Effect of body size and malnutrition on renal size in childhood

Abstract

Malnutrition is associated with multi-organ manifestations including urinary concentrating defects. The purpose of our study was to prospectively determine the effect of body size and malnutrition on kidney size in children. The length and width of both kidneys were assessed in 525 children with no renal disease (289 male: 236 female; age: newborn-12 years) by real time ultrasonography. The nutritional status was assessed using the Indian Academy of Pediatrics classification, where the expected weight (EW) for age is the 50th percentile for Harvard statistics. Thus, Grade 0: 86100% of EW; Grade I: 70-80% of EW, Grade 11: 60-70% of EW; Grade 111: 50-60% of EW; Grade IV:< 50% of EW. There was no difference in renal size between males and females, or between right and left kidneys. The relationship between kidney area and age and grade of malnutrition was as follows: kidney area (mm2)=13.74 age (months) -110.9 grade+ 1265 (P< 0.001). The partial r for grade and age were -0.318 (P< 0.001) and 0.849 (P< 0.001), respectively. Normal Indian children (Grade 0) had smaller kidneys than those obtained in age matched children in the Western world. We conclude that severe malnutrition (Grade IV) reduces kidney size independent of age. Furthermore, we attribute the smaller kidney size in normal (grade 0) children, to the smaller body habitus of Indian children. Age based data alone, which are widely used currentIy to determine if kidney size is appropriate, may not be sufficient in geographic regions where malnutrition is prevalent and/or the growth curves of the population vary from Western derived standards.

Level and Determinants of Kidney Function in a South Asian Population in Pakistan

“…(16) (20) This was true even for the normotensive, non-diabetic adults in our study whom the mean GFR level was 94.1 +/− 27.8 ml/min/1.73 m 2 . It is possible that variation in dietary protein intake and nutritional status may explain some of the marked differences in GFR levels among studies.…”

“…(15) This stems primarily from earlier reports of small kidneys in South Asian children as well as low levels of measured GFR (mean of about 81 ml/min/1.73 m 2 ) in young potential kidney donors in India. (16) (17) Moreover, dietary protein consumption, which is known to be associated with lower GFR, may be lower in South Asians than in Western counterparts. (18) (19) Hence, some have suggested that low GFR levels in this population are usual and do not suggest the presence of CKD(17) (20).…”

Glomerular filtration rates in healthy Asians without kidney disease

“…It is known that malnourished Indian children have smaller kidneys when compared with their age‐matched subjects without malnutrition. And overall, Indian children tended to have smaller kidneys when compared with children in the West even in the absence of kidney disease . However, Barai described a similar kidney size when corrected for body surface area in Indians compared with Caucasian population in a more recent study …”