Table 1 Risk factors and clinical characteristics of cases and controls. Cases are also shown stratified by tumor size

Age, median (Q1, Q3)*

61.0 (53, 70)

61.1 (53, 71)

60.0 (52, 69)

57.7 (50, 67)

61.4 (54, 70)

Body mass index, median (Q1, Q3)*

25.8 (22.7, 30.5)

25.8 (22.8, 30.3)

26.4 (22.5, 30.8)

28.6 (24.4, 32.9)

25.8 (22.9, 30.2)

 White

943 (81.3%)

706 (82.1%)

193 (79.4%)

32 (88.9%)

2028 (85.9%)

 Asian

139 (12.0%)

95 (11.0%)

37 (15.2%)

2 (5.6%)

203 (8.6%)

 African-American

26 (2.2%)

18 (2.1%)

6 (2.5%)

0 (0.0%)

39 (1.7%)

 Hispanic

21 (1.8%)

17 (2.0%)

3 (1.2%)

0 (0.0%)

43 (1.8%)

 Others/mixed

31 (2.7%)

24 (2.8%)

4 (1.6%)

2 (5.6%)

47 (2.0%)

Interval between mammograms, median (Q1, Q3)

3.0 (1.9, 3.9)

3.0 (1.9, 4.0)

3.0 (1.9, 3.9)

2.9 (1.6, 3.9)

3.1 (2.0, 4.1)

First degree family Hx B.C.*

317 (27.6%)

247 (29.1%)

59 (24.5%)

6 (16.7%)

479 (20.4%)

Post-menopausal* (age 55+)

805 (69.4%)

605 (70.3%)

161 (66.3%)

21 (58.3%)

1675 (71.0%)

Screening mammogram within 2 months of diagnosis

1043 (90%)

784 (91%)

212 (87%)

27 (75%)

–

 a

132 (12.9%)

107 (14.1%)

20 (9.5%)

3 (10.0%)

463 (20.5%)

 b

408 (40.0%)

309 (40.6%)

81 (38.6%)

9 (30.0%)

973 (43.1%)

 c

391 (38.3%)

275 (36.1%)

94 (44.8%)

17 (56.7%)

684 (30.3%)

 d

89 (8.7%)

70 (9.2%)

15 (7.1%)

1 (3.3%)

138 (6.1%)

 Median

6.9

6.6

8.1

9.0

5.9

 Q1, Q3

4.8, 11.3

4.6, 10.8

5.2, 12.9

5.7, 12.8

4.3, 9.7

 Range

(2.3–36.0)

(2.3–36.0)

(2.4–29.7)

(3.3–24.8)

(2.0–36.3)

 Median

56.0

53.5

62.6

81.6

47.7

 Q1, Q3

41.5, 79.4

40.0, 73.5

45.1, 90.4

62.2, 110.7

35.9, 64.8

 Range

(12.4–281.1)

(12.4–265.4)

(17.7–212.6)

(22.2–199.2)

(10.8–314.8)