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Table 1 Mammographic density measurements by known breast cancer risk factors, mammographic projection, and case status at time of mammography

From: A comprehensive evaluation of interaction between genetic variants and use of menopausal hormone therapy on mammographic density

Characteristic Number (%) PD, mean (95 % CI)a,b Dense area, cm2, mean (95 % CI)a,b Non-dense area, cm2, mean (95 % CI)a,b
Total 6,298 (100.0) 18.1 28.5 143.1
Age, years     
<50 190 (3.0) 25.9 (23.8, 28.0) 32.9 (29.8, 36.1) 98.4 (92.4, 104.5)
≥50 to <60 1,948 (30.9) 21.3 (20.4, 22.2) 30.8 (29.4, 32.3) 114.9 (111.8, 118.0)
≥60 to <70 2,939 (46.7) 17.6 (16.8, 18.4) 27.0 (25.7, 28.3) 127.9 (124.7, 131.0)
≥70 to <80 1,101 (17.5) 16.7 (15.7, 17.7) 25.8 (24.2, 27.5) 131.9 (128.0, 136.0)
≥80 120 (1.9) 14.3 (12.3, 16.4) 22.1 (18.9, 25.5) 135.8 (126.9, 145.0)
BMI, kg/m2     
<25 2,488 (39.5) 25.0 (24.0, 25.9) 30.0 (28.7, 31.4) 85.9 (83.3, 88.5)
≥25 to <30 2,244 (35.6) 17.6 (16.8, 18.4) 27.9 (26.6, 29.3) 129.0 (125.7, 132.4)
≥30 to <35 1,088 (17.3) 13.3 (12.4, 14.1) 25.5 (24.0, 27.1) 170.0 (165.5, 174.6)
≥35 478 (7.6) 10.2 (9.3, 11.2) 23.0 (21.1, 24.9) 211.3 (204.7, 217.9)
MHT use     
never 2,885 (45.8) 16.2 (15.6, 16.9) 23.7 (22.7, 24.8) 128.3 (125.6, 131.1)
former 2,100 (33.3) 17.5 (16.8, 18.3) 26.0 (24.8, 27.3) 125.7 (122.8, 128.7)
current 1,313 (20.9) 19.9 (19.0, 20.8) 29.7 (28.2, 31.2) 121.5 (118.2, 124.9)
Parity     
nulliparous 775 (12.3) 22.3 (21.1, 23.5) 32.7 (30.9, 34.6) 117.5 (113.6, 121.4)
1 full-term pregnancy 848 (13.5) 20.2 (19.1, 21.3) 31.0 (29.2, 32.9) 124.0 (120.0, 128.0)
2 full-term pregnancies 2,369 (37.6) 18.3 (17.5, 19.1) 27.5 (26.2, 28.9) 126.2 (123.1, 129.4)
≥3 full-term pregnancies 2,306 (36.6) 17.2 (16.5, 18.0) 25.3 (24.0, 26.6) 123.2 (120.2, 126.3)
Mammographic viewc     
MLO 3,454 (54.8) 14.6 (14.1, 15.1) 23.3 (22.4, 24.2) 139.3 (137.1, 141.6)
CC 2,844 (45.2) 19.0 (18.5, 19.5) 29.0 (28.1, 30.0) 122.6 (120.7, 124.6)
Case status     
non-case 4,054 (64.4) 17.0 (16.2, 17.8) 25.7 (24.5, 27.0) 128.4 (125.3, 131.6)
case 2,244 (35.6) 20.4 (19.6, 21.3) 30.0 (28.7, 31.4) 118.9 (116.0, 121.8)
  1. aBack-transformed. bAdjusted for study, reference age, use of menopausal hormone therapy (MHT), body mass index (BMI) and number of pregnancies. cIn each study mammographs were taken in either the mediolateral oblique (MLO) or craniocaudal (CC) projection. PD percent density