Table 2:

Pearson correlation coefficients between puff count, puff duration, inter-puff interval, frequency of puff clusters, and measures of e-liquid consumption and nicotine intake and exposure.

	Amount of e-liquid consumed^†	Amount of nicotine inhaled^†	C_max	AUC_0→90
Strawberry e-liquid
Puff count	0.72^**	0.72^**	0.45	0.43
Puff duration	0.27	0.27	0.16	0.21
Inter-puff interval	−0.50	−0.50	−0.32	−0.30
1–5 puffs (n)	−0.28	−0.28	0.11	0.06
6–10 puffs (n)	0.20	0.20	0.27	0.22
>10 puffs (n)	0.69^**	0.69^**	0.27	0.30
Tobacco e-liquid
Puff count	0.83^***	0.83^***	0.68^**	0.71^*
Puff duration	0.59^*	0.59^*	0.59^*	0.53^*
Inter-puff interval	−0.53	−0.53	−0.41	−0.45
1–5 puffs (n)	−0.21	−0.21	−0.05	−0.11
6–10 puffs (n)	0.31	0.31	0.26	0.30
>10 puffs (n)	0.74^**	0.74^**	0.57^*	0.62^*
Usual brand e-liquids
Puff count	0.82^***	0.08	−0.10	−0.10
Puff duration	−0.11	−0.09	−0.05	0.07
Inter-puff interval	−0.72^**	−0.12	0.06	0.13
E-liquid nicotine	−0.62^*	0.52	0.65^*	0.62^*
1–5 puffs (n)	−0.58^*	−0.14	−0.04	−0.04
6–10 puffs (n)	0.36	0.30	0.16	0.09
>10 puffs (n)	0.85^***	0.10	−0.06	−0.05

Note: Data are for all 14 participants;

p < 0.05;

^**

p < 0.01;

^***

p < 0.001;

^†

statistics are identical for amount of e-liquid consumed and amount of nicotine inhaled for the strawberry and tobacco e-liquids, respectively, because the nicotine concentration of each of these e-liquid was fixed during the study. Amount of nicotine inhaled is a function of amount of e-liquid consumed and e-liquid nicotine concentration.