Background Low birth weight (LBW) is associated with a higher risk of end-stage renal disease (ESRD). The relative impacts of absolute birth weight, birth weight in relation to gestational age and preterm birth are, however, uncertain. Methods The Medical Birth Registry of Norway has since 1967 recorded data on all births. All patients with ESRD since 1980 have been registered in the Norwegian Renal Registry. Data from these registries were linked. All individuals registered in the Medical Birth Registry were included and the development of ESRD was used as endpoint in Cox regression statistics. LBW and LBW for gestational age [small for gestational age (SGA)] according to the 10th percentiles were used as the main predictor variables. Results Of the 2 679 967 included subjects, 1181 developed ESRD. Compared with subjects without LBW, subjects with LBW had an adjusted hazard ratio (aHR) for ESRD of 1.61 (1.38–1.98). SGA had an aHR of 1.44 (1.22– 1.70). Further analyses showed that as compared with subjects who had none of the risk factors LBW, SGA and preterm birth, subjects with one risk factor had an aHR of 1.05 (0.84–1.31), subjects with two risk factors had an aHR of 1.67 (1.40–1.98) and subjects with three risk factors had an aHR of 2.96 (1.84–4.76). Conclusions We conclude that LBW was associated with increased risk for ESRD during the first 50 years. Our analyses add to previous knowledge showing that only subjects with at least two of the risk factors LBW, SGA or preterm birth have increased risk.

Background and objectivesPrevious studies have shown that individuals with low birth weight (LBW) or small for gestational age (SGA) have higher risk of kidney failure. This study investigates birth-related exposures and risk of CKD and other kidney diagnoses.Design, setting, participant, & measurements The Medical Birth Registry of Norway has registered extensive medical data on all births in Norway since 1967. The Norwegian Patient Registry has registered diagnostic codes for all admissions and outpatient visits to Norwegian hospitals since 2008. Data from these registries were linked, and risk of CKD and other groups of kidney disease were analyzed using logistic regression statistics. LBW (below the tenth percentile), SGA (birth weight below the tenth percentile for gestational age), and preterm birth (<37 weeks) were analyzed as exposures.ResultsA total of 2,663,010 individuals were included. After a mean follow-up of 26 years (maximum 50 years), 4495 had been diagnosed with CKD and 12,818 had been diagnosed with other groups of kidney disease. LBW was associated with an odds ratio (OR) for CKD of 1.72 (95% confidence interval [95% CI], 1.60 to 1.90), SGA with an OR of 1.79 (95% CI, 1.65 to 1.94), and preterm birth with an OR of 1.48 (95% CI, 1.33 to 1.66). Analyses using diagnosis of CKD at stages 3–5 as end point showed similar results. Results were similar for men and women. We analyzed adjusted ORs for other groups of kidney disease and found that LBW was associated with an adjusted OR of 1.44 (95% CI, 1.33 to 1.56) for acute kidney disease, 1.24 (95% CI, 1.14 to 1.36) for GN, 1.35 (95% CI, 1.17 to 1.56) for cystic kidney disease, and 1.15 (95% CI, 1.06 to 1.25) for kidney disease resulting from kidney or urinary tract malformations.ConclusionsLBW, SGA, and preterm birth are associated with higher risk of CKD in the first 50 years of life. Risk of other groups of kidney disease was less pronounced.PodcastThis article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_08_17_CJN04080320.mp3

Introduction: Previous studies have revealed that individuals with low birth weight (LBW) have higher risk of chronic kidney disease (CKD) and that LBW and CKD cluster in families. This study investigates how familial factors affect the association between birth-related risk markers and risk of CKD.Methods: The Medical Birth Registry (MBR) of Norway has registered all births in Norway since 1967. Sibling data were available through the Norwegian Population Registry. The Norwegian Patient Registry has registered diagnostic codes for all admissions and outpatient visits to Norwegian hospitals since 2008. Data from these registries were linked. Risk of CKD according to whether the individual himself or at least one of his siblings had LBW was analyzed using logistic regression statistics.