CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 1, February 2012
AFRICA
29
and an informed consent form was signed prior to the start of
the study.
Experimental procedure
Every morning during the working week, physical activity meters
were fitted to four of the 200 teachers between 07:00 and 08:00.
Anthropometric measures, i.e. height and weight were taken into
consideration for activating the software of the Acticals
®
activity
monitor (Mini Mitter Co, Inc, Bend, OR, Montreal, Canada). The
educators then resumed their normal daily activities and were
transported at 16:30 to the Metabolic Unit research facility of
the North-West University. At 17:00, they were welcomed and
the four teachers each received his/her own private bedroom and
was familiarised with the experimental setup to lessen anticipa-
tion stress.
19
Pre-counselling for HIV/AIDS was done under supervision
by a trained registered nurse. They commenced with the first
part of the psychosocial battery at 17:30 under supervision of
registered psychologists. A standardised dinner (according to fat,
carbohydrate and protein content) was provided at 18:00 and the
last part of the psychosocial battery was completed after dinner.
Participants were advised to go to bed at 22:00 and instructed to
refrain from consuming food, alcohol, caffeine, smoking, exer-
cising and tooth brushing eight hours prior to saliva and blood
sampling.
12
At 05:45 the following morning, the participants were awak-
ened and anthropometric measurements were taken in triplicate
by registered anthropometrists according to standardised proce-
dures.We collected blood pressure measures, and saliva and blood
samples for cortisol assays from the teachers in semi-Fowlers
position in two identical blood pressure stations at two different
times (sampling time 1; 06:30–07:00, included teachers 1 and 2,
and sampling time 2; 08:30–09:00, included teachers 3 and 4).
Procedures in the two identical blood pressure stations were
as follows: blood pressure measurements according to the Rocci/
Korotkoff method were taken, followed by resting Finometer
blood pressure, and saliva and blood sampling for cortisol
determinations. Blood pressure responses were obtained during
stressor application while blood sampling was done 10 minutes
after stressor exposure. Cortisol saliva responses were sampled
30 minutes after stressor exposure. The same procedure was
followed for the second stressor. The two identical blood pres-
sure stations followed exactly the same protocol (
±
1.5 hours)
under supervision of a registered nurse and doctor. Ultrasound
scanning for carotid intima–media thickness (CIMT) followed.
Immediate feedback was given on available data and post-coun-
selling regarding HIV status and referrals were made. Thereafter,
they received incentives and breakfast, and went back to school.
Anthropometric measurements
Height was measured with an Invicta Stadiometer (IP 1465,
UK) to the nearest 0.1 cm while the participant’s head was in
the Frankfort plane. Heels were together, with the buttocks and
upper back touching the stadiometer. Mass was measured to the
nearest 0.1 kg on a KRUPS scale with the participant wearing
minimal clothing and with the weight evenly distributed. Height
and mass were used to calculate body mass index (BMI). Waist
circumferences (WC) were measured with the participant in a
standing position (A & D Company, Japan, Holtain unstretch-
able flexible 7-mm-wide metal tapes). The WC was taken at the
midpoint between the lower costal border and the iliac crest,
perpendicular to the long axis of the trunk.
Blood pressure measurements
Participants were in semi-Fowlers position in the blood pres-
sure stations. After a five-minute rest period, two Riva-Rocci/
Korotkoff blood pressure measurements were obtained, with a
five-minute rest period between measurements. A suitable cuff
size was applied to the non-dominant arm. The second measure-
ment classified participants as hypertensive according to the cut-
off points of the European Society of Hypertension Guidelines
(Korotkoff sound I: resting SBP
≥
140 mmHg and/or Korotkoff
sound V: resting DBP
≥
90 mmHg).
20
Non-invasive continuous
beat-to-beat arterial blood pressure recordings were obtained
with the Finometer device.
21
Results were analysed with the Fast
Modelflo computer program to provide systolic (SBP) and dias-
tolic blood pressure (DBP), cardiac output (CO), total peripheral
resistance (TPR) and arterial compliance (Cw) values.
Salivary cortisol levels
Resting salivary cortisol levels were obtained 45 minutes
after awakening, avoiding the cortisol awakening response
(CAR).
12
Cortisol saliva stressor responses were obtained 30
minutes after exposure to each stressor. Cortisol sampling was
done at sampling time 1 (06:30–07:00) and sampling time 2
(08:30–09:00). Optimal hygienic collection of saliva was done
with the Salivette
®
cortisol (Art. No. 51.1534.500) containing a
synthetic swab, which was chewed for 45 seconds to one minute
and immediately frozen at –80ºC. The cortisol recovery rate in
Salivette
®
cortisol is proven to be almost 100% (Sarstedt AG &
Co. Nümbrecht, Germany).
Stressors
Participants were subjected to mental stressors for one minute
in a counterbalanced design, including the Stroop color–word
interference task (CWC) and the cold pressor test (CPT), which
involved the immersion of the left foot up to the ankle in ice
water (4°C).
22
They received monetary incentive as motivation
on completion of the Stroop cards.
Carotid–intima media thickness (CIMT)
A high-resolution ultrasound carotid intima–media scan
23
deter-
mined target end-organ damage. CIMT images from at least
two optimum angles of the left and the right common carotid
artery, carotid bulb and internal carotid arterial (ICA) segments
were acquired using a Sonosite Micromaxx ultrasound system
(SonoSite Inc., Bothell, WA, USA) and a six- to 13-MHz linear
array transducer, using the Rudy Meijer protocol.
23
The images
were digitised and imported into the AIMS automated software
for dedicated analysis of CIMT. A maximal 10-mm segment with
good image qualitywas chosen for analysis.The programautomat-
ically identifies the borders of the CIMT of the near and far wall.
Questionnaires
The Coping strategy indicator (CSI) of Amirkhan,
24
which
has been successfully used in the South African context, was
