TABLE 2.
Concentrations of mercapturic acid metabolites of volatile organic compounds (VOCs) measured in 24-hour urine during e-cigarette use
| Exposure (Biomarker) (ng/mg creatinine) |
Cig-a-like (mean, SD) (n = 12) |
Fixed-power (mean, SD) (n = 15) |
Variable-power (mean, SD) (n = 6) |
Pod (mean, SD) (n = 3) |
Difference (p value) |
|
|---|---|---|---|---|---|---|
| All included |
Pods excluded |
|||||
| Acrolein (3-HPMA) | 260.6 (236.0) | 238.7 (189.8) | 340.7 (173.1) | 188.0 (49.9) | 0.081 | 0.100 |
| Acrylamide (AAMA) | 117.4 (65.9) | 103.2 (43.6) | 118.8 (35.1) | 131.9 (58.9) | 0.325 | 0.311 |
| Acrylonitrile (CNEMA) | 27.5 (28.6) | 20.8 (15.6) | 17.1 (3.79) | 13.1 (13.4) | 0.442 | 0.950 |
| 1,3-Butadiene (MHBMA-1+2) | 0.51 (0.36) | 0.57 (0.50) | 0.50 (0.43) | 0.19 (0.07) | 0.055 | 0.730 |
| 1,3-Butadiene (MHBMA-3) | 0.16 (0.09) | 0.15 (0.09) | 0.24 (0.23) | 0.08 (0.05) | 0.019 | 0.363 |
| Benzene (PMA) | 0.54 (0.22) | 0.48 (0.41) | 0.38 (0.20) | 0.39 (0.19) | 0.081 | 0.129 |
| Crotonaldehyde (HPMMA) | 152.4 (68.0) | 194.2 (128.6) | 132.5 (30.5) | 171.3 (71.6) | 0.477 | 0.242 |
| Ethylene oxide (HEMA) | 1.56 (0.64) | 1.35 (1.25) | 1.73 (1.31) | 1.27 (1.40) | 0.090 | 0.124 |
| Methylating agent (MMA) | 15.7 (9.3) | 18.8 (27.0) | 18.7 (23.7) | 13.6 (12.8) | 0.601 | 0.865 |
| Propylene oxide (2-HPMA) | 34.2 (17.4) | 62.6 (55.0) | 75.8 (26.4) | 42.2 (19.6) | <0.001 | 0.001 |
Notes: 2-HPMA = 2-hydroxypropylmercapturic acid; 3-HPMA = 3-hydroxypropylmercapturic acid; AAMA = 2-carbamoylethylmercapturic acid; CNEMA = 2-cyanoethylmercapturic acid; HEMA = 2-hydroxyethylmercapturic acid (acrylonitrile, vinyl chloride, ethylene oxide); HPMMA = 3-hydroxy-1-methyl-propylmercapturic acid; MHBMA-1+2 = sum of isomers 1-hydroxy-3-buten-2-yl-mercapturic acid and 2-hydroxy-3-buten-1-yl-mercapturic acid; MHBMA-3 = 4-hydroxy-2-buten-1-yl-mercapturic acid; MMA = methylmercapturic acid; and, PMA = phenylmercapturic acid.