CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 2, March 2012
AFRICA
81
CRP, cortisol and hypertension to the increased likelihood of
cardiovascular disease in both African and Caucasian women
from South Africa. This study is relevant in that it describes the
relationship between various cardiovascular risk markers and
hypertension in two ethnic groups, which, as far as we have
ascertained, have been neglected.
Hypertensive Caucasian women exhibited an increased central
cardiac activity, as demonstrated by the increased CO (Table 2,
Fig. 2). There was also a significant difference between normo-
tensive and hypertensive SBP and DBP values, respectively, for
Caucasian women (Table 2). These observations, in conjunction
with the decreased cortisol levels in the hypertensive group,
suggest increased sympathetic reactivity with an accompanying
hypocortisolism. This corresponds with recent studies,
4,10,18
where
it was found that hypocortisolism has in some cases been related
to hypertension.
Hypertensive African women, conversely, showed increased
vascular reactivity (Table 2, Fig. 1). Cw significantly decreased
in this group, with a corresponding significant increase in TPR.
Hypocortisolism was also exhibited in the hypertensive African
women (Table 2). This possibly suggests an over-stimulated
HPA axis, leading to hypertension in association with hypo-
cortisolism.
4,10,18
Urbanisation has previously been shown to be a psychosocial
stressor that contributes to increased cardiovascular reactivity
and hence, hypertensiveness.
1-6
Since the African women in this
study were urbanised, one could hypothesise that this could
be a possible explanation for these results.
16
Specifically, the
TABLE 3. SIGNIFICANTASSOCIATIONS BETWEEN CARDIOVASCULARANDANTHROPOMETRICVARIABLESAND
HIGH-SENSITIVITY LOG CRP IN NORMOTENSIVEAND HYPERTENSIVEAFRICANAND CAUCASIANWOMEN
African women
Caucasian women
Log CRP: normotensive
Log CRP: hypertensive
Log CRP: normotensive
Log CRP: hypertensive
r
p
r
p
r
p
r
p
WC (cm)
0.46
0.00
0.69
0.03
0.39
0.01
0.53
0.45
BMI (kg/m
2
)
0.37
0.02
0.80
0.00
0.43
0.00
0.52
0.48
CO (l/min)
0.28
0.18
0.66
0.04
0.29
0.15
0.52
0.47
SV (ml)
0.19
0.56
0.73
0.01
0.21
0.47
0.84
0.01
TPR (mmHg/s/ml)
0.28
0.17
0.74
0.01
0.31
0.09
0.59
0.33
Cw (ml/mmHg)
0.24
0.34
0.85
0.00
0.18
0.63
0.83
0.01
SBP (mmHg)
0.31
0.10
0.79
0.00
0.81
0.97
0.53
0.47
DBP (mmHg)
0.16
0.73
0.64
0.06
0.14
0.84
0.62
0.26
CRP, C-reactive protein; WC, waist circumference; BMI, body mass index; CO, cardiac output; SV, stroke volume; TPR, total peripheral resis-
tance; Cw, Windkessel compliance; SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation. All data were adjusted for
age, smoking and alcohol consumption and tested at a 95% confidence interval. Significant differences (
p
<
0.05) are highlighted in bold. Signifi-
cant differences (
p
≤
0.05) between variables in the groups are indicated with the same superscript letters.
TABLE 4. SIGNIFICANTASSOCIATIONS BETWEEN CARDIOVASCULARANDANTHROPOMETRICVARIABLESAND LOG
CORTISOL IN NORMOTENSIVEAND HYPERTENSIVEAFRICANAND CAUCASIANWOMEN
African women
Caucasian women
Log cortisol: normotensive Log cortisol: hypertensive Log cortisol: normotensive Log cortisol: hypertensive
r
p
r
p
r
p
r
p
WC (cm)
0.46
0.00
0.23
0.93
0.38
0.02
0.53
0.46
BMI (kg/m
2
)
0.35
0.04
0.28
0.84
0.41
0.00
0.52
0.48
TPR (mmHg/s/ml)
0.28
0.18
0.66
0.048
0.32
0.09
0.59
0.32
Cw (ml/mmHg)
0.23
0.36
0.82
0.00
0.18
0.66
0.81
0.02
SBP (mmHg)
0.24
0.36
0.73
0.01
0.16
0.72
0.64
0.22
DBP (mmHg)
0.14
0.84
0.62
0.09
0.18
0.65
0.80
0.03
CRP, C-reactive protein; WC, waist circumference; BMI, body mass index; CO, cardiac output; SV, stroke volume; TPR, total peripheral resis-
tance; Cw, Windkessel compliance; SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation. All data were adjusted for
age, smoking and alcohol consumption and tested at a 95% confidence interval. Significant differences (
p
<
0.05) are highlighted in bold. Signifi-
cant differences (
p
≤
0.05) between variables in the groups are indicated with the same superscript letters.
TABLE 5. STEPWISE FORWARD REGRESSIONANALYSES OF CARDIOVASCULARANDANTHROPOMETRIC
VARIABLES PREDICTING HYPERTENSION IN CAUCASIANAND BLACKWOMEN
Caucasian women
African women
Adjusted
R
2
β
(
±
SE)
p
-value
Adjusted
R
2
β
(
±
SE)
p
-value
SBP
0.81
0.69 (0.11)
0.00
0.99
1.58 (0.13)
0.00
SV
0.84
0.59 (0.12)
0.39
0.94
0.15 (0.11)
0.02
Cw
0.79
–0.96 (0.01)
0.14
0.97
–0.18 (0.10)
0.03
β
denotes standardised regression coefficient and
F
to enter model, 2.5. Analyses adjusted for age, BMI, WC, CO, TPR, log CRP and log cortisol.
