Kidney size and function in a multi-ethnic population-based cohort of school-age children

Subclinical impaired kidney growth and function in childhood may lead to kidney diseases and high blood pressure in adulthood. We assessed the cross-sectional associations of childhood characteristics with kidney size and function in a multi-ethnic cohort. This study was embedded in a population-based cohort study of 6,397 children with a median age of 6.0 years.Kidney volume, creatinine and cystatin C blood levels, microalbuminuria and blood pressure were measured, and glomerular filtration rate (GFR) was estimated. Childhood anthropometrics were positively associated with kidney volume, creatinine level and blood pressure (all p < 0.05). We observed ethnic differences in all kidney size and function measures (all p < 0.05). Children with smaller kidneys had higher creatinine and cystatin C blood levels, leading to a lower estimated GFR [difference 5.68 ml/min/1.73 m(2) (95 % confidence interval 5.14-6.12) per 1 standard deviation increase in kidney volume]. Larger kidney volume was associated with an increased risk of microalbuminuria. Childhood kidney volume and function are influenced by body mass index and ethnicity. Kidney volume is related with kidney function but not with blood pressure. These results may help to identify individuals at risk for kidney disease in an early stage.