Summary
Introduction:
This text summarizes a scientific study investigating the potential transfer of metals from electronic cigarette (e-cigarette) devices to the generated aerosol and how this exposure can increase metal body burden in e-cigarette users. The study recruited 75 e-cigarette users and 25 non-users and analyzed metal concentrations in e-liquid samples before and after being added to devices, as well as in aerosol samples, urine, and hair.
Key Points:
* E-cigarette users had higher metal concentrations in the aerosol and tank e-liquid (in contact with the coil) compared to the dispenser e-liquid (before contact with the coil).
* Median concentrations for some of the metals with the most remarkable increases in aerosol and tank e-liquid vs. dispenser e-liquid were 36.90 and 62.73 vs. 18.29 μg/kg for al; 6.71 and 28.97 vs. 0.98 μg/kg for Cr; 91.39 and 414.47 vs. 1.64 μg/kg for Ni; 738.99 and 744.24 vs. 16.56 μg/kg for Zn; and 10.17 and 22.31 vs. 0.88 μg/kg for Pb.
* In urine, increases in the median levels (μg/g creatinine) in vapers/duals vs. controls were observed for some metals, including Cr (0.34/0.28 vs. 0.20), Cu (1.72/2.36 vs. 1.46), Sn (0.26/0.31 vs. 0.18) and Pb (0.39/0.44 vs. 0.22).
* hair samples showed no significant differences in metal concentrations between the three groups.
* Exhaled breath condensate samples presented low or close to the LOD concentrations for the metals analyzed.
* Spearman correlations between metal levels in aerosol and metal levels in urine or hair for sole and dual e-cigarette users were mostly weak, non-significant, or negative.
* In regression models adjusted for age and sex, urinary Cr concentrations were not associated with Cr concentrations in the dispenser, aerosol, and tank samples, while associations with hair Cr were positive but significant only with dispenser Cr concentrations.
Main Message:
The study suggests that e-cigarettes are likely a source of metals, including Cr, Cu, Ni, Pb, or Sn, which come from the device, likely the heating resistance. Metal aerosol exposure can influence the body burden of metals in e-cigarette users, but aerosol metal levels were not clearly associated with metal levels in biological samples such as urine or hair in e-cigarette users in this study. More research is needed to understand the mechanisms of metal transfer in e-cigarettes.
Citation
Olmedo P, Rodrigo L, Grau-Pérez M, et al. Metal exposure and biomarker levels among e-cigarette users in Spain. Environmental research. 2021;202:111667. doi:10.1016/j.envres.2021.111667
