Table 5.

Variables predicting ad libitum D₀-nicotine glucuronidation^a in a multivariate regression model in current smokers

Variable	nb	Parameter estimate	p
CYP2A6 normal allelesc	88	−0.009 ± 0.003	0.003
CYP2A6*1A	16	−0.007 ± 0.003	0.02
CYP2A6*9	6	−0.007 ± 0.004	0.09
UGT2B10*2 (67Y)	11	−0.007 ± 0.002	0.0007
UGT2B10*3 (481D)	2	0.012 ± 0.005	0.02
Total adjusted R2		0.37

Results of linear regression analyses treating CYP2A6 null alleles (CYP2A6*2, *4, *12 and *38) and UGT2B10*1 as the reference. Genetic variables are coded as number of haplotypes per subject (0,1,2). Negative parameter estimates indicate reduced nicotine glucuronidation relative to the reference genotype.

^aNon-deuterated (D₀)-(nicotine-glucuronide / (nicotine-glucuronide + nicotine + cotinine + cotinine-glucuronide + trans-3′-hydroxycotinine))

^bnumber of alleles

^call CYP2A6 alleles excluding CYP2A6*1A, *9 and assumed null alleles CYP2A6*2, *4, *12 and *38.