Table 2.

Allele frequency of the CYP1A2*1F mutation in Intron 1 from our study and from other published studies.

Study	Number of subjects	*1 A (Wt) (95% C.I.)	*1F (95% C.I.)
Present study	1170	0.29 (0.27, 0.31)	0.71 (0.69, 0.73)
Sachse et al. [18]	236	0.32 (0.28, 0.36)	0.68 (0.64, 0.72)
Christiansen et al. [32]	60*	0.32 (0.23, 0.40)	0.68 (0.60, 0.77)
Basile et al. [30]	85	0.38 (0.31, 0.45)	0.62 (0.55, 0.69)
Han et al. [28]	168	0.33 (0.28, 0.38)	0.67 (0.62, 0.72)

^*Only the controls are shown.