Zinc Intake Is Associated with Lower Cadmium Burden in U.S. Adults.
BACKGROUND
Cadmium is a toxic transition metal whose absorption and accumulation might depend on zinc intake.


OBJECTIVE
We sought to determine whether zinc intake and serum zinc would be inversely associated with cadmium exposure.


METHODS
This study used data from NHANES 2003-2012, from which there were 6678 and 6488 participants with urinary and blood cadmium data, respectively, and 1195 participants with serum zinc data. Mean blood and urinary cadmium were reported by quintiles of zinc intake and by the dose and duration of zinc supplement use. The associations between zinc intake from diet and supplements, serum zinc, and blood and urinary cadmium were determined using multiple regression. Analyses were adjusted for age, body mass index, race/ethnicity, gender, income-to-poverty ratio, education, smoking status, and mean intakes of energy, calcium, and iron.


RESULTS
Urinary cadmium concentrations were 0.04 μg/g creatinine lower among participants in the highest compared with lowest quintile of total zinc intake (P-trend = 0.0041). Zinc supplement dose and duration were inversely associated with blood cadmium (P = 0.0372) and serum zinc (P-trend = 0.0017), respectively. In adjusted regression models, a 10% increase in total zinc intake corresponded to a predicted decrease in blood cadmium of 0.42% (95% CI: -0.79%, -0.06%; P = 0.0260) and in urinary cadmium of 0.42% (95% CI: -0.81%, -0.04%; P = 0.0340). A 10% increase in serum zinc was associated with a predicted 1.99% (95% CI: -3.17%, -0.81%; P = 0.0012) decrease in blood cadmium and a predicted 4.09% (95% CI: 2.14%, 6.04%, P = 0.0001) increase in urinary cadmium.


CONCLUSIONS
Dietary and serum zinc in US adults are associated with cadmium exposure, presumably by influencing the absorption and accumulation of cadmium. Whether the degree of reduction in cadmium exposure from greater zinc intake and status is causal or relevant from a public health perspective needs further investigation.
Department of Nutritional Sciences, University of Connecticut, Storrs, CT.
Terrence M
http://orcid.org/0000-0002-0647-0295
TM
Vance
Department of Nutritional Sciences, University of Connecticut, Storrs, CT ock.chun@uconn.edu.
Ock K
http://orcid.org/0000-0002-7391-2380
OK
Chun
D000328:Adult; D002104:Cadmium / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine*; D004032:Diet; D019587:Dietary Supplements; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012044:Regression Analysis; D012907:Smoking; D014481:United States; D015032:Zinc / Q000008:administration & dosage* / Q000097:blood
D002104:Cadmium; D015032:Zinc
NHANES; cadmium; diet; exposure; zinc