LAUSR

Introduction We have previously showed that albuminuria was associated with low birthweight in young adults in a remote Australian Aboriginal community that has high rates of kidney disease. Here we describe the association of birthweight with incidence and progression of kidney disease over time. Methods Among 695 members of an Aboriginal community with recorded birthweights, urine albumin creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR) were measured at ages 5 to 40 years, and follow-up values were measured or imputed again a median of 11.6 years later. Prevalence of markers on each occasion and change over time were evaluated in the context of birthweights and other potentially significant factors. Results On the second screen, ACR was inversely and significantly correlated with birthweight and eGFR was directly correlated with birthweight. Increases in ACR and in proportions of persons who developed new-onset (incident) albuminuria between screens were higher in those of lower birthweights (<2.5 kg). Proportions of persons who lost ≥20% of their baseline eGFR were higher in the lower birthweight groups. Lower birthweights also amplified elevations of ACR associated with other risk factors, specifically higher body mass indexes (BMIs) and a prior history of poststreptococcal glomerulonephritis (PSGN). At both screens, progressively higher levels of ACR beyond the mid-microalbuminuria range were correlated with lower levels of eGFR. Conclusions Lower birthweight contributes to an excess of kidney disease and its progression in this population. Because an excess of low birthweight and episodes of PSGN are eminently preventable, substantial containment of kidney disease is feasible.