TABLE 4.

Adjusted hazard ratios (95% CIs) for menopause by baseline heaviness of smoking, stratified by genotype in European Americans

SNP	n	Light smokers vs nonsmokersa	P	n	Heavy smokers vs nonsmokersa	P
CYP1B1*3−/−	15	0.81 (0.33–2.01)	0.66	8	0.83 (0.28–2.45)	0.74
CYP1B1*3+/− and CYP1B1*3+/+	25	1.92 (1.08–3.42)	0.03 (Pint = 0.04b)	17	3.0 (1.54–5.84)	0.001
CYP3A4*1B−/−	39	1.61 (0.98–2.66)	0.06	21	1.54 (0.82–2.9)	0.18
CYP3A4*1B+/− and CYP3A4*1B+/+	22	11.73 (1.27–107.91)	0.03 (Pint = 0.04b)	2	17.79 (3.21–98.65)	0.001

Hazard ratios were adjusted for baseline age and educational attainment.

SNP, single nucleotide polymorphism.

^aAdjusted hazard ratios for menopause in smokers by genotype status (carrier vs noncarrier).

^bP value for the interaction of heaviness of smoking and genotype status on risk of menopause.