CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 1, February 2012
28
AFRICA
Cardiovascular, cortisol and coping responses in urban
Africans: the SAPBA study
D MEYBURGH, L MALAN, JM VAN ROOYEN, JC POTGIETER
Abstract
Objectives:
To assess the relationships between progression of
target-organ damage and cardiovascular, cortisol and coping
responses in black urban Africans.
Methods:
Urban black African gender groups (
n
=
200) aged
21–62 years from the Sympathetic Activity and Ambulatory
Blood Pressure in Africans study were stratified into normo-
tensive and hypertensive groups. Resting and reactivity
Finometer blood pressure, fasting sodium fluoride glucose
and salivary cortisol values were obtained before and after
applying the Stroop and cold pressor tests. Coping strate-
gies were determined and high-resolution ultrasound carotid
intima–media scans were done to determine progression of
target-organ damage.
Results:
A trend of high-normal resting cortisol values during
sampling time 1 was demonstrated in all hypertensive men.
Both hypertensive gender groups showed increased vascular
responses during both mental stressors. During the cold pres-
sor test, vascular responses predicted sub-clinical atheroscle-
rosis in all hypertensive men, independent of sampling time.
Conclusion:
Early morning vascular responses in all the
hypertensive men could have occurred secondarily to the
permissive effect of cortisol on norepinephrine secretion,
with subsequent
α
-adrenergic vasoconstriction. Their
α
-adrenergic vascular responses during the cold pressor test,
however, predicted sub-clinical atherosclerosis, independent
of sampling time and cortisol level.
Keywords:
cardiovascular, cortisol, coping, responses, Africans
Submitted 26/11/09, accepted 30/11/10
Cardiovasc J Afr
2012;
23
: 28–33
DOI: 10.5830/CVJA-2010-101
Exposure to chronic stress is a good predictor of future
cardiovascular disease (CVD),
1
and the risk for CVD is mostly
increased by an exaggerated blood pressure (BP) response to
stress,
1-6
especially in Africans.
7
Hypertensives have more reac-
tive cardiovascular systems, indicated by greater vascular reac-
tivity, enhanced hypothalamic–pituitary–adrenal axis (HPAA)
activity and enhanced salivary cortisol levels when stressed.
3
Psychological appraisal of stress could contribute to cardio-
vascular dysregulation through endothelial dysfunction and
changes in vascular function.
4,5
Persistent psychosocial stress
resulting from urban living in Africans could also lead to
increased allostatic load and decreased ability to cope.
6,7
The
negative effect that psychosocial stress could have on a person’s
health and well-being could, however, be either minimised or
exacerbated by his/her choice of coping response.
8
Coping can
be defined as deliberate and effortful attempts to manage situ-
ations that we appraise as potentially harmful or stressful.
9
This
includes constantly changing cognitive and behavioural attempts
to control the internal and external demands of the situation,
which exceed the resources of a person.
10
Malan
et al
.
11
revealed that urban Africans indicated behav-
ioural control when using an active coping or problem-solving
strategy but contradictorily showed higher cardiovascular risk
than rural African men. These findings are opposed to the find-
ings of O’Donnell
et al.
, revealing that Caucasian individuals
who coped by problem engagement and seeking social support
had lower cortisol levels and possibly lower CVD risk.
12-14
Chronic stress can lead to dysregulation of the HPAA with
resultant increased circulating adrenocorticotropic hormone
(ACTH), cortisol, corticosterone, impaired feedback regulation
of the axis and impaired glucocorticoid receptor binding in the
hippocampus.
15
This could indicate the role of glucocorticoids in
central control of the cardiovascular system during stress.
16
Roy
et al
. suggested that resting rather than cortisol stress responses
plays a permissive role in sympathetically driven cardiovascular
stress responses.
17
Since stress and related health impairments have become
major problems in human life, investigation of the psychobiolog-
ical pathways that link stress and disease are of major importance
in black Africans with a high prevalence of hypertension.
11,18
Therefore, the objective of the study was to assess the relation-
ship between cardiovascular, cortisol and coping responses in
urban Africans, as well as its contribution towards progression
of target-organ damage (TOD).
Methods
The SABPA study was a target-population study that included a
sample of 200 black African teachers, aged 21 to 62 years, in the
Dr Kenneth Kaunda educational district, North-West Province.
Hereafter, the black Africans (
n
=
101 men,
n
=
99 women) will
be referred to as Africans. Exclusion criteria for the study were:
pregnancy, lactation, temperature above 37ºC and users of alpha-
and beta-blockers. Participants included had not donated blood
or been vaccinated in the previous three months.
Permission to participate was granted by the North-West
Education Department and support ensured from the South
African Democratic Teachers’ Union. The ethics committee of
the North-West University approved the study (00036-07-S6)
and the study protocol conforms to the revised ethical guidelines
of the Declaration of Helsinki, 2004. A standard subject infor-
mation sheet was given to the subjects at their screening visit,
School for Physiology, Nutrition and Consumer Sciences,
North-West University, Potchefstroom, South Africa
D MEYBURGH, MSc
L MALAN, RN, PhD,
JM VAN ROOYEN, DSc
School for Psychosocial Behavioural Sciences, North-West
University, Potchefstroom, South Africa
JC POTGIETER, PhD
