Table 2 Smoking history among electronic cigarette users and conventional cigarette smokers (N = 70)

Smoking index (pack years)

20.5

17.7

0.222^t

Smoking duration (years)

2.2 ± 0.7

3.7 ± 1.5

 < 0.001^*t

Severity of nicotine dependence (FTND score), no. (%)

 • Moderate dependence

15 (42.9%)

0 (0%)

 < 0.001^*x

 • High dependence

20 (57.1%)

35 (100%)