Race-specific relationship of birth weight and renal function among healthy young children

Background Low birth weight is associated with diminished renal function. However, despite African Americans being at increased risk of low birth weight and chronic kidney disease, little is known about the association between birth weight and renal function in diverse groups. We examined racial differences in the relationship of birth weight and renal function among healthy young children. Methods Birth weight and serum creatinine data were available on 152 children (61.8% African American; 47.4% female) from a birth cohort. Estimated glomerular filtration rate (eGFR) was calculated using the bedside Schwartz equation and gender- and gestational-age-adjusted birth weight Z-scores using the US population as a reference. Race-specific linear regression models were fit to estimate the association between birth weight Z-score and eGFR. Results Mean age was 1.5±1.3 years at first eGFR measurement. African Americans had lower eGFR than non-African Americans (median eGFR082 vs. 95 ml/min per 1.73 m²; p=0.06). Birth weight was significantly and positively associated with eGFR among African American (p=0.012) but not non-African American children (p=0.33). Conclusions We provide, for the first time, evidence suggesting that birth weight is associated with renal function in African American children. Future work is needed to determine if prenatal programming helps explain racial disparities in adult health.