Table 2.

Frequencies of slow-metabolizing CYP2A6 haplotypes in non-dependent and dependent smokers

Haplotype namea	% Minor allele frequency
	European American			African American
	Non-Db	Dc	Pd	Non-Db	Dc	Pd
Number of subjects	933	1055		248	461
*1A(51A)	19.0	17.0	0.11	22.0	18.5	0.13
*2	2.6	3.5	0.10	0.0	0.4	0.10
*4	0.9	0.9	0.98	2.4	2.5	0.92
*9	5.7	6.5	0.32	6.5	8.4	0.18
*12	2.3	2.9	0.21	0.6	0.5	0.88

^aHaplotype names follow official recommendations with the addition of *1A(51A) for clarity.

^bNon-dependent smokers (FTND 0 among European Americans, FTND 0-1 among African Americans).

^cDependent smokers (FTND ≥ 4).

^dP-values refer to the likelihood that differences in minor allele frequencies between dependent and non-dependent smokers is due to chance.