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Table 1 Selected characteristics of study subjects by ethnicity and menopausal status

From: Cytochrome P450 1A2 (CYP1A2) activity, mammographic density, and oxidative stress: a cross-sectional study

  With CYP1A2 results No CYP1A2 results5
  Caucasian1: pre (n = 125); post (n = 126) East Asian2: pre (n = 4); post (n = 6) Jewish3: pre (n = 10); post (n = 5) Other4: pre (n = 7); post (n = 12) Pre (n = 36); post (n = 26)
Premenopausal      
   Risk factors      
Age (years) 44.8 (4.8) 46.8 (4.5) 45.4 (3.1) 44.7 (5.1) 45.1 (4.4)
Weight (kg) 68.1 (16.6) 54.8 (3.1) 59.4 (10.7) 64.9 (17.9) 69.1 (13.3)
BMI (kg/m2) 25.3 (6.1) 23.2 (0.9) 22.6 (3.5) 25.9 (6.5) 25.8 (5.1)
WHR 0.75 (0.06) 0.75 (0.04) 0.73 (0.07) 0.77 (0.05) 0.74 (0.06)
Age at menarche (years) 12.8 (1.5) 11.5 (1.3) 12.2 (0.6) 13.7 (1.6) 12.6 (1.5)
Age at first birth (years) 27.8 (5.7) 29.5 (0.7) 29.5 (2.7) 25.6 (9.7) 29.0 (6.4)
Number of live births 1.4 (1.2) 1.0 (1.2) 2.1 (1.3) 1.6 (1.3) 1.5 (1.2)
Mammographic density (%)6 27.4 (23.2) 47.6 (17.0) 40.2 (22.7) 25.9 (20.0) 28.4 (20.5)
CYP1A2 activity7 6.31 (2.95) 6.52 (0.98) 4.98 (1.04) 6.11 (3.50) -
   Markers of oxidative stress      
Serum MDA (μmol/l) 1.47 (0.58) 1.52 (0.47) 1.53 (1.05) 1.77 (0.68) 1.45 (0.66)
Urinary MDA (μmol/day) 2855.3 (1514.1) 3591.6 (1365.9) 2813.0 (1392.2) 2293.9 (1116.9) 3729.4 (1365.9)
dG-MDA (ρmol/mg DNA) 200.8 (157.9) 232.8 (115.7) 221.4 (164.6) 169.31 (76.27) 180.2 (135)
Postmenopausal      
   Risk factors      
Age (years) 56.3 (4.6) 54.8 (3.8) 53.4 (2.5) 55.9 (4.2) 56.0 (4.5)
Weight (kg) 72.5 (16.6) 55.8 (9.8) 70.5 (18.1) 66.6 (15.7) 63.7 (17.0)
BMI (kg/m2) 26.8 (6.2) 23.2 (4.7) 25.9 (6.8) 25.6 (5.4) 23.3 (5.2)
WHR 0.77 (0.07) 0.77 (0.08) 0.80 (0.09) 0.80 (0.06) 0.75 (0.11)
Age at menarche (years) 13.1 (1.6) 13.0 (1.7) 12.6 (2.6) 13.0 (2.1) 12.8 (1.70)
Age at menopause (years) 49.1 (4.8) 50.8 (3.3) 49.1 (3.7) 48.8 (2.5) 48.2 (4.3)
Age at first birth (years) 26.0 (5.2) 34.6 (6.8) 22.8 (3.8) 31.0 (8.7) 25.4 (4.1)
Number of live births 1.8 (1.5) 1.8 (1.5) 2.2 (1.6) 1.0 (1.0) 1.4 (1.4)
Mammographic density (%)6 19.8 (18.5) 48.2 (8.9) 22.3 (24.6) 30.1 (23.8) 36.0 (22.1)
CYP1A2 activity7 5.73 (2.18) 8.86 (1.83) 3.49 (1.75) 6.64 (2.81) -
   Markers of oxidative stress      
Serum MDA (μmol/l) 1.75 (0.65) 1.83 (0.59) 1.69 (0.74) 1.64 (0.7) 1.84 (0.72)
Urinary MDA (μmol/day) 3518.5 (1587.5) 4636.2 (1348.3) 3412.9 (978.9) 3717.0 (1926.2) 2449.3 (1301.8)
dG-MDA (ρmol/mg DNA) 197.7 (112.6) 149.9 (107.2) 158.2 (108.1) 212.9 (80.8) 203.2 (109.6)
  1. Values are expressed as mean (standard deviation). 1Premenopausal (pre): n = 86 for age at first birth, n = 120 for urinary malondialdehyde (MDA), and n = 121 for malondialdehyde–deoxyguanosine (dG-MDA). Postmenopausal (post): n = 117 for menopausal age, n = 97 for age at first birth, and n = 123 for dG-MDA. 2Pre: n = 2 for age at first birth. Post: n = 5 for age at first birth. 3Pre: n = 8 for age at first birth and n = 9 for dG-MDA. Post: n = 4 for age at first birth and dG-MDA. 4Pre: n = 5 for age at first birth. Post: n = 11 for menopausal age and n = 8 for age at first birth. 5Pre: n = 25 for age at first birth, n = 7 for urinary MDA, and n = 34 for dG-MDA. Post: n = 23 for age at menopause, n = 14 for age at first birth, n = 15 for urinary MDA, and n = 25 for dG-MDA. 6Proportion of breast area occupied by dense tissue. 7Estimated by caffeine metabolic ratio (see text for details). BMI, body mass index; CYP1A2, cytochrome P450 1A2; WHR, waist–hip ratio.