Cadmium Exposure and Neurodevelopmental Outcomes in U.S. Children

Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 01/2012; 120(5):758-63. DOI: 10.1289/ehp.1104152
Source: PubMed


Low-level environmental cadmium exposure in children may be associated with adverse neurodevelopmental outcomes.
Our aim was to evaluate associations between urinary cadmium concentration and reported learning disability (LD), special education utilization, and attention deficit hyperactivity disorder (ADHD) in U.S. children using National Health and Nutrition Examination Survey (NHANES) data.
We analyzed data from a subset of participants in NHANES (1999-2004) who were 6-15 years of age and had spot urine samples analyzed for cadmium. Outcomes were assessed by parent or proxy-respondent report. We fit multivariable-adjusted logistic regression models to estimate associations between urinary cadmium and the outcomes.
When we compared children in the highest quartile of urinary cadmium with those in the lowest quartile, odds ratios adjusted for several potential confounders were 3.21 [95% confidence interval (CI): 1.43, 7.17] for LD, 3.00 (95% CI: 1.12, 8.01) for special education, and 0.67 (95% CI: 0.28, 1.61) for ADHD. There were no significant interactions with sex, but associations with LD and special education were somewhat stronger in males, and the trend in the ADHD analysis was only evident among those with blood lead levels above the median.
These findings suggest that children who have higher urinary cadmium concentrations may have increased risk of both LD and special education. Importantly, we observed these associations at exposure levels that were previously considered to be without adverse effects, and these levels are common among U.S. children.

  • Source
    • "The median U-Cd levels found in the urine of our volunteers are far lower than 1 μgCd/g creatinine, the European Food Safety Authority threshold value for protection against kidney damage, thereby suggesting the lack of an important exposure source of this metal (EFSA, 2009). However, a reduction in Cd exposure is still relevant as adverse effects have been reported for the kidney and on bone and neurodevelopmental deficits at U-Cd cr concentrations as low as 1 μgCd/g creatinine (Järup and Åkesson, 2009, Ciesielski et al., 2012). Even at lower concentrations (o0.50 μg/g creatinine) Cd has been reported to be associated with hypertension and cardiovascular disease (Tellez–Plaza et al., 2012b), breast cancer incidence (McElroy et al., 2006) and mortality (Menke et al., 2009; Adams et al., 2012). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Anti-smoking legislation has been associated with an improvement in health indicators. Since the cadmium (Cd) body burden in the general population is markedly increased by smoke exposure, we analyzed the impact of the more restrictive legislation that came into force in Spain in 2011 by measuring Cd and cotinine in first morning urine samples from 83 adults in Madrid (Spain) before (2010) and after (2011) introduction of this law. Individual pair-wise comparisons showed a reduction of creatinine corrected Cotinine and Cd levels for non-active smokers, i. e. those which urinary cotinine levels are below 50μg/L. After the application of the stricter law, cotinine levels in urine only decreased in non-active smokers who self-reported not to be exposed to second-hand smoke. The reduction in second hand smoke exposure was significantly higher in weekends (Friday to Sunday) than in working days (Monday to Thursday). The decrease in U-Cd was highly significant in non-active smokers and, in general, correlated with lower creatinine excretion. Therefore correction by creatinine could bias urinary Cd results, at least for cotinine levels higher than 500μg/L. The biochemical/toxicological benefits detected herein support the stricter application of anti-smoking legislation and emphasize the need to raise the awareness of the population as regards exposure at home. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · Nov 2014 · Environmental Research
  • Source
    • "ion between post - natal cadmium exposure and neuropsychological development . More recently Kippler et al . ( 2012 ) observed a decrease of À 0 . 8 points ( 95% CI : À 1 . 2 to À 0 . 4 ) in Full - Scale IQ at 5 years of age for a doubling of cadmium in maternal urine in early pregnancy , with these associations being stronger in girls than boys . Ciesielski et al . ( 2012 ) observed a significant association between postnatal cad - mium exposure and both learning disability and special education , this being stronger in boys ."
    [Show abstract] [Hide abstract]
    ABSTRACT: This study assessed the association between cadmium exposure and neuropsychological development in children from a region with high industrial and mining activities in southwestern Spain. We conducted a cross-sectional study with 261 children aged 6–9 years between January and March 2012. Cadmium exposure was measured in urine and hair of children, and neuropsychological development was assessed with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) and with three computerized tests from the Behavioral Assessment and Research System (BARS): Reaction Time Test (RTT), Continuous Performance Test (CPT) and Selective Attention Test (SAT). Multivariate linear regression models, adjusted for potential confounders, were used to estimate the association between neuropsychological development and cadmium exposure measured in urine and hair samples. Geometric means of urine and hair cadmium levels were 0.75 μg/g creatinine and 0.01 μg/g, respectively. We observed that doubling of levels of cadmium in urine was associated with a reduction of two points (95% CI: −3.8 to −0.4) in the Full-Scale intelligence quotient (IQ) in boys. By domains, association was statistically significant for Verbal Comprehension (β=−2.0; p=0.04) and close to the significance level for Perceptual Reasoning (β=−1.8; p=0.06). Among girls, only Verbal Comprehension showed suggestive associations with cadmium exposure (β=−1.7; p=0.06). Cadmium exposure is associated with cognitive delays in boys in our region. Our results provide additional evidence of the neurotoxic effect of low-level postnatal cadmium exposure among children, and support the hypothesis of differences between sexes in the neurotoxic effect of metals on children.
    Full-text · Article · Oct 2014 · Environmental Research
  • Source
    • "Cd is suspected to cause several other adverse health effects in humans, also at exposure levels found in the general population; however, results have not been consistent or causality had not been definitely demonstrated. Examples include neurodevelopmental effects (Cao et al. 2009; Ciesielski et al. 2012; Kippler et al. 2012a, 2012b), diabetes (Afridi et al. 2008; Barregard et al. 2013; Schwartz et al. 2003), and cardiovascular disease or mortality (Agarwal et al. 2011; Bao et al. 2009; Fagerberg et al. 2012, 2013; Li et al. 2011; Menke et al. 2009; Messner et al. 2009; Nakagawa et al. 2006; Nawrot et al. 2008; Nishijo et al. 2006; Peters et al. 2010; Tellez-Plaza et al. 2012b, 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Exposure to cadmium (Cd) has long been recognized as a health hazard, both in industry and in general populations with high exposure. Under the currently prevailing health risk assessment, the relationship between urinary Cd concentrations (U-Cd) and tubular proteinuria is used. However, doubts have recently been raised regarding the justification of basing the risk assessment on this relationship at very low exposure. The objective of this paper is to review available information on health effects of Cd exposure with respect to human health risk assessment. The associations between U-Cd and U-proteins at very low exposure may not be due to Cd toxicity and the clinical significance of slight proteinuria may also be limited. More importantly, other effects have been reported at very low Cd exposure. There is reason to challenge the basis of the existing health risk assessment for Cd. Our review of the literature found that exposure to low concentrations of Cd is associated with effects on bone including increased risk of osteoporosis and fractures, and that this observation has implications for the health risk assessment of Cd. Other effects associated with Cd should also be considered, in particular cancer, though the information is still too limited for appropriate use in quantitative risk assessment. Non-renal effects should be considered critical effects in the health risk assessment of Cd.
    Full-text · Article · Feb 2014 · Environmental Health Perspectives
Show more