COMPARISON OF SELECTED ANTHROPOMETRIC INDICES FOR CRITERION- CATEGORISATION OF RURAL PRIMARY SCHOOL PUPILS IN ZARIA, NIGERIA

Abstract

The study aimed at using anthropometric indices (BMI and %BF) to compare the criterion-categorisation
for under-weight, normal-weight, overweight and obese among rural boys. And, if, criterion-
categorisation would classify participants in similar criteria. A cross-sectional study design with
stratified random sampling was employed. Two hundred and eighty-eight rural primary school boys aged
7 to 11 years served as exemplars. The study determined %BF criteria-categorisation and BMI, while,
peak height velocity (PHV) and Maturity Age (MA) were subtly determined. Descriptive (mean ± SD),
Pearson product relationship (r), McNemar’s and Kappa agreement tests were statistically employed, p ≤
0.05 was used for all level of significance. The 8 years old had the lowest (16 ± 1.3) BMI value and third-
lowest (9.6 ± 2.2) in %BF. The 7 and 9 years old had lower (9.4 ± 2.6 and 9.5 ± 4.2) %BF. The 11 years
old had the highest BMI (17.2 ± 1.9) and %BF (11.3 ± 4.7), and the lowest MA (3.2 ± 0.4). BMI classified
all participants as normal-weight in the categorisation-criteria, while, %BF revealed ³ 50% occurrences
among the LA groups for 7 to 10 years old, and the NA category for 11 years old. Thinness and normal-
weight categories at the BMI, and the LA and NA at the %BF category. Apart from 8 years old, all other
age groups presented significant and high positive relationships (r ≥ .50; p ≤ .05) in the BMI and %BF.
The BMI and MA offered negative significantly low (r = -0.25), medium (r = -0.46) relationships for 7 to
9 years old. The 10 and 11 years old offered a significant high negative relationship (r = -0.53; r = -0.54
respectively). The relationship between %BF and MA, BMI and MA offered similar propensities. The
possible agreement between the categorisation-criteria for %BF and BMI revealed poor (κ = -0.24), none
to slight (κ = 0.14 - κ = 0.19) and moderate (κ = 0.59) measure of agreement for 7, 9 – 11 and 8 years
old, respectively. Body mass and body stature increasingly vary with age. Therefore, the two procedures
used for the categorisation criteria does not categorise the same population most especially
incomparable nutritional categorisations. Adiposity that includes fat-free mass in the assessment protocol
should be utilised instead of BMI for more accurate categorisations.