Carotid Italian Ultrasound Study. Am J Med. 1996; 101: 627–634.[Medline] [Order article via Infotrieve]
12.
MacMahon S, Sharpe N, Gamble G, Hart H, Scott J, Simes J, White H, for the LIPID Trial Research Group. Effects of lowering average of below-average cholesterol levels on the progression of carotid atherosclerosis: results of the LIPID atherosclerosis substudy. Circulation. 1998; 97: 1784–1790.
13.
Pignoli P, Tremoli E, Poli A, Oreste P, Paoletti R. Intimal plus medial thickness of the arterial wall: a direct measurement with ultrasound imaging. Circulation. 1986; 74: 1399–1406.
14. Salonen JT, Yla-Herttuala S, Yamamoto R, Butler S, Korpela H, Salonen R, Nyyssonen K, Palinski W, Witzum JL. Autoantibody against oxidised LDL and progression of carotid atherosclerosis. Lancet. 1992; 339: 883–887.[Medline] [Order article via Infotrieve]
15.
Maggi E, Chiesa R, Melissano G, Castellano R, Astore D, Grossi A, Finardi G, Bellomo G. LDL oxidation in patients with severe carotid atherosclerosis: a study of in vitro and in vivo oxidation markers. Arterioscler Thromb. 1994; 14: 1892–1899.
16.
Bergmark C, Wu R, de Faire U, Lefvert AK, Swedenborg J. Patients with early onset peripheral vascular disease have increased levels of autoantibodies against oxidized LDL. Arterioscler Thromb Vasc Biol. 1995; 15: 441–445.
17. van de Vijver LPL, Steyger G, van Poppel G, Boer JMA, Kruijssen DACM, Seidell JC, Princen HMG. Autoantibodies against MDA-LDL in subjects with severe and minor atherosclerosis and healthy population control. Atherosclerosis. 1996; 122: 245–253.[Medline] [Order article via Infotrieve]
18.
Diaz MN, Frei B, Vita JA, Keaney JF. Antioxidants and atherosclerotic heart disease. N Engl J Med. 1997; 337: 408–416.
19. Malgren R, Warlow C, Bamford J, Sandercock P. Geographical and secular trends in stroke incidence. Lancet. 1987; 1: 1196–1200.
20. Panico S, Dello Iacovo R, Celentano E, Galasso R, Muti P, Salvatore M, Mancini M. Progetto Atena, a study on the etiology of major chronic diseases in women: design, rationale and objectives. Eur J Epidemiol. 1992; 8: 601–608.[Medline] [Order article via Infotrieve]
21.
The ARIC Investigators. The Atherosclerosis Risk in Communities (ARIC) Study: design and objectives. Am J Epidemiol. 1989; 129: 687–702.
22. Siedel J, Schlumberger H, Klose S, Ziegenhorn J, Wahlefeld AW. Improved reagent for enzymatic determination of serum cholesterol. J Clin Chem Biochem. 1981; 19: 838–839.
23. Wahlefeld AW. Triglyceride determination after enzymatic hydrolysis.In: Bergmeyer HU, ed. Methods of Enzymatic Analysis.. Vol 4. 2nd ed. New York, NY: Academic Press; 1974: 1831.
24.
Lopes-Virella MF, Stone P, Ellis S, Colwell JA. Cholesterol determination in high-density lipoproteins separated by three different methods. Clin Chem. 1977; 23: 882–884.
25. Jentzsch AM, Bachmann H, Furst P, Biesalski HK. Improved analysis of malondialdehyde in human body fluids. Free Radic Biol Med. 1996; 20: 251–256.[Medline] [Order article via Infotrieve]
26. Valenzuela A. The biological significance of malondialdehyde in the assessment of tissue oxidative stress. Life Sci. 1990; 48: 301–309.
