Albuminuria: Population epidemiology and concordance in Australian children aged 11-12 years and their parents

Objectives To describe the distribution of albuminuria among Australian children aged 11.12 years and their parents, and assess its intergenerational concordance within parent.child dyads.

Design Population-based cross-sectional study (the Child Health CheckPoint), nested within the Longitudinal Study of Australian Children.

Setting Assessment centres (seven Australian cities and eight regional towns) and home visits across Australia, February 2015 to March 2016.

Participants Of all participating CheckPoint families (n=1874), 1557 children (46.2% girls) and 1454 parents (85.5% mothers) provided random urine samples at the visit; samples from menstruating females were excluded.

Outcome measures Urine albumin-to-creatinine ratio (ACR) and its components (urine albumin and creatinine concentration); albuminuria was defined as an ACR .3.4 mg/mmol. Pearsonfs correlation coefficients and multivariable linear regression models assessed parent. child concordance, using log-transformed data due to skewing. Survey weights and methods were applied to account for the complex sample design.

Results The median ACR for children was 1.03 mg/mmol (IQR 0.65.1.97) and 1.01 mg/mmol (IQR 0.60.2.09) for adults. The median ACR was higher in girls (1.20, IQR 0.71.2.65) than boys (0.90, IQR 0.61.1.65) and in mothers (1.13, IQR 0.63.2.33) than fathers (0.66, IQR 0.41.1.05). Albuminuria was detected in 15.1% of children (girls 20.8%, boys 10.1%) and 13.5% of adults (15.1% mothers, 4.0% fathers) had albuminuria. There was a small correlation between parent and child ACR (Pearson correlation coefficient 0.06, 95% CI 0.01 to 0.12).

Conclusions Albuminuria is common among Australian children and adults, which is of concern because it predicts risk for kidney and cardiovascular disease, and mortality. The weak concordance among intergenerational pairs for urine ACR suggests either that genetic heritability is low or that it becomes evident only at later offspring life stages.