Associations between cadmium exposure and neurocognitive test scores in a cross-sectional study of US adults

Abstract

BackgroundLow-level environmental cadmium exposure and neurotoxicity has not been well studied in adults. Our goal was to evaluate associations between neurocognitive exam scores and a biomarker of cumulative cadmium exposure among adults in the Third National Health and Nutrition Examination Survey (NHANES III).MethodsNHANES III is a nationally representative cross-sectional survey of the U.S. population conducted between 1988 and 1994. We analyzed data from a subset of participants, age 20–59, who participated in a computer-based neurocognitive evaluation. There were four outcome measures: the Simple Reaction Time Test (SRTT: visual motor speed), the Symbol Digit Substitution Test (SDST: attention/perception), the Serial Digit Learning Test (SDLT) trials-to-criterion, and the SDLT total-error-score (SDLT-tests: learning recall/short-term memory). We fit multivariable-adjusted models to estimate associations between urinary cadmium concentrations and test scores.Results5662 participants underwent neurocognitive screening, and 5572 (98%) of these had a urinary cadmium level available. Prior to multivariable-adjustment, higher urinary cadmium concentration was associated with worse performance in each of the 4 outcomes. After multivariable-adjustment most of these relationships were not significant, and age was the most influential variable in reducing the association magnitudes. However among never-smokers with no known occupational cadmium exposure the relationship between urinary cadmium and SDST score (attention/perception) was significant: a 1 μg/L increase in urinary cadmium corresponded to a 1.93% (95%CI: 0.05, 3.81) decrement in performance.ConclusionsThese results suggest that higher cumulative cadmium exposure in adults may be related to subtly decreased performance in tasks requiring attention and perception, particularly among those adults whose cadmium exposure is primarily though diet (no smoking or work based cadmium exposure). This association was observed among exposure levels that have been considered to be without adverse effects and these levels are common in U.S. adults. Thus further research into the potential neurocognitive effects of cadmium exposure is warranted. Because cumulative cadmium exposure may mediate some of the effects of age and smoking on cognition, adjusting for these variables may result in the underestimation of associations with cumulative cadmium exposure. Prospective studies that include never-smokers and non-occupationally exposed individuals are needed to clarify these issues.

The New Inconvenient Truth: Global Contamination of Food by Chemical Pollutants, Particularly Heavy Metals and Metalloids

“…Cadmium exposure is also associated with an increase in cancer susceptibility in type-2 diabetes, and a prolonged exposure to the metal is associated with pre-diabetes, diabetes, and overall cancer mortality which is sex-dependent in some types of cancer (30). A study by Ciesielski et al (31) suggests a link between higher cumulative Cd exposure to levels that have been considered safe and subtly decreased performance in attention-and perception-related tasks by adults especially those whose primary exposure is food. These levels of Cd are reportedly common among adults in the US.…”

Chromium, Cadmium, and Lead Dynamics During Winter Foliar Litter Decomposition in an Alpine Forest River

“…Chromium (Cr), cadmium (Cd), and lead (Pb) are common heavy metals that, even at relatively low levels, are related to various human diseases, such as oral cancer (Chiang et al, 2011), neurocognitive decline (Ciesielski et al, 2013), bone and cardiovascular disease, and renal dysfunction (Calderon, 2000;Watt et al, 2000). These heavy metals have also been reported to significantly damage the physiological activities of plants (Lyubenova et al, 2013;Kováčik et al, 2014).…”

Memory and fine motor skill test performance among children living near coal ash storage sites.

“…Metals such as cadmium, lead, mercury, chromium, manganese, and arsenic have been associated with impaired neurobehavioral performance in past studies (Chia et al, 1997;Ciesielski et al, 2013;Grashow et al, 2013;Gunther et al, 1996;Needleman et al, 1990;Rodriguez-Barranco et al, 2014;Schwartz et al, 2005;Wright et al, 2006). However, none of the study participants had nail levels of cadmium, lead, or mercury that exceeded the PIXE's level of detection.…”

“…Cadmium was a metal of interest in this thesis as it was related to decreased neurobehavioral performance in past studies (Ciesielski et al, 2013;Ciesielski et al, 2012;Rodriguez-Barranco et al, 2014). Of the studies reviewed, only one reported cadmium levels in nails that may reach PIXE's limit of detection, and those were at the upper bound of the concentration range found among adults occupationally exposed to cadmium (range: 0.214 -35.714 ppm; Mehra & Juneja, 2004).…”

“…shown that mercury, lead, and cadmium exposures are linked to problems with fine motor skills and memory (Gunther, Sietman, & Seeber, 1996;Chia, Chia, Ong, & Jeyaratnam, 1997;Grashow et al, 2013;Schwartz et al, 2005;Ciesielski, Bellinger, Schwartz, Hauser, & Wright, 2013;).…”