27. Miller NJ, Rice-Evans C, Davies MJ, Gopinathan V, Milner A. A novel method for measuring antioxidant status in premature neonates. Clin Sci. 1993; 84: 407–412.[Medline] [Order article via Infotrieve]
28. Miller NJ, Rice-Evans C, Gopinathan V, Davies MJ, Milner A. A new method for estimating plasma antioxidant activity and its application to the investigation of antioxidant status in premature neonate.In: Free Radicals and Antioxidants in Nutrition. London, UK: Richelieu Press; 1993.
29. Tang R, Hennig M, Thomasson B, Sherz R, Ravinetto R, Catalini R, Rubba P, Zanchetti A, Bond MG. Baseline reproducibility of B-mode ultrasonic measurement of carotid artery intima-media thickness: the European Lacidipine Study on Atherosclerosis (ELSA). J Hypertens. 2000; 18: 197–201.[Medline] [Order article via Infotrieve]
30.
Pauciullo P, Iannuzzi A, Sartorio R, Irace C, Covetti G, Di Costanzo A, Rubba P. Increased intima-media thickness of the common carotid artery in hypercholesterolemic children. Arterioscler Thromb. 1994; 14: 1075–1079.
31.
Bonithon-Koop C, Scarabin PY, Taquet A, Touboul PJ, Almejac A, Guize L. Risk factors for early carotid atherosclerosis in middle-aged French women. Arterioscler Thromb. 1991; 11: 966–972.
32.
Lassila HC, Sutton Tyrrel K, Matthews KA, Wolfson SK, Kuller LH. Prevalence and determinants of carotid atherosclerosis in postmenopausal women. Stroke. 1997; 28: 513–517.
33.
Beer-Borst S, Morabia A, Hercberg S, Vitek O, Bernstein MS, Galan P, Galasso R, Giampaoli S, Houterman S, McCrum E, Panico S, Pannozzo F, Preziosi P, Ribas L, Serra-Majem L, Verschuren WM, Yarnell J, Northridge ME. Obesity and other health determinants across Europe: the EURALIM project. J Epidemiol Community Health. 2000; 54: 424–430.
34. Giampaoli S, Palmieri L, Pilotto L, Vanuzzo D. Incidence and prevalence of ischemic heart disease in Italy: estimates from the MIAMOD method. Ital Heart J. 2001; 2: 349–355.[Medline] [Order article via Infotrieve]
35. Tell GS, Howard G, McKinney W. Risk factors for site specific extracranial carotid artery plaque distribution as measured by B-mode ultrasound. J Clin Epidemiol. 1989; 42: 551–559.[Medline] [Order article via Infotrieve]
36.
Espeland M, Tang R, Terry JG, Davis DH, Mercuri M, Crouse JR III. Associations of risk factors with segment-specific intimal-medial thickness of the extracranial carotid artery. Stroke. 1999; 30: 1047–1055.
37.
Stary HC, Blankenhorn DH, Chandler AB, Glagov S, Insull W, Richardson M, Rosenfeld ME, Schaffer SA, Schwartz CJ, Wagner WD, Wissler RW. A definition of the intima of human arteries and of its atherosclerotic-prone regions. Arterioscler Thromb. 1992; 12: 120–134.
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 A. Iannuzzi, M. De Michele, S. Panico, E. Celentano, R. Tang, M. G. Bond, L. Sacchetti, F. Zarrilli, R. Galasso, M. Mercuri, et al. Radical-Trapping Activity, Blood Pressure, and Carotid Enlargement in Women Hypertension, February 1, 2003; 41(2): 289 - 296. [Abstract] [Full Text] [PDF]
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M. De Michele, S. Panico, A. Iannuzzi, E. Celentano, A. V. Ciardullo, R. Galasso, L. Sacchetti, F. Zarrilli, M. G. Bond, and P. Rubba Association of Obesity and Central Fat Distribution With Carotid Artery Wall Thickening in Middle-Aged Women Stroke, December 1, 2002; 33(12): 2923 - 2928. [Abstract] [Full Text] [PDF]
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