Table 3 Percentage of men with plaques, maximal height and longitudinal area of plaque, of men with plaque height and areas above specified values
and ultrasound score UAS in the bifurcational area of the common carotid CCA and femoral CFA arteries, means 9 SEM Linko¨ping n = 100
P Vilnius n = 100
CCA 28
53 B
0.001
b
Of men with plaque 0.48 9 0.1
height mm 0.001
a
0.83 9 0.1 20
32 0.053
b
of men with plaque height\1 mm 9
0.489
b
of men with plaque height\2 mm 12
3.29 9 0.88 5.84 9 1.2
0.001
a
area mm
2
30 of men with plaque area \5 mm
2
17 0.030
b
10 of men with plaque area \15 mm
2
5 0.179
b
CFA Of men with plaque
73 37
B 0.001
b
0.77 9 0.1 1.50 9 0.1
B 0.001
a
height mm 32
of men with plaque height\1 mm B
0.001
b
65 16
33 0.005
b
of men with plaque height\2 mm area mm
2
15.8 9 1.8 9.02 9 1.7
B 0.001
a
29 55
B 0.001
b
of men with plaque area\8 mm
2
18 of men with plaque area\22 mm
2
0.115
b
25 50
85 B
0.001
b
with plaque in one or both arteries 1.14 9 0.20
Carotid UAS points 0.002
1.94 9 0.22 1.70 9 0.24
3.42 9 0.24 B
0.001 Femoral UAS points
2.84 9 0.35 Total UAS points
B 0.001
5.35 9 0.35
a
Mann-Whitneys test.
b
Chi-square test.
2
.
3
. Biochemical analysis Samples for plasma lipoprotein analysis were drawn
in the fasting state. LDL was determined according to the Friedewald formula [21]. The susceptibility of LDL
to oxidation was measured as described by Kleinfeld et al. [22]. Plasma concentrations of the lipophilic antioxi-
dant vitamins a- and g-tocopherol and a- and b- carotene were determined by reverse phase high
performance liquid chromatography [23]. Concentra- tions of a- and g-tocopherol were expressed per total
triglyceride plus total cholesterol concentrations.
2
.
4
. Statistical methods The distribution of measures of intima media and of
area and height of plaques were skewed, and therefore the Mann – Whitney’s test two-tailed was used to test
differences between the two groups. For continuous, normally distributed data Student’s t-test, and for di-
chotomous variables chi-square test were used. Linear multiple regression models were used to analyse the
dependence of IMT
mean
, IMT
max
, UAS, and stiffness on SBP, smoking and LDL-cholesterol, a- and g- toco-
pherol, a- and b-carotene, lycopene, and lag phase for oxidation of LDL. In these models, interactions be-
tween city and the independent variables were tested and found not to be significant. Therefore, we present
results from regression models for pooled data. Only adjusted explanatory values r
2
are presented. Partial correlation analyses, adjusted for city, were performed
to analyse the associations between the independent variables and for relationships between the different
ultrasound measures used. A P-value of 0.01 or less was regarded as significant.
3. Results
Characteristics of the groups are presented in Table 1. Mean SBP and BMI were higher in Vilnius men,
Fig. 1. Frequency distribution of total ultrasound atherosclerotic score among Vilnius and Linko¨ping men. For definition of the UAS
score see text.
Table 4 Stiffness and wall motion in the common carotid artery CCA,
systolic blood pressure SBP, diastolic blood pressure DBP, pulse pressure and ankle-brachial index, means 9 SEM
Linko¨ping Vilnius
P n = 100
n = 100 CCA stiffness b
3.6 9 0.2 2.8 9 0.1
B 0.001
0.52 9 0.02 0.66 9 0.03
B 0.001
CCA wall motion mm
129 9 2 SBP mmHg
B 0.001
139 9 2 85 9 1
92 9 1 B
0.001 DBP mmHg
Pulse pressure 48 9 1
44 9 1 0.077
mmHg 1.16 9 0.01
1.18 9 0.01 Ankle-brachial
0.327 index
tively, but pulse pressure did not differ. Also, ankle- brachial index i.e. ankle systolic pressurearm systolic
pressure did not differ between the cities Table 4. The correlation analysis between the independent
variables included in the linear regression models showed, after adjustment for city, significant and high
correlations range 0.75 – 0.77 between SBP and DBP, and between a-carotene and b-carotene. Moderate, and
significant correlations range 0.21 – 0.37 were found for both a-and b-carotene to lycopene, LDL-cholesterol
and to a-tocopherol. Likewise, moderate correlations were found between a-tocopherol and lag phase, and
negative between smoking and a-carotene.
