Contribution of e-cigarette use to renal cadmium burden.

Recent expansion of the use of electronic cigarettes (eCig) as a nicotine substitute for tobacco products has raised concerns regarding whether eCig vaping might adversely contribute to the body burden of heavy metals. Epidemiological studies found higher levels of cadmium (Cd) in blood and urine in association with eCig use, although this outcome is not consistent across all investigations. In this study, a biokinetic model was used to predict the relative contributions of diet and eCig vaping to renal and urinary Cd levels. The biokinetic model predicted that, for a median eCig exposure scenario, renal cortex Cd increased by 0.2 μg Cd/g and urine Cd rose by 0.004 μg Cd/g creatinine (Cr), a 5.6% elevation above the levels predicted for diet alone. For a 95th percentile eCig exposure, the rise was 2.2 μg Cd/g renal cortex and urine Cd increased by 0.04 μg Cd/g Cr, a 35% elevation above the level predicted for diet alone. The predicted increases in urine Cd attributed to eCig vaping were consistent with epidemiologic-based estimates of the impact of eCig use on urinary Cd levels, providing further support for eCig vaping constituting a potential contributor to the Cd body burden.