Cardiovascular Journal of Africa: Vol 30 No 6 (November/December 2019)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 6, November/December 2019 348 AFRICA
and triceps) was measured three times with the use of a Slim
Guide skinfold calliper, and the values were rounded to the
nearest 0.1 mm.14
Bi-acromial width was measured while the subject was in a
relaxed standing position with the arms hanging at the sides,
using the branches of the large sliding calliper. They were
placed on the most lateral points of the acromion processes at
an angle of 90 degrees pointing upwards. Pressure was applied
to compress the overlying tissue without moving the shoulders.
Bi-iliocristal width was measured using the branches of the
anthropometer held at 45 degrees pointing upwards on the most
lateral points on the iliac crests, with firm pressure applied to
reduce the effect of the overlying tissue.
Transverse chest width was measured using the superior aspect
of the calliper scale at the level of the front mesosternale and the
blades were positioned at an angle of 30 degrees downwards. The
calliper was positioned at the lateral borders of the ribs. Anterior–
posterior chest depth was measured using the branches of the
calliper placed on the level of the mesosternale. The rounded tips
of the calliper were held between the thumb and digits two and
three over the right shoulder while the subject breathed normally.
The rear branch of the calliper was positioned on the spinous
process of the vertebra at the horizontal level of the mesosternale
and measurement was taken at end-tidal expiration.
Chest girthwas measured around the thorax using ameasuring
tape at the level of the mesosternale. During the measurement
the subjects lowered the abducted arms to a relaxed position
but still abducted horizontally. Waist girth was measured at the
level of the narrowest point between the lower costal border (rib)
and the iliac crest using a measuring tape with the arms slightly
abducted to a relaxed position. Gluteal girth was measured 1 cm
below the level of the gluteal fold, perpendicularly to the long
axis of the thigh, using a measuring tape while the subject’s feet
were together and the gluteal muscles relaxed.
It was customary in the Polokwane private school project
to aggregate numbers so that individual identity was obscured.
A standard data-collection form designed by investigators was
used in the study. After the information had been captured
electronically, the data forms were kept safe under lock and key to
safeguard the identity of the subjects. The principal investigator
discarded personal identity information when consolidating data
for the purpose of statistical analysis.
Statistical analysis
Descriptive statistics were expressed for weight, height, BMI,
triceps, subscapular and abdominal skinfolds, sum of skinfolds,
bi-acromial width, anterior–posterior chest depth, transverse
chest depth, bi-iliocristal width, and waist, gluteal and chest
girth by age group of critical periods in childhood for the
development of obesity [adipose rebound (five to seven years),
adolescence (eight to 10 years and 11–15 years)]15 and gender.
Pearson correlation coefficients was performed to determine the
relationship between adiposity (BMI, waist girth, gluteal girth,
abdominal, triceps and subscapular skinfolds, sum of skinfolds)
and body frame variables (bi-acromial width, anterior–posterior
chest depth, transverse chest depth, bi-iliocristal width and chest
girth) by age group. All the data were analysed with a statistical
package for social sciences (SPSS) version 23. A statistically
significant difference was assumed at p < 0.05.
Results
Table 1 shows the descriptive statistics for adiposity and body
frame variables among Polokwane private school children.
Boys in the age group 11 to 15 years had a higher mean height
(132.4 cm) than boys in age group five to seven years (103.7 cm).
Adiposity status based on sum of skinfolds for girls in age group
five to seven years had a slightly lower mean (19.2) than girls in
age group 11 to 15 years (19.7). The highest prevalence of obesity
was among girls in age group eight to 10 years (5.5%) while boys
in age group 11 to 15 years had the highest prevalence of mild
undernutrition (23.8%).
Table 2 shows Pearson correlation coefficients for body
frame and adiposity variables among Polokwane private school
children for age group five to seven years. There was a negative
significant correlation between BMI (reflects adiposity) with
height only (reflects body frame) (r2 = –0.303). There was
Table 1. Descriptive statistics for body frame and adiposity variables
among Polokwane private school children by gender and age group
Age group
5–7 years 8–10 years 11–15 years
Boys Girls Boys Girls Boys Girls
Variables M (SD) M (SD) M (SD) M (SD) M (SD) M (SD)
Number 88 74 361 348 677 614
Age 7.2
(0.54)
7.1
(0.53)
9.5
(0.91)
9.5
(0.88)
12.3
(0.92)
12.1
(0.73)
Weight 14.6
(1.74)
14.4
(2.34)
19.0
(3.24)
18.8
(3.13)
24.3
(3.60)
24.2
(4.25)
Height 103.7
(5.74)
102.9
(6.75)
118.5
(7.96)
118.5
(7.59)
132.4
(6.67)
132.0
(6.82)
Body mass index 13.5
(1.15)
13.6
(2.30)
13.5
(1.16)
13.3
(1.40)
13.8
(1.26)
13.8
(1.55)
Triceps skinfold 7.0
(1.76)
7.2
(1.88)
5.9
(1.38)
6.7
(1.62)
5.9
(1.53)
7.3
(2.28)
Subscapular skinfold 5.2
(1.15)
5.5
(1.31)
4.8
(0.78)
5.2
(1.05)
5.0
(0.91)
5.85
(1.58)
Abdominal skinfold 5.5
(1.35)
6.4
(1.85)
5.0
(1.08)
5.7
(1.51)
5.2
(1.41)
6.5
(3.55)
Sum skinfolds 17.7
(3.40)
19.2
(4.28)
15.7
(2.68)
17.5
(3.52)
16.0
(3.18)
19.7
(6.24)
Bi-acromial width 21.4
(1.64)
21.2
(1.87)
24.7
(1.91)
24.5
(1.94)
27.0
(1.91)
26.6
(2.11)
A-P chest 11.8
(1.12)
11.3
(0.95)
12.5
(1.12)
12.1
(0.99)
13.2
(1.02)
12.9
(1.30)
Transverse chest 16.1
(1.29)
15.7
(1.35)
17.6
(1.32)
17.2
(1.23)
19.0
(1.33)
18.7
(1.52)
Bi-iliocristal width 15.0
(1.05)
14.8
(1.25)
16.5
(1.35)
16.4
(1.17)
17.8
(1.20)
17.8
(1.45)
Waist girth 48.9
(2.81)
47.6
(2.80)
50.7
(2.98)
49.8
(3.20)
53.2
(3.25)
52.1
(3.41)
Gluteal girth 51.3
(2.66)
51.9
(3.38)
55.5
(4.00)
56.8
(4.13)
60.9
(4.07)
62.4
(4.99)
Chest girth 50.5
(2.18)
49.6
(2.88)
54.3
(2.72)
53.1
(2.80)
58.0
(3.10)
56.8
(3.21)
The prevalence of overweight, obesity and undernutrition % (n)
Overweight 8.9
(17)
7.9
(17)
10.3
(35)
9.8
(32)
6.3
(20)
13.8
(38)
Obesity 1.0
(2)
0
(0)
2.4
(8)
5.5
(18)
2.5
(8)
2.2
(6)
Mild undernutrition 14.1
(27)
19.4
(42)
13.0
(44)
15.6
(51)
23.8
(75)
11.6
(32)
Moderate undernutrition 8.3
(16)
4.6
(10)
3.5
(12)
2.4
(8)
3.8
(12)
4.0
(11)
Severe undernutrition 8.3
(16)
10.2
(22)
2.1
(7)
2.4
(8)
0.6
(2)
1.8
(5)
*p < 0.05; **p < 0.01.