Table 1 Baseline characteristics of the study sample presented separately for EC users and control subjects who completed all four study visits.

From: Health impact of E-cigarettes: a prospective 3.5-year study of regular daily users who have never smoked

  EC users (n = 9) Control subjects (n = 12) p value
Sex (M/F) 6/3 8/4
Age (yrs, mean ± SD) 26.6 ± 6.0 27.8 ± 5.2 0.61
Duration of vaping hx (months, median [range]) 8 (3.5–15) N/A
Daily e-liquid consumption (ml, median [range]) 4.0 (2–5) N/A
E-liquid nicotine strengths (%) 0%: 3 N/A  
0.9%: 2
1.2%: 2
1.6%: 1
1.8%: 1
E-liquid flavour type Tobacco: 7 N/A  
Mint: 1
Fruit: 1
Device type Advanced refillable*: 4 N/A  
Standard refillable**: 5
Weight (kg, mean ± SD) 71.3 ± 11.2 72.9 ± 11.8 0.76
Systolic blood pressure (mmHg, mean ± SD) 115 ± 9 117 ± 9 0.59
Diastolic blood pressure (mmHg, mean ± SD) 79 ± 6 74 ± 9 0.20
Heart rate (beats/min, mean ± SD) 72 ± 7 79 ± 9 0.04
eCO (ppm, median and IQ range) 5.0 (3.5–7.3) 4.0 (3.5–7.5) 0.97¥
FeNO (ppb, median and IQ range) 21.1 (16.2–24.5) 18.6 (17.6–25.7) 0.75¥
FEV1 (% predicted, mean ± SD) 95.9 ± 9.4 104.8 ± 11.3 0.09
FVC (% predicted, mean ± SD) 102.0 ± 8.3 108.0 ± 8.4 0.12
FEV1/FVC (%, mean ± SD) 78.5 ± 3.5 81.4 ± 5.0 0.07
FEF25–75% (% predicted, mean ± SD) 75.3 ± 9.2 82.6 ± 18.7 0.30