Table 1 Baseline characteristics of nested case-control participants by breast cancer status (n = 236), all other participants in the full unaffected cohort (n = 1729), New York Site of the BCFR

Age at blood draw

 Mean years (s.d.)

46.2 (10.3)

45.5 (10.9)

45.8 (10.7)

42.8 (13.2)^b

Ethnicity

 Non-Hispanic White

71 (88.8)

134 (85.9)

205 (86.9)

1136 (65.7)

 Hispanic

9 (11.3)

20 (12.8)

29 (12.3)

414 (23.9)

 Others

0 (0)

2 (1.3)

2 (0.9)

179 (10.4)

BMI

 Mean kg/m² (s.d.)

24.6 (4.5)

23.8 (4.4)

24.1 (4.4)

25.2 (5.6)

Menopausal status

 Pre-menopausal

52 (65.0)

112 (71.8)

164 (71.9)

1129 (67.0)

 Post-menopausal

27 (33.8)

37 (23.7)

64 (28.1)

557 (33.0)

Smoking status

 Current

6 (7.5)

14 (9.0)

20 (8.5)

153 (8.9)

 Former

29 (36.3)

44 (28.2)

73 (31.1)

513 (29.8)

 Never

44 (55.0)

98 (62.8)

142 (60.4)

1054 (61.3)

Alcohol consumption

 Current

27 (33.8)

58 (37.2)

85 (36.5)

505 (29.4)

 Former

17 (21.3)

24 (15.4)

41 (17.6)

505 (16.7)

 Never

36 (45.0)

71 (45.5)

107 (45.9)

943 (54.9)

BOADICEA score

 Mean (s.d.)

7.94 (7.2)

5.55 (5.0)

6.76 (6.84)

4.88 (6.1)

 Average risk (< 3.4%)

19 (23.8)

56 (35.9)

75 (32.5)

841 (48.6)

 Elevated risk (≥ 3.4%)

61 (76.3)

95 (60.9)

156 (67.5)

888 (51.4)

IGF-1 level (ng/mL)

 Geometric mean (geometric s.d.)

95.0 (1.46)

93.9 (1.45)

94.3 (1.45)

N/A

 Median (IQR)

99.6 (45.6)

94.0 (45.8)

96.4 (45.9)

N/A

 < 93.95

34 (42.5)

78 (50.0)

112 (47.5)

N/A

 Elevated (≥ 93.95)^a

46 (57.5)

78 (50.0)

124 (52.5)

N/A

IGFBP-3 level (ng/mL)

 Geometric mean (geometric s.d.)

2069.3 (1.25)

1960.3 (1.32)

1996.6 (1.30)

N/A

 Median (IQR)

2097 (635)

2009 (652)

2057 (638)

N/A

 < 2009

34 (42.5)

78 (50.0)

112 (47.5)

N/A

 Elevated (≥ 2009)^a

46 (57.5)

78 (50.0)

124 (52.5)

N/A