Table 1.
Mean (SD) and Median PG and VG Concentrations for Daily ECIG Users and Controls
| ECIG users (N = 42) | Controls (N = 50) | |
|---|---|---|
| PG concentration (mcg/ml) | ||
| Mean (SD) | 25.6 (20.0) | 9.8 (13.5) |
| Median | 20.9 | 3.2 |
| PG concentration abstinent (mcg/ml) | ||
| Mean (SD) | 9.7 (15.0) | n.a |
| Median | 4.9 | n.a. |
| VG concentration (mcg/ml) | ||
| Mean (SD) | 7.5 (7.1) | 13.2 (25.0) |
| Median | 5.1 | 4.4 |
| VG concentration abstinent (mcg/ml) | ||
| Mean (SD) | 5.0 (4.4) | n.a. |
| Median | 4.1 | n.a. |
Mean (SD) and median values for urine propylene glycol (PG) and vegetable glycerin (VG) concentration for daily ECIG users pre and post 12-hour ECIG/nicotine abstinence and for controls. Urine PG and VG normalized for creatinine. n.a. = not applicable/not measured; control group did not undergo an abstinence period as they were not users of ECIGs or nicotine/tobacco products. For controls, urine VG concentrations are presented with two outliers included whose urine VG concentrations were 5–6 times greater than the mean, possibly due to greater than average exposures to VG-containing food and/or products. Upon removal of these two outliers, mean urine VG concentration was 8.1 mcg/ml (SD=10.9) for controls (N=48).