Table 2

Waterpipe smoking topography measures, CO and plasma nicotine by condition and smoking group status (N=143)

	Flavoured					Unflavoured
	Low-frequency users (n=69)		High-frequency users (n=74)		P value*	Low-frequency users (n=69)		High-frequency users (n=74)		P value*
	Mean	SD	Mean	SD	P value*	Mean	SD	Mean	SD	P value*
Total smoke time (min)	42:54	7:37	42:02	8:02	0.509	40:06†	9:42	40:56	9:05	0.599
Cumulative puffing time (min)	4:59	3:14	6:13	3:46	0.037	4:16	2:41	5:18†	3:06	0.034
Average puff duration (s)	3.08	1.27	3.68	1.77	0.023	3.05	1.22	3.51	1.5	0.060
Average IPI (s)	28.17	17.57	25.77	17.14	0.410	31.69	19.91	28.36	19.55	0.316
Total no of puffs	106.63	64.00	111.93	86.37	0.679	96.94	66.46	104.76	86.50	0.549
Total inhaled volume (L)	51.16	33.31	81.50	54.73	< 0.001	53.53	33.35	78.92	51.81	0.001
Average puff volume (L)	0.57	0.35	0.78	0.42	0.001	0.66†	0.35	2.04	8.52	0.185
eCO boost (ppm)	12.1	11.7	30.72	33.27	< 0.001	17.52†	14.63	33.37	27.60	< 0.001
Nicotine boost (ng/mL)	4.33	0.58	10.45	1.17	< 0.001	5.69†	0.81	9.09	0.97	0.008

Bold numbers indicate statistical significance at p<0.05
*P value indicates the significant difference between smoking groups within tobacco conditions.
†Sign indicates a significant difference between flavoured and unflavoured for that smoking group (p<0.05).
CO, carbon monoxide; IPI, interpuff interval; eCO, expired carbon monoxide.