pared to IMT, even stronger relations to acute myocar- dial infarction [9]. Also, an increased arterial stiffness
has been suggested to be an indicator of early artery wall disease [16].
The aim of this part of the LiVicordia study was to compare the amount of atherosclerosis in the two pop-
ulations by estimating IMT, number and size of atherosclerotic plaques, and wall stiffness. In addition
we wanted to relate the findings to traditional and possible new risk factors for CHD.
2. Methods
2
.
1
. Study design LiVicordia is a cross-sectional study conducted from
October l993 to June l994. A list of randomly selected men, born between July 1, l943 and June 30, l944 was
obtained from the census register in each of the cities of Vilnius 600 000 inhabitants and Linko¨ping 130 000
inhabitants. One hundred men in each city underwent an ultrasound investigation of the right carotid and
femoral arteries. In Linko¨ping the response rate was 82 and in Vilnius 74. The only exclusions were two
men with serious cancer. The ultrasound examinations were performed between December 1993 and April
1994 in Linko¨ping and during 2 weeks in May 1994 in Vilnius. In Linko¨ping the investigations took place
between 10:00 and 12:00 h and in Vilnius between 08:00 and 16:00 h. In addition, anthropometric measures,
blood pressure, and blood samples were taken. Details of the procedures and methods for these investigations
have been given previously [7]. The study was approved by the Ethical Committee of the Faculty of Health
Sciences in Linko¨ping and all participants gave written informed consent.
2
.
2
. Ultrasound measurements and e6aluation The same Acuson XP10 ultrasound scanner Acuson,
Mountain View, CA with a 5 MHz linear 2D scanhead was used in both cities, and the same four experienced
persons collected primary data. The investigations were standardised according to present recommendations
[17,18]. The carotid vessels were investigated for the presence of stenosis with spectral doppler at 60°
doppler angle, and if a peak systolic velocity of more
Table 1 Anthropometric, lifestyle and biochemical data in Vilnius and Linko¨ping men
a
Vilnius n = 100 Linko¨ping n = 100
P 82.0 9 1.2
Body mass kg 80.4 9 1.2
0.334 Height cm
0.001 178 9 1
175 9 1 26.8 9 0.3
BMI kgm
2
25.4 9 0.4 0.005
17 BMI\30
8 0.054
b
0.92 9 0.01 Waisthip ratio
0.91 9 0.01 0.246
139 9 2 132 9 2
SBP mm Hg 0.013
87 9 1 86 9 1
DBP mm Hg 0.444
Not calculated 2
Diabetes 1
0.112
b
36 Current smokers
27 Tobacco gday
0.628 4.92 9 0.97
5.56 9 0.88 42
0.443
b
40 Never smokers
0.723 94.6 9 16.2
Alcohol intake gweek 87.8 9 10.2
Low physical activity During leisure time
40 18
B 0.001
b
0.476
b
42 During work time
41 35
Blue collar workers 25
0.082
b
Triglycerides mmoll 1.46 9 0.14
1.52 9 0.12 0.719
0.004 Total cholesterol mmoll
5.06 9 0.10 5.48 9 0.10
3.30 9 0.09 LDL cholesterol mmoll
3.67 9 0.10 0.003
HDL cholesterol mmoll 1.15 9 0.03
1.13 9 0.03 0.577
LDLHDL cholesterol 3.03 9 0.12
3.50 9 0.14 0.015
67.6 9 1.3 LDL lag phase min
79.5 9 1.3 B
0.001 0.715
81.6 9 5.6 85.2 9 8.0
a-Carotene nmoll 512 9 33
0.001 377 9 20
b-Carotene nmoll Lycopene nmoll
316 9 22 617 9 33
B 0.001
3.3 9 0.1 3.4 9 0.1
0.345 a-Tocopherol mmolmmol
c
0.25 9 0.01 0.46 9 0.02
g-Tocopherol mmolmmol
c
B 0.001
a
means 9 SEM, BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; HDL, high density lipoprotein; LDL, low density lipoprotein.
b
Chi-square test.
c
Values obtained for a- and g-tocopherol were divided by plasma concentrations of cholesterol+triglycerides.
