Metal Mixtures in Urban and Rural Population in the United States: Evidence fromthe Multi-Ethnic Study of Atherosclerosis and the Strong Heart Study

metal;Epidemiology

Pang, YuanjieNavas-Acien, Ana ;

Johns Hopkins University

关键词: metal;    Epidemiology;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/38116/PANG-THESIS-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Introduction: Natural and anthropogenic sources of metal exposure are different for residents of urban and rural areas. The objectives of this study were to evaluate metal-mixtures and allocate potential environmental sources of different urinary metals, and to compare metal-mixtures in two population-based studies in the United States: the Multi-Ethnic Study of Atherosclerosis (MESA) conducted in 6 urban areas, and the Strong Heart Study (SHS) conducted in 3 rural areas. Methods: We studied 308 White, Chinese, Black and Hispanic adult participants in MESA (2000-2002 examination), and 105 American Indian adult participants in SHS (1998-2003 examination). Participants were selected at random and stratified by site for metal measurements. Nine metals (As, Cd, Mo, Pb, Sb, Se, U, W and Zn) were measured in spot urine specimens by inductively coupled plasma-mass spectrometry. For arsenic, we used the sum of inorganic and methylated species (∑As). We used principal component analysis (PCA), cluster analysis (CA), and linear discriminant analysis (LDA) to evaluate metal-mixtures. We accounted for urine dilution by standardizing metal concentrations by specific gravity.Results: Levels of ∑As, Cd, U, W and Zn were higher in SHS participants as compared with MESA participants. PCA and CA revealed consistent patterns in SHS, suggesting 4 distinct principal components (PC) or clusters (∑As-U-W, Mo-Se, Pb-Sb, Cd-Zn). In MESA, CA showed 2 large clusters (∑As-Mo-Sb-U-W, Cd-Pb-Se-Zn), while PCA showed 4 components (Sb-Se-Zn, Pb-U-W, Cd-Mo, ∑As-Pb). After adjusting for rice intake in MESA, PCA and CA showed more similar findings. LDA indicated that ∑As was the most discriminant variable distinguishing MESA and SHS participants. Conclusions: The ∑As-U-W urinary cluster and PC in SHS might reflect groundwater contamination in rural areas. The Cd-Zn cluster and PC in SHS could reflect common sources from processed meat and interactions in metabolic pathways for those metals. Among our 9 metals, ∑As had the highest discriminant ability to distinguish participants from MESA and SHS, reflecting disproportionate inorganic arsenic exposure in rural tribal communities compared to urban communities around the US.