Article Figures & Data
Figures
- Fig 1.
High-resolution B-mode sonography of the carotid artery demonstrating the far wall IMT. A, A characteristic longitudinal 2D sonogram of the CCA, BIF, and proximal ICA. The rectangle marks the arterial wall segment of the CCA, which is detailed and magnified in B and C. B, The dashed line above the blood/intima borderline spans the distance over which the IMT is to be measured. C, The gray value−based edge detection software delineates both blood/intimal and medial/adventitial borderline.15
Tables
Black Individuals (n = 306) White Individuals (n = 281) P Valueb Age (yr) 60.6 (9.3) 61.1 (8.0) .825 Sex (men) 189 (61.8) 223 (79.4) .000 Systolic blood pressure (mm Hg) 142.0 (17.8) 139.0 (19.4) .011 Diastolic blood pressure (mm Hg) 85.3 (10.1) 83.7 (10.7) .030 Antihypertensive therapy 129 (42.7) 46 (16.4) .000 Hypertension 218 (71.2) 161 (57.3) .000 Smoking: pack-years 6.7 (13.9) 21.9 (29.9) .000 Current smoker 60 (19.6) 77 (27.4) .000 Ex-smoker 69 (22.5) 106 (37.7) Never 177 (57.8) 98 (34.9) Diabetes mellitus 62 (20.3) 18 (6.4) .000 Myocardial infarct 7 (2.3) 16 (5.7) .114 Serum cholesterol (mmol/L) 5.1 (1.1) 5.5 (1.1) .000 BMI (kg/m2) 28.2 (5.8) 27.0 (5.3) .067 Socioeconomic status .000 I 11 (3.6) 12 (4.3) II 28 (9.2) 76 (27) IIIa 53 (17.3) 51 (18.1) IIIb 92 (30.1) 67 (23.8) IV 79 (25.8) 40 (14.2) V 43 (14.1) 35 (12.5) -
a Values are No. (%) or mean (± SD).
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b Age- and sex-adjusted.
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- Table 2:
Age and sex-adjusted carotid IMT and diameter measurements and prevalence of carotid plaque in the 2 ethnic groupsa
Black Individuals White Individuals P Value Mean CCA-IMT (mm) LCCA 0.817 ± 0.009 0.771± 0.010 .001 RCCA 0.790 ± 0.008 0.729 ± 0.009 .000 Mean CCA 0.804 ± 0.008 0.750 ± 0.008 .000 Maximum CCA-IMT (mm) LCCA 0.970 ± 0.022 0.810 ± 0.021 .000 RCCA 0.899 ± 0.027 0.741 ± 0.015 .000 Mean CCA 0.940 ± 0.020 0.770 ± 0.015 .000 Maximum BIF/ICA-IMT (mm) LBIF 0.778 ± 0.020 0.685 ± 0.010 .000 RBIF 0.760 ± 0.020 0.657 ± 0.010 .000 Mean BIF 0.780 ± 0.020 0.676 ± 0.010 .000 Mean ICA 0.659 ± 0.010 0.574 ± 0.010 .000 CCA diameter (cm) LCCA 0.592 ± 0.005 0.618 ± 0.005 .000 RCCA 0.599 ± 0.004 0.624 ± 0.005 .000 Mean CCA 0.596 ± 0.004 0.621 ± 0.005 .000 Carotid plaque (No.) (%) 17 (5.6) 34 (12.1) .004 -
a Values are mean ± SE. IMT results are from semiautomated analysis of an arterial segment giving a value of mean CCA-IMT and from the manual measurement of the single maximum value (maximum IMT) for CCA, BIF, and ICA. CCA diameters are from manual measurements taken during systole.
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- Table 3:
Relationship between cardiovascular risk factors and mean CCA-IMT in the 2 ethnic groups from univariate and multivariate regression analysis
Risk Factor Black Individuals White Individuals Univariate Multivariate (R2 = 0.20)a Univariate Multivariate (R2 = 0.23)a B P B P B P B P Age 0.006 .000b 0.006 .000b 0.006 .000b 0.005 .000b Male sex 0.052 .003b 0.037 .040b 0.021 .287 −0.034 .085 Hypertension 0.052 .006b 0.008 .674 0.065 .000 0.023 .168 Diabetes 0.082 .000b 0.043 .038b 0.118 .000b 0.126 .000b BMI 0.001 .338 0.003 .096 0.003 .046b 0.003 .103 Cholesterol −0.003 .731 0.002 .802 0.006 .466 0.006 .430 Smoking: pack-years 0.000 .736 0.000 .435 0.001 .005b 0.000 .068 Low social class −0.020 .436 −0.047 .053 0.032 .071 0.015 .394 -
a R2 = proportion of variance in IMT explained by conventional risk factors.
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b P = 0.05.
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Risk Factor Black Individuals: Explained Variance (R2) White Individuals: Explained Variance (R2) Mean CCA-IMT Mean Max CCA-IMT Mean CCA-IMT Mean Max CCA-IMT All 20% 11% 23% 20% Age 15.6% 7.5% 12% 8.4% Male sex – – – 6.6% Diabetes 1.4% – 5.1% 1.5% Smoking: pack-years – – 2.0% – Hypertension – – 1.5% – Low social class – – – 1.7% High social class 1.3% – – – -
Note:— – indicates no explained variance.
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