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Table 1 Breast cancer risk factors in the cohort

From: Mammographic density adds accuracy to both the Tyrer-Cuzick and Gail breast cancer risk models in a prospective UK screening cohort

Question

Group

No breast cancer

Breast cancer

OR (95 % CI)

Univariate summarya

Age-adjusted summarya

Age, yr

<52

10,601 (21 %)

123 (18 %)

0.85 (0.69–1.04)

58 (52–64)

 
 

52–64

28,466 (57 %)

387 (56 %)

1.00 (reference)

1.30 (1.14–1.48)

 
 

>64

10,864 (22 %)

187 (27 %)

1.27 (1.06–1.51)

15.9 (P < 0.001)

 

Age at menarche, yr

<12

11,298 (23 %)

168 (24 %)

1.09 (0.89–1.31)

13 (12–14)

 
 

12–13

20,817 (42 %)

285 (41 %)

1.00 (reference)

0.99 (0.90–1.08)

0.99 (0.90–1.08)

 

14+

16,685 (33 %)

230 (33 %)

1.01 (0.84–1.20)

0.1 (P = 0.78)

0.1 (P = 0.77)

 

Missing

1131 (2 %)

14 (2 %)

0.90 (0.50–1.49)

  

Parous

Yes

43,578 (87 %)

591 (85 %)

1.00 (reference)

  
 

No

6166 (12 %)

103 (15 %)

1.23 (0.99–1.51)

1.23 (0.99–1.51)

1.28 (1.03–1.58)

 

Missing

187 (0 %)

3 (0 %)

1.18 (0.29–3.12)

3.6 (P = 0.059)

5.0 (P = 0.026)

Age at birth of first child, yr

<21

11,134 (26 %)

139 (24 %)

0.91 (0.74–1.11)

24 (20–27)

 
 

21–27

21,791 (50 %)

300 (51 %)

1.00 (reference)

1.09 (0.98–1.22)

1.13 (1.01–1.26)

 

>27

10,502 (24 %)

150 (25 %)

1.04 (0.85–1.26)

2.4 (P = 0.12)

4.4 (P = 0.037)

 

Missing

151 (0 %)

2 (0 %)

0.96 (0.16–3.03)

  

Age at menopause, yr

<46

16,201 (47 %)

242 (47 %)

0.73 (0.56–0.93)

50 (45–51)

 
 

46–52

7933 (23 %)

86 (17 %)

1.00 (reference)

1.30 (1.16–1.46)

1.28 (1.14–1.44)

 

>52

4906 (14 %)

90 (18 %)

1.23 (0.96–1.56)

21.4 (P < 0.001)

18.4 (P < 0.001)

 

Missing

5321 (15 %)

95 (19 %)

1.20 (0.94–1.51)

  

BMI, kg/m2

<25

17,538 (35 %)

216 (31 %)

1.00 (reference)

26.5 (23.7–30.4)

 
 

25–30

16,633 (33 %)

241 (35 %)

1.18 (0.98–1.42)

1.10 (1.01–1.21)

1.11 (1.01–1.21)

 

30+

12,442 (25 %)

192 (28 %)

1.25 (1.03–1.52)

4.6 (P = 0.033)

4.8 (P = 0.028)

 

Missing

3318 (7 %)

48 (7 %)

1.17 (0.85–1.59)

  

BMI premenopause, kg/m2

<25

1710 (38 %)

18 (31 %)

1.00 (reference)

26.2 (23.3–30.1)

 
 

25–30

1394 (31 %)

24 (41 %)

1.64 (0.89–3.07)

0.98 (0.71–1.33)

0.98 (0.70–1.32)

 

30+

1087 (24 %)

14 (24 %)

1.22 (0.60–2.46)

0.0 (P = 0.92)

0.0 (P = 0.88)

 

Missing

322 (7 %)

3 (5 %)

0.89 (0.21–2.63)

  

BMI perimenopause, kg/m2

<25

3176 (36 %)

33 (34 %)

1.00 (reference)

26.4 (23.5–30.3)

 
 

25–30

2816 (32 %)

33 (34 %)

1.13 (0.69–1.84)

1.00 (0.77–1.27)

1.00 (0.77–1.27)

 

30+

2151 (25 %)

25 (26 %)

1.12 (0.66–1.88)

0.0 (P = 0.99)

0.0 (P = 0.99)

 

Missing

601 (7 %)

7 (7 %)

1.12 (0.45–2.40)

  

BMI postmenopause, kg/m2

<25

11,918 (35 %)

157 (31 %)

1.00 (reference)

26.5 (23.8–30.4)

 
 

25–30

11,767 (34 %)

176 (34 %)

1.14 (0.91–1.41)

1.13 (1.02–1.25)

1.14 (1.02–1.26)

 

30+

8603 (25 %)

144 (28 %)

1.27 (1.01–1.60)

5.2 (P =0.023)

5.5 (P = 0.019)

 

Missing

2073 (6 %)

36 (7 %)

1.32 (0.90–1.88)

  

First-degree relatives with breast cancer

0

44,269 (89 %)

595 (85 %)

1.00 (reference)

  
 

1

5257 (11 %)

92 (13 %)

1.30 (1.04–1.62)

1.32 (1.09–1.58)

1.30 (1.07–1.56)

 

2+

405 (1 %)

10 (1 %)

1.84 (0.91–3.27)

7.8 (P =0.005)

7.0 (P = 0.008)

Biopsies

No

41,311 (83 %)

530 (76 %)

1.00 (reference)

  
 

Yes

7174 (14 %)

136 (20 %)

1.48 (1.22–1.78)

1.48 (1.22–1.78)

1.45 (1.19–1.75)

 

Missing

14,46 (3 %)

31 (4 %)

1.67 (1.14–2.37)

15.0 (P < 0.001)

13.6 (P <0.001)

Current HRT by age group, yr, yes/no

<58, no

23,758 (48 %)

286 (41 %)

1.00 (reference)

  
 

<58, yes

2529 (5 %)

29 (4 %)

0.95 (0.64–1.37)

1.12 (0.82–1.49)

1.43 (1.03–1.95)

 

58+, no

22,328 (45 %)

354 (51 %)

1.32 (1.13–1.54)

0.5 (P = 0.47)

4.7 (P = 0.031)

 

58+, yes

1316 (3 %)

28 (4 %)

1.77 (1.17–2.57)

  
  1. HRT hormone replacement therapy, BMI body mass index, OR odds ratio, CI confidence interval
  2. aSummary, first row: median [interquartile rage (IQR)], second row: IQR odds ratio (95 % confidence interval), third row: likelihood ratio χ2 (P-value)