Environmental exposure to cadmium is decreasing among adults and children in the US

Cadmium is a toxic transition metal with no known essential function in humans. A significant, but uncommon, source of cadmium exposure is occupation. More common sources of exposure are tobacco smoke and diet. While exposure is typically low among the general population, the human body has no effective way of eliminating cadmium. Chronic exposure to high amounts of cadmium has been associated with a greater risk of renal damage, heart disease, and several types of cancer. The cadmium from tobacco smoke and diet is predominantly industrial in origin. Cadmium is produced by and used in industrial processes, deposited in the soil, and may eventually be absorbed by plants or dissolved in water. Partly because of environmental and health concerns, the production and use of cadmium has been decreasing in the US over the past few decades. The objective of the current study was to examine the trends in and sources of cadmium exposure using data from NHANES 2003–2012 and the US Geological Survey. Blood and urinary levels of cadmium were used to assess cadmium exposure. After excluding people who lacked data on blood or urinary cadmium or smoking exposure, blood cadmium data were available for 22,728 adults (age > 20 years) and 13,063 children and adolescents (age < 20 years) and urinary cadmium data were available for 7,530 adults and 3,618 children and adolescents. Because smoking is the most significant source of cadmium exposure among the general US population, analyses of adults were stratified by smoking status (defined as never, past, or current). All analyses were further adjusted for age, gender, ethnicity, body mass index, serum cotinine, and poverty income ratio. From 2003 to 2012, blood cadmium levels decreased 3% and 7% among never and past smokers, respectively, and increased 4% among current smokers; however, none of these trends were statistically significant. Over the same time period, urinary cadmium levels decreased among never smokers by 17% (0.27 vs 0.22 μg/g creatinine, P‐trend < 0.0001), past smokers by 25% (0.36 vs 0.27 μg/g creatinine, P‐trend = 0.0004), and current smokers by 8% (0.38 vs 0.35 μg/g creatinine, P‐trend = 0.0483). Similar trends were observed among children and adolescents, with no change in blood cadmium and a 16% decrease in urinary cadmium (0.10 vs 0.08 μg/g creatinine, P‐trend = 0.0035). Over approximately the same time period, industrial production of cadmium decreased from 1,450 to 637 metric tons and apparent consumption decreased from 1,420 to 703 tons. The trends in urinary cadmium levels closely mirror that of industrial cadmium production and apparent consumption. These results suggest that industrial production and environmental contamination are important contributors to cadmium exposure in the US population, and exposure from these sources is decreasing. Support or Funding Information Supported by the SUNY College at Plattsburgh School of Education, Health & Human Services