Blood Lead Level and Measured Glomerular Filtration Rate in Children with Chronic Kidney Disease

Abstract

Background: The role of environmental exposure to lead as a risk factor for chronic kidney disease (CKD) and its progression remains controversial, and most studies have been limited by a lack of direct glomerular filtration rate (GFR) measurement.Objective: We evaluated the association between lead exposure and GFR in children with CKD.Methods: In this cross-sectional study, we examined the association between blood lead levels (BLLs) and GFR measured by the plasma disappearance of iohexol among 391 participants in the Chronic Kidney Disease in Children (CKiD) prospective cohort study.Results: Median BLL and GFR were 1.2 µg/dL and 44.4 mL/min per 1.73 m2, respectively. The average percent change in GFR for each 1-µg/dL increase in BLL was –2.1 (95% CI: –6.0, 1.8). In analyses stratified by CKD diagnosis, the association between BLL and GFR was stronger among children with glomerular disease underlying CKD; in this group, each 1-µg/dL increase in BLL was associated with a –12.1 (95% CI: –22.2, –1.9) percent change in GFR. In analyses stratified by anemia status, each 1-µg/dL increase in BLL among those with and without anemia was associated with a –0.3 (95% CI: –7.2, 6.6) and –4.6 (95% CI: –8.9, –0.3) percent change in GFR, respectively.Conclusions: There was no significant association between BLL and directly measured GFR in this relatively large cohort of children with CKD, although associations were observed in some subgroups. Longitudinal analyses are needed to examine the temporal relationship between lead and GFR decline, and to further examine the impact of underlying cause of CKD and anemia/hemoglobin status among patients with CKD.

Renal function assessment in child and adolescent heart transplant recipients during routine cardiac catheterization

“…Assessment of GFR through iohexol plasma clearance is a new method that is increasingly accepted as a new gold standard for determining kidney function in children and adults . Iohexol is a safe, non‐ionic, low‐osmolar contrast agent of molecular weight 821 Da (Omnipaque).…”

Environmental exposures and pediatric kidney function and disease: A systematic review

“…This was a study in the general United States population which used standardized definitions and controlled for possible confounders (Fadrowski et al, 2010). The same authors also reported a decrease in measured GFR in a prospective cohort study of 391 American and Canadian children with CKD but this was also not significant (Fadrowski et al, 2013). Both studies by Fadrowski et al had larger study populations and adjusted for possible confounders, they are examples of high quality studies in this systematic review.…”

“…One study used an equation based on both creatinine and Cystatin C (Weaver et al, 2014). One study (Fadrowski et al, 2013) used measured GFR by plasma disappearance of iohexol. Not all studies adjusted for possible confounders such as age, gender, race/ethnicity, or BMI Z-scores (Tables 5–8).…”

Toxic environmental exposures and kidney health in children

“…The average percentage change in GFR for each 1 μg/dL increase in blood lead level was −2.1 (95 % CI −6.0 to 1.8). In analyses stratified by CKD diagnosis, the association between lead level and GFR was stronger among children with glomerular disease underlying CKD; in this group, each 1 μg/dL increase in lead level was associated with a −12.1 (95 % CI −22.2 to −1.9) percentage change in GFR [67]. Significantly elevated lead levels have also been reported in other pediatric CKD populations.…”