Table 2

Cigarettes smoked daily: Helix Tree 2-loci interaction analysis using single nucleotide polymorphisms (SNPs) in CHRNA4 and CHRNB2 regions^*

Gene name (SNP no.)	Gene name (SNP no.); interaction p values^†

	A4(rs3746372)	A4(rs3787116)	A4(rs4522666)	A4(rs755203)	B2(rs1127309)	B2(rs1127314)
B2(rs1127314)	0.0148	0.0074	0.0066	0.0128	NA	NA
B2(rs1127309)	0.0087	0.0072	0.0069	0.0068	NA	NA
A4(rs755203)	0.0074	0.0072	NA	NA	0.0577	0.1209
A4(rs4522666)	0.0037	0.0013	NA	NA	0.0633	0.0603
A4(rs3787116)	0.0004	NA	0.0112	0.0656	0.0662	0.0674
A4(rs3746372)	NA	0.0026	0.0325	0.0680	0.0618	0.1084

NA = not applicable.
↵* SNP CHRNB2(rs3926124) was not informative and was excluded from the table.
↵† Interaction p value for all possible combinations except for the linked markers; p values above the diagonal are uncorrected, p values below are adjusted for multiple test.