Table 4.

Correlations between self-reported water pipe use and time of exposure and changes in biomarkers^a

	COT_Δ1	COT_Δ2	NIC_Δ1	NIC_Δ2	NNAL_Δ1	NNAL_Δ2	2HPMA_Δ1	3HPMA_Δ1	AAMA_Δ1	CNEMA_Δ1	MHBMA_Δ1	HEMA_Δ1	PMA_Δ1
Time in bar	0.16	0.14	0.05	0.21	0.11	0.04	0.27^b	−0.28^b	0.13	0.05	0.18	0.03	0.07
Smoking duration	0.09	0.15	0.13	0.41^c	0.10	0.05	0.22	−0.10	−0.02	−0.06	0.15	-0.08	0.01
Number of bowls	0.27^b	0.18	0.17	0.11	0.10	0.08	0.05	−0.18	0.21	0.19	0.13	0.10	0.19
Bowls per user	0.35^c	0.28^b	0.10	0.08	0.18	0.14	0.12	−0.15	0.22	0.24	0.00	0.02	0.23
Prior SHS	0.21	0.25	0.02	0.22	0.21	0.26^b	−0.06	0.04	0.20	0.16	0.07	0.20	0.22

↵^aAll subjects included in the analysis; COT, cotinine; NIC, nicotine; NNAL, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol; VOC mercapturic acid metabolites (parent compound in parenthesis): 2HPMA, 2-hydroxypropyl (propylene oxide); 3-HPMA, 3-hydroxypropyl (acrolein); AAMA, 2-carbamoylethyl (acrylamide); CNEMA, cyanoethyl (acrylonitrile); MHBMA, 2-hydroxy-3-buten-1-yl or isomer(s) (1,3-butadiene); HEMA, 2-hydroxyethyl (ethylene oxide); PMA, phenyl (benzene); Δ₁, postexposure minus preexposure; Δ₂, next day minus preexposure; VOC mercapturic acid metabolites were only measured in preexposure and postexposure samples.
↵^bP < 0.05.
↵^cP < 0.01.