Figure 2

Relationships between cytochrome P450 1A2 (CYP1A2) activity and percentage breast density according to (a) serum and (b) urinary malondialdehyde (MDA) levels, and (c) malondialdehyde–deoxyguanosine (dG-MDA) levels. All analyses are adjusted for age, ethnicity, body mass index (BMI), waist–hip ratio (WHR), and smoking status. Confounders were set at mean values and determined for Caucasian nonsmokers to illustrate relationships between CYP1A2 activity and percentage density according to MDA levels. Number of women in each group: premenopausal, n = 146 for serum MDA and n = 141 for urinary MDA and dG-MDA; and postmenopausal, n = 149 for serum and urinary MDA and n = 145 for dG-MDA. CMR, caffeine metabolic ratio.