RELATIONSHIP BETWEEN RENAL SIZE AS DETERMINED BY ULTRASONOGRAPHY AND BODY MASS INDEX IN APPARENTLY HEALTHY PRIMARY SCHOOL CHILDREN IN PORT HARCOURT, NIGERIA

RELATIONSHIP BETWEEN RENAL SIZE AS DETERMINED BY ULTRASONOGRAPHY AND BODY MASS INDEX IN APPARENTLY HEALTHY PRIMARY SCHOOL CHILDREN IN PORT HARCOURT, NIGERIA

Abstract

Renal size is an important parameter in clinical evaluation and
management of a child with kidney disease as the renal size may
be an important indicator of kidney function. Renal size shows
variation with age, sex and body parameters including body
mass index (BMI). Hence establishing the renal size pattern
standardized against somatometric parameters will be a useful
tool in detecting probable renal diseases among children. Thus
the aim of this study was to determine renal sizes in relation to
BMI in apparently healthy primary school children in Port
Harcourt, Rivers State.
This was a cross sectional school based study carried out over a
period of six months between October 2015 and March 2016. A
total of 455 children aged 6-12 years were selected from 18
schools in Port Harcourt using multistage sampling method.
Renal ultrasonography was carried out on all selected subjects
(using a portable real time ultrasound machine model DP-1100
PLUS MINDRAY fitted with 3.5MHz curvilinear probe). The
renal length, renal width and anteroposterior diameter of the
kidneys were measured and renal volume calculated. Weight and
height were measured using Seca model DT01 weighing scale
and stadiometer model RGZ-160 respectively. BMI was
calculated as weight (kg)/height2 (m2) and the BMI percentile for
age and sex obtained.
The subjects comprised 226(49.7%) males and 229(50.3%)
females. The overall mean renal length were 81.5±7.4mm and
80.9±7.6mm of the right and left kidneys respectively while the
overall mean renal volume were 52.1±15.4 × 103 (mm3) and
52.2±15.4 × 103 (mm3) of the right and left kidneys respectively.
There was no significant difference between the right and left
renal length and volume. The difference in the mean renal sizes
across different age groups was statistically significant. There
was no significant gender difference in renal sizes. The mean
BMI of the subjects was 16.5±2.5kg/m2 and there was no
significant gender difference in the overall mean BMI of the
study subjects (t= 0.774, p= 0.439). A total of 318(69.9%)
subjects had normal weight, 46(10.1%) were underweight,
39(8.6%) were overweight and 52 (11.4%) were obese. The renal
length and volume of the overweight/obese children were
significantly higher than those of the normal weight children.
However there was no significant difference between the renal
length of the normal weight and underweight children.
(p=<0.05). Age and BMI were independent predictors of renal
length and volume.
In conclusion, the mean renal length and volume increased with
increasing age in school age children and BMI had a significant
positive linear relationship with renal length and volume.
Multicenter studies on renal sizes among children in Nigeria is
recommended to establish age, gender and BMI specific renal
size normograms.

RELATIONSHIP BETWEEN RENAL SIZE AS DETERMINED BY ULTRASONOGRAPHY AND BODY MASS INDEX IN APPARENTLY HEALTHY PRIMARY SCHOOL CHILDREN IN PORT HARCOURT, NIGERIA

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