Reference indices for evaluating kidney dimensions in children using anthropometric measurements

BACKGROUND: Kidney pathologies often result in change in renal size. Knowledge of normal kidney sizes is important for screening, diagnosis, prognosis and follow-up management of paediatric renal diseases. OBJECTIVES: The aim of this study was to establish the age-, height- and weight-matched kidney dimensions in apparently healthy Nigerian children. METHOD: A descriptive, cross-sectional study of right and left kidney parameters (length, width, thickness and volume) of 1315 school-aged Nigerian children was conducted over 8 months. Ages ranged from 5 to 17 years. Parameters were obtained using a General Electric (GE) LOGIC 400CL ultrasound machine. Kidney dimensions were correlated with age, sex and anthropometric measurements. RESULTS: Normative values for all the kidney parameters for each age, height and weight groups and also gender were established for the study population. The left kidneys were noted to be longer and thicker, and of more volume than the right kidneys. The right kidneys were seen to be wider (p < 0.01). Length of the left kidneys in females was noted to be more than those of the males in the age- and weight-matched categories (p < 0.05). The width of both kidneys was higher in the males in all the categories (p < 0.05). Males showed higher values of thickness and volume in the height category. All the renal parameters significantly correlated with body size indicators, except for body mass index. CONCLUSION: This study has established gender-, age-, weight- and height-specific range of values of the kidney parameters of apparently healthy children together with regression models.