Prenatal Lead Exposure and Blood Pressure in Children: Possible Effect Modification by Socioeconomic Status

Abstract

Prenatal Lead Exposure and Blood Pressure in Children: Possible Effect Modification by Socioeconomic StatusAbstract Number:2309 Roman Pabayo*, Howard Hu, Aimin Zhang, Brisa Sanchez, Adrienne Ettinger, Karen Peterson, Sung Kyun Park, David Cantonwine, Lourdes Schnaas, Robin O. Wright, Hector Lamadrid-Figueroa, Martha Maria Tellez-Rojo Roman Pabayo* Harvard School of Public Health, United States, E-mail Address: [email protected] Search for more papers by this author , Howard Hu Dalla Lana School of Public Health, University of Toronto, Canada, E-mail Address: [email protected] Search for more papers by this author , Aimin Zhang University of Michigan, School of Public Health, Department of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , Brisa Sanchez University of Michigan, School of Public Health, Department of Biostatistics, United States, E-mail Address: [email protected] Search for more papers by this author , Adrienne Ettinger Yale School of Public Health, Department of Epidemiology, United States, E-mail Address: [email protected] Search for more papers by this author , Karen Peterson University of Michigan, School of Public Health, Department of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , Sung Kyun Park University of Michigan, School of Public Health, Department of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , David Cantonwine University of Michigan, School of Public Health, Department of Environmental Health Sciences, United States, E-mail Address: [email protected] Search for more papers by this author , Lourdes Schnaas Division of Public Health, National Institute of Perinatology, Mexico City, Distrito Federal, Mexico Search for more papers by this author , Robin O. Wright Mount Sinai Hospital Search for more papers by this author , Hector Lamadrid-Figueroa Division of Statistics, Center for Evaluation Research and Surveys, National Institute of Public Health Search for more papers by this author , and Martha Maria Tellez-Rojo Division of Statistics, Center for Evaluation Research and Surveys, National Institute of Public Health, E-mail Address: [email protected] Search for more papers by this author AbstractBackground: Cumulative environmental lead exposure to the fetus is a predisposing risk factor for higher blood pressure (BP) during childhood. We investigated whether Socioeconomic Status (SES) moderated the relationship between prenatal lead exposure and blood pressure in 7 to 15 year-old boys and girls.Methods: We evaluated 457 mother-child pairs, originally recruited for an environmental birth cohort study between 1994 and 2003 in Mexico City that comprise the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT), and at a follow-up visit in 2008-2010. Prenatal lead exposure was assessed by measurement of maternal tibia and patella bone and umbilical cord lead. A SES score was calculated using a wealth index, education of the mother, education of the father, and mother’s marital status. The median score was used as a threshold for low vs. high SES. Models for SBP and DBP were simultaneously fitted using generalized estimating equations. Analyses were stratified by sex and by the median of the SES score, marital status of the mother and by education.Results: After adjusting for socio-demographic and nutritional covariates, umbilical cord lead was significantly associated with SBP among boys from low SES backgrounds only. Among low SES boys, an interquartile range increase in umbilical cord lead was associated with 4.14-mm Hg [95% confidence interval (CI)=1.76, 6.52] increases in SBP. Tibia bone lead was associated with SBP among boys whose mothers do not have a post- secondary education (ß=2.07, 95% CI=0.13,4.00) only. Among girls whose mothers were single, an interquartile increase in tibia lead exposure was associated with a 1.86 mmHg (95% CI=0.08, 3.64) and 2.02-mmHg (95% CI: 0.37,3.68) increases in SBP and DBP, respectively.Conclusions: Lead exposure is associated with increased BP among children from low SES backgrounds. SES may be a proxy for another factor that may cause a biological vulnerability to lead that has an impact on BP.