TABLE 2

Biomarkers of Nicotine, Tobacco-Specific Nitrosamine, and Volatile Organic Toxicants in Exclusive E-Cigarette–Only Users Versus Dual Users and Controls

VariableE-Cigarette–Only Users,an = 67Dual Users,bn = 16Controls,cn = 20
MediandIQRRangeMedianeIQRRangeMedianeIQRRange
Saliva cotinine (ng/mL)03.80–864.699.4**139.036.2–302.80*00
Urine NNAL (pg/mL of creatinine)0.30.70–0.968.1**68.732.7–299.30**00
PMA (ng/mg of creatinine; benzene)00.10–2.00.2**0.70–2.4000–0.1
MHBMA (ng/mg of creatinine; 1,3-butadiene)000–2.200.10–0.20*0.50–1.1
HEMA (ng/mg of creatinine; ethylene oxide)0.51.10–7.61.0*1.40–8.21.32.30–4.0
CNEMA (ng/mg of creatinine; acrylonitrile)1.33.20–108.459.4**81.33.7–142.60**1.10–1.6
3-HPMA (ng/mg of creatinine; acrolein)254.3191.40–2311.6439.7*224.1153.6–814.4192.8*261.60–1416.4
2-HPMA (ng/mg of creatinine; propylene oxide)28.8250–1382.640.227.910.2–310.915.2**14.40–34.5
AAMA (ng/mg of creatinine; acrylamide)67.3690–581.2235.6**239.841.4–574.734.5**41.60–182.0
HMPMA (ng/mg of creatinine; crotonaldehyde)148.7990–793.4185.4156.6110.0–437.9100.4*129.90–522.1
  • All comparisons were made with e-cigarette–only users as a comparison group. IQR, interquartile range; MHBMA, 4-hydroxy-2-buten-1-yl-mercapturic acid.

  • a Used an e-cigarette product in the past 24 h and had NNAL levels <1 pg/mL of creatinine.

  • b Used an e-cigarette product in the past 24 h, smoked a cigarette in the past 30 d, and had NNAL levels ≥30 pg/mL of creatinine.

  • c No use of tobacco or e-cigarette in the past 30 d, with NNAL levels <1 pg/mL of creatinine and cotinine levels <1 ng/mL.

  • d The median (IQR) was reported for cotinine, NNAL (pg/mL of creatinine), and VOCs (ng/mg of creatinine) because of non-normal distribution.

  • e Tests were based on regression models of log-transformed values, including planned covariates (sex and race and/or ethnicity) with contrasts for e-cigarette–only users versus controls and for e-cigarette–only users versus dual users.

  • * P < .05; ** P < .001.