CORRELATION OF BODY MASS INDEX AND INTELLIGENCE QUOTIENT AMONG SCHOOL CHILDREN AGED 6 – 12 YEARS IN ILORIN KWARA STATE NIGERIA

Abstract

Malnutrition is of public health importance as it ranks high among the leading causes of under
five morbidity and mortality. The problem of under-nutrition, which was the predominant form
of malnutrition seen in developing countries, has been heightened by its co-existence with over
nutrition as part of the emerging double burden of malnutrition. It influences the growth
potential, cognitive ability as well as the overall well being of the child. There are few data on
the impact of malnutrition on cognitive performance of children in this environment. The effect
of socio-economic class on both malnutrition and Intelligence Quotient (IQ) are worth
estimating. This study was carried out to determine the BMI and IQ of school children, to
determine the correlation between BMI and IQ, bearing in mind the effects of socio-economic
class (SEC) on intelligence quotient and BMI of school children in Ilorin.
This was a descriptive cross-sectional study conducted among primary school children aged 6 –
12 years. Subjects were selected via a multistage sampling technique. A total of 480 primary
school pupils were selected from eight public and eight private schools. Anthropometric
measurements were taken to determine indices of nutritional status (BMI, weight for age and
height for age), while IQ was determined using the Draw A Person Test (DAPT). Data were
analyzed using the statistical package for social sciences (SPSS) version 20. Significance of
categorical variables were determined using chi square while that between two or more means of
continuous variables were determined with the student t test or Analysis of variance (ANOVA)
respectively. There were 221 (46.0%) males and 259 (54.0%) females, giving a male to female ratio of 1:1.2.
The mean age of the children was 9.2 ± 1.8 years. The mean age of public school children (10.0
± 1.6 years) was significantly higher than that for the private school children (8.3 ± 1.7 years) p
< 0.0010. The mean BMI of the study population was 15.7 ± 2.4 kg/m². The mean BMI for
public school children (15.9 ± 2.3) was not significantly different from that for the private school
children (15.5 ± 2.4) p = 0.0910. The prevalence of underweight and stunting were 15.4% and
11.5% respectively, higher among public than the private school children. The prevalence of
overweight and obesity were 7.3% and 3.1% respectively, higher among private than the public
school children.
The mean IQ of the study population was 98.0 ± 14.1. The mean IQ of the private school
children (99.6 ± 15.2) was significantly higher than that for the public school children (96.5 ±
12.9) p < 0.0170. The prevalence of intellectual deficit and superior IQ in the study population
were 2.5% and 8.8% respectively. There was a significant positive correlation between IQ and
BMI (r = 0.3, p = 0.0001). While improved SEC correlates significantly with increased IQ, there
was no significant correlation found between SEC and BMI.
This study affirms the existent of a double burden of malnutrition among school children in
Ilorin with prevalence of underweight and overweight/obesity as 15.4% and 10.4% respectively.
Fewer proportions of school – aged children had intellectual deficit, which range from mild to
moderate forms of mental retardation. There was a significant positive correlation between BMI
and IQ, as well as SEC and IQ while there was none between SEC and BMI.
Routine nutritional (BMI) assessment of primary school children is advocated. The SEC of
parents should be improved upon to further reduce the burden of intellectual deficit.

CORRELATION OF BODY MASS INDEX AND INTELLIGENCE QUOTIENT AMONG SCHOOL CHILDREN AGED 6 – 12 YEARS IN ILORIN KWARA STATE NIGERIA