Table 2 Lumen
diameter, mean
and maximal
intima-media thickness
IMT
mean
, IMT
max
in mm and of men with IMT
mean
and IMT
max
B 0.7 and\1 mm in the carotid and femoral arteries of
Vilnius and Linko¨ping men, means 9 SEM Linko¨ping
Vilnius P
n = 100 n = 100
6.61 9 0.07 Carotid lumen
6.46 9 0.06 0.117
diameter 0.73 9 0.02
Carotid IMT
mean
0.148
a
0.75 9 0.02 with IMT
mean
41 55
0.048
b
B 0.7 mm
with IMT
mean
4 6
0.516
b
\ 1 mm
0.89 9 0.02 Carotid IMT
max
0.929
a
0.90 9 0.03 with IMT
max
4 6
0.516
b
B 0.7 mm
13 with IMT
max
19 0.247
b
\ 1 mm
n = 99 n = 100
Femoral lumen 8.90 9 0.11
9.06 9 0.09 0.255
diameter 0.85 9 0.04
Femoral IMT
mean
0.005
a
0.91 9 0.04 with IMT
mean
22 37
0.020
b
B 0.7 mm
20 with IMT
mean
14 0.259
b
\ 1 mm
Femoral IMT
max
1.05 9 0.05 1.12 9 0.04
0.007
a
2 with IMT
max
4 0.683
c
B 0.7 mm
46 26
0.005
b
with IMT
max
\ 1 mm
a
Mann–Whitney’s U-test.
b
Chi-square test.
c
Fisher’s exact test.
an ankle cuff and an ultrasound Doppler probe on the posterior tibial artery.
Two researchers performed off-line evaluations of all data from both centres using a computerised analysing
system [19] permitting about 100 paired measurements at 10 mm. The mean of three different images of the
same segment was used in the calculations, resulting in about 300 paired measurements in each volunteer. Lu-
men diameter was defined as the mean distance between leading edges of the proximal and distal lumen-intima
interfaces and the IM-complex as the mean and maxi- mal distance between distal lumen-intima and media-
adventitia interfaces IMT
mean
, IMT
max
. In both CCA and CFA, lumen diameter, IMT
mean
, IMT
max
and wall movements systolic minus diastolic diameter, in CCA
only were measured in a 10 mm long section immedi- ately adjacent to the bifurcation. A plaque was defined
as a distinct area with an IMT more than 50 thicker than neighbouring sites, if the IM-complex was visible
in that projection. In the CCA, carotid bulb and CFA this was usually so, but in the carotid bifurcation small
echogenic plaques were often found in the lateral or anterior walls. These were also included and measured
but with less accuracy, as the IM-complex could not be exactly delineated. In some cases with large plaques in
the CFA no exact delineation could be made in the cranial direction, so the proximal limit of the plaque
was set where the external iliac artery ‘descends down’ into the bowel. Plaques were recorded both in the
longitudinal and in the transverse mode. Plaque size was evaluated by maximal height and area, only in a
longitudinal image. Delineation of plaque was con- ducted visually. Arterial stiffness in CCA was calcu-
lated as b = log systolicdiastolic arm BP divided by wall movement diastolic diameter [16,20].
All tapes were measured in random order with regard to city of origin. Reproducibility of double recordings
for the laboratory has been measured in patients with hyperlipidemia. The results are expressed as the per-
centage difference, i.e. the difference between highest and lowest value divided by lowest value × 100, and
were in CCA and CFA, respectively: lumen diameter 4 9 4 and 5 9 3, IMT
max
10 9 8 and 15 9 14, IMT
mean
8 9 8 and 14 9 10; plaque height 11 9 8 and 7 9 5, plaque area 13 9 10 and 13 9 12, and
stiffness 14 9 11 CCA only. An ultrasound atherosclerotic score UAS was cal-
culated from IMTmax andor the largest plaque in each of CCA and CFA as follows: IMT 5 1 mm and no
plaque was considered normal = 0 points; IMT B 1 – 2 mm or a plaque with a maximal height of 1 mm only
present in the carotid bifurcation = 2 points; a plaque with maximal height of \ 1 – 2 mm = 4 points; maximal
height \ 2 mm = 6 points; 50 stenosis = 8 points; and high grade stenosis \ 70 or occlusion = 10 points.
than 1.2 ms was found in conjunction with a plaque, a 50 – 75 stenosis was diagnosed. A peak systolic
velocity of 2.5 ms was used as a limit for high grade stenosis \ 70 according to the ECST criteria. In
the right CCA, lumen diameter and far wall intima- media IM complex were obtained for a distance of
10 mm immediately distal to the bulb, and recorded on videotape in end-diastole, triggered on the R-wave
of an ECG. In the presence of plaque, the IM-com- plex was obtained in an angle free from plaque. In
addition, wall movements of the cranial part of CCA were recorded in M-mode. The scanning was con-
cluded by a thorough visual search for plaques in the CCA, in the bifurcational area and in the visible parts
of the internal and external carotid arteries. The right common femoral artery CFA was examined in a
similar way, from a position immediately cranial of the inguinal ligament to about 5 cm down the superfi-
cial and profunda femoral arteries. Right arm systolic SBP and diastolic DBP blood pressure was mea-
sured by cuff and stethoscope, and right ankle SBP by
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