The linear regression model for total UAS is pre- sented in Table 5. In a multiple stepwise model on the
pooled patient sample from both cities, in which city was first entered into the model, smoking, high SBP,
high LDL-cholesterol, and low b-carotene significantly contributed to high total UAS r
2
= 0.32. In models
for the two cities taken separately, the explanatory value was higher for Linko¨ping men than for Vilnius
men r
2
= 0.37 and 0.14, respectively. In the Linko¨ping
group, smoking, high LDL cholesterol, low b-carotene, and high a-tocopherol significantly related to a high
total UAS; in Vilnius this was the case for smoking, high SBP, and low lycopene. When the multiple step-
wise model was used for the carotid UAS separately, on the pooled patient sample, in which city was first en-
tered, high SBP, DBP, smoking and high a-tocopherol came out significantly r
2
= 0.18. For femoral UAS
smoking, high LDL, and low b-carotene significantly contributed r
2
= 0.29. Linear regression models with
IMT as the dependent variable and controlled for city, showed low explanatory values carotid IMT; r
2
= 0.08
and femoral IMT; r
2
= 0.15. SBP contributed signifi-
cantly to high carotid IMT; smoking and LDL-choles- terol to high femoral IMT, the results being the same
for IMT
mean
and IMT
max
values. In the model with stiffness as dependent variable, high SBP significantly
contributed to high carotid stiffness r
2
= 0.18. Neither
BMI, low physical activity, a-carotene, g-tocopherol nor LDL lag phase contributed significantly to amount
of atherosclerosis in any of the models tested. total and LDL cholesterol were higher in Linko¨ping
men while smoking habits, alcohol intake and diabetes prevalence were similar in the two cities. More Vilnius
men reported low physical activity at leisure time, but there was no difference in the proportion of men with
low physical activity at work time. Serum levels of the lipid soluble antioxidant vitamins b-carotene, lycopene
and g-tocopherol were lower and mean LDL lag phase shorter in Vilnius than in Linko¨ping men.
Measures of lumen diameter and IM-complex were obtained in all but one individual with an extensive
femoral plaque. Results are presented in Table 2. In the CFA, a larger proportion of Vilnius men had IMT
max
above 1 mm P = 0.005. In CCA no significant differ- ences for these measures were found. Mean lumen
diameter did not differ in either artery. As shown in Table 3, plaques were more common in Vilnius men,
both in CCA and in CFA P B 0.001 for both. Also, more Vilnius men had, in both CCA and CFA, larger
plaques, both measured as height and area P B 0.001 for all. Accordingly, their CCA, CFA and total UAS
were higher Fig. 1. Flow velocity was normal in all investigated arteries. Wall movement in CCA was lower
and calculated stiffness in CCA higher in Vilnius men P for both B 0.001. Both SBP and DBP, measured
just after registration of vessel wall motility, were higher in Vilnius men P = 0.002 and P B 0.001, respec-
Table 5 Multiple linear regression analysis with total ultrasound atherosclerosis score as dependent variable, pooled group, n = 200
a
P Standard error of Beta
Partial regression coefficient Country
B 0.001
0.499 2.178
Tobacco gday B
0.001 0.148
0.028 0.030
0.012 0.013
SBP mm Hg LDL cholesterol mmoll
0.001 0.920
0.264 −
0.003 0.004
0.001 b-carotene nmoll
a
Adjusted r
2
= 0.32
4. Discussion
