Prevalence and associated demographic characteristics of exposure to multiple metals and their species in human populations: The United States NHANES, 2007–2012

Abstract

Lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) are among the top 10 pollutants of global public health concern. Studies have shown that exposures to these metals produce severe adverse effects. However the mechanisms underlying these effects, particularly joint toxicities, are poorly understood in humans. The objective of this investigation was to identify and characterize prevalent combinations of these metals and their species in the U.S. National Health and Nutrition Examination Survey (NHANES) population to provide background data for future studies of potential metal interactions. Exposure to each metal was defined as urine or blood levels ≥ respective medians of the NHANES 2007–2012 participants ≥6 years (n=7408). Adjusted-odds ratios (adj-OR) and 95% confidence intervals (CI) were determined for demographic factors (age, gender, and race/ethnicity). All models included two additional covariates, cotinine and body mass index (BMI). Species-specific analysis was also conducted for As and Hg including iAs (urinary arsenous acid and/or arsenic acid), met-iAs (urinary monomethylarsonic acid and/or dimethylarsinic acid), and oHg (blood methyl-mercury and/or ethyl-mercury). For combinations of As and Hg species, age- and gender-specific prevalence was determined among NHANES 2011–2012 participants (n=2342). Approximately 49.3% of the U.S. population were exposed to a combination of three or more metals. The most prevalent unique specific combinations were Pb/Cd/Hg/As, Pb/Cd/Hg, and Pb/Cd. Age was consistently associated with these combinations: adj-ORs ranged from 10.9 (Pb/Cd) to 11.2 (Pb/Cd/Hg/As). Race/ethnicity was significant for Pb/Cd/Hg/As. Among women of reproductive age, frequency of oHg/iAs/met-iAS and oHg/met-iAs was 22.9 and 40.3%, respectively. These findings of metals and their species in human population may help prioritize efforts to assess joint toxicities and their impact on public health.

A Comparison of the Nephrotoxicity of Low Doses of Cadmium and Lead

“…None of the participants in the present study had been exposed to metals in the workplace, and their urinary concentrations of Cd and Pb were thus presumed to reflect environmental sources, notably diet [5,49]. The urinary Cd and Pb concentrations were similar to the data obtained from population-based studies in the U.S. [9][10][11][12], Canada [13], Taiwan [14] and Korea [15]. The eGFR was calculated by using CKD-EPI equations, which are considered to be the most accurate equations for the eGFR [20,22].…”

“…The International Agency for Research on Cancer has established Cd as a human carcinogen [6], while the carcinogenicity of chronic Pb exposure in workplace settings has been observed in two large prospective cohort studies [7,8]. Co-exposure to low levels of environmental Cd and Pb has been reported in large population-based studies in the U.S. [9][10][11][12], Canada [13], Taiwan [14], and Korea [15]. About half of the participants in the U.S. National Health and Nutrition Examination Surveys (NHANES) 2007-2012, aged ≥6 years, had blood or urinary levels of Cd and Pb above reported median levels [11].…”

Cytomegalovirus seroprevalence, recurrence, and antibody levels

“…Covariates hypothesized to be potential confounders of the relations between toxic metal biomarkers and CMV infection, recurrence, and IgG levels included age, sex, race/ethnicity, socioeconomic status, nativity, and tobacco smoke exposure as these factors have either been related to toxic metal exposures and increased susceptibility to infections in general or CMV in particular. 37 , 44 , 47 – 49 Household crowding was additionally studied as an independent risk factor for CMV exposure (Figure 2 ). 50 , 51 During household interviews conducted by trained study staff, participants were asked to self-report sociodemographic and housing characteristics.…”

A Review of Biomarkers Used for Assessing Human Exposure to Metals from E-Waste

“…6 Set by US Center for Disease Control and National Institute of Occupational Safety and Health [48]. 7 NHANES median value [49]. 8 95th %ile from the German Environmental Survey 1990–1992 [50,51].…”