Correlation of Lead Poisoning and Intelligence Status of School Children in a Southern Nigerian Urban City

O. D. Emeagui, B. U. Ezeonwu, H. I. O. Opara, N. K.Emeagui, S. N. Okolo

Abstract

BACKGROUND: Lead is a heavy metal of utmost public health
significance in Nigeria. It is a known neurotoxin that impairs
neurotransmission and brain function resulting in cognitive
and motor deficits. Ingestion of lead contaminated food or water
is the major route of exposure to lead manifesting as neurologic
symptoms which can interfere with the intelligence of school
children.

AIM: To correlate the Intelligence quotient scores with the blood
lead levels of primary school children in Southern Nigeria.

METHODS: The study was a descriptive cross-sectional study
amongst primary school pupils, conducted in Asaba, the capital
of Delta state, Nigeria. Goodenough-Harris “Draw a Person
Test” validated by Ebigbo and Izuora in Enugu, Nigeria was
used to assess the intelligence of the pupils while blood lead
levels was measured with Flame Atomic Absorption
Spectrophotometer (FAAS).

RESULTS: Three hundred and twenty subjects were recruited.
Seventy-one subjects did not have lead poisoning (22%) while
two hundred and forty-nine subjects had lead poisoning
(77.8%). Mild, moderate and severe level lead poisoning
constituted 22.5% (56/249), 28.1% (70/249) and 49.4% (123/249)
respectively. Seventy percent (225) subjects had optimal IQ
while 95 subjects had sub-optimal IQ and mean IQ score was
92.9 ± 25.1. There was no association and correlation between
IQ status and levels of lead poisoning.

CONCLUSION: A significant proportion of school children
had optimal level of intelligence despite the high prevalence of
lead poisoning seen among them. There was no association or
correlation between different levels of childhood lead
poisoning and Intelligence quotient status. WAJM 2022; 39(3):
275–280.

Keywords: Lead poisoning, intelligence, childhood.