Longitudinal relationship between albuminuria in infancy and childhood.

Background: Mildly increased albuminuria is common in the general adult population and is a strong predictor for cardiovascular events, even in otherwise healthy individuals. The underlying pathophysiological process could be endothelial dysfunction. Previously, we reported that increased albuminuria can also be found in 2-year-olds from the general population. We hypothesized that some individuals have constitutionally higher levels of albuminuria, possibly as an expression of early or inborn endothelial dysfunction. The aim of this study is to evaluate longitudinal persistence of albuminuria from infancy into school age.

Methods: In the population-based GECKO (Groningen Expert Center for Kids with Obesity) cohort, urine was collected from 816 children at the age of 2 years as well as 12 years (random urine and first morning void urine, respectively). We evaluated prevalence and persistence of increased albuminuria (U ≥ 3 mg/mmol) at the two time points.

Results: The prevalence of U ≥ 3 mg/mmol at 2 and 12 years of age was 31.9% (95% CI 28.7-35.2) and 3.1% (95% CI 2.0-4.5), respectively. U < 3 mg/mmol at both 2 and 12 years of age was present in 540 children (66.2%). Only 9 children (3.5%) of the 260 children with an U ≥ 3 mg/mmol at 2 years had an U ≥ 3 mg/mmol at 12 years (p < 0.001).

Conclusion: Albuminuria in 2-year-olds does largely not persist until the age of 12, indicating that albuminuria at 2 years of age is not a marker for constitutional endothelial dysfunction in this cohort. A higher resolution version of the Graphical abstract is available as Supplementary information.