title: Impact of bone lead and bone resorption on plasma and whole blood lead levels during pregnancy.
abstract: The authors tested the hypotheses that maternal bone lead burden is associated with increasing maternal whole blood and plasma lead levels over the course of pregnancy and that this association is modified by rates of maternal bone resorption. A total of 193 Mexican women were evaluated (1997-1999) in the first, second, and third trimesters of pregnancy. Whole blood lead and plasma lead levels were measured in each trimester. Urine was analyzed for cross-linked N-telopeptides (NTx) of type I collagen, a biomarker of bone resorption. Patella and tibia lead levels were measured at 4 weeks postpartum. The relation between whole blood, plasma, and bone lead and NTx was assessed using mixed models. Plasma lead concentrations followed a U-shape, while NTx levels increased significantly during pregnancy. In a multivariate model, the authors observed a significant and positive interaction between NTx and bone lead when plasma lead was used as the outcome variable. Dietary calcium intake was inversely associated with plasma lead. Results for whole blood lead were similar but less pronounced. These results confirm previous evidence that bone resorption increases during pregnancy, with a consequential significant release of lead from bone, constituting an endogenous source of prenatal exposure. They also provide a rationale for testing strategies (e.g., nutritional supplementation with calcium) aimed at decreasing prenatal lead exposure.
authors.affiliation: Centro de Investigación en Salud Poblacional, Instituto Nacional de Salud Pública, Cuernavaca, Mexico. mtellez@insp.mx
authors.forename: Martha María
authors.initials: MM
authors.lastname: Téllez-Rojo
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hernández-Avila
authors.forename: Héctor
authors.initials: H
authors.lastname: Lamadrid-Figueroa
authors.forename: Donald
authors.initials: D
authors.lastname: Smith
authors.forename: Leticia
authors.initials: L
authors.lastname: Hernández-Cadena
authors.forename: Adriana
authors.initials: A
authors.lastname: Mercado
authors.forename: Antonio
authors.initials: A
authors.lastname: Aro
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Howard
authors.initials: H
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D001862:Bone Resorption; D001842:Bone and Bones / Q000737:chemistry; D002136:Calcium, Dietary; D005260:Female; D006801:Humans; D007854:Lead / Q000097:blood*; D008137:Longitudinal Studies; D015999:Multivariate Analysis; D011247:Pregnancy / Q000502:physiology*; D011248:Pregnancy Complications
chemical_list: D002136:Calcium, Dietary; D007854:Lead