Subgroup

N

BRCA1/2 cases versus population-based cases

BRCA1/2 cases versus hospital-based cases

Unadjusted

Adjusted1

Unadjusted

Adjusted1

OR (95%-CI)

OR (95%-CI)

OR (95%-CI)

OR (95%-CI)

Cases stratified by tumour diameter

BRCA 1

≤2 cm

171

1.7 (1.2 - 2.3)

1.6 (1.2 - 2.3)*

2.7 (1.9 - 3.7)

2.9 (2.0 - 4.2)*

>2 cm

156

0.7 (0.5 - 0.9)

0.8 (0.6 - 1.1)

0.9 (0.6 - 1.2)

1.5 (1.0 - 2.2)*

BRCA 2

≤2 cm

51

2.0 (1.1 - 3.4)

1.9 (1.1 - 3.3)*

3.1 (1.8 - 5.5)

3.1 (1.7 - 5.6)*

>2 cm

47

1.2 (0.6 - 2.1)

1.3 (0.7 - 2.4)

1.5 (0.8 - 2.7)

1.9 (1.0 - 3.7)

Cases stratified by age at breast cancer diagnosis

BRCA 1

<35

107

0.8 (0.5 - 1.3)

0.8 (0.5 - 1.4)

1.0 (0.7 - 1.6)

1.4 (0.8 - 2.4)

35 - 52

205

1.4 (1.1 - 1.9)

1.5 (1.1 - 2.0)*

1.8 (1.4 - 2.4)

2.5 (1.8 - 3.5)*

>52

42

1.3 (0.7 - 2.4)

1.2 (0.6 - 2.3)

1.6 (0.9 - 2.9)

1.8 (0.9 - 3.7)

BRCA 2

<35

16

1.0 (0.4 - 2.8)

1.0 (0.3 - 3.0)

1.3 (0.5 - 3.7)

1.3 (0.4 - 4.1)

35 - 52

76

2.0 (1.3 - 3.2)

1.9 (1.1 - 3.1)*

2.6 (1.6 - 4.1)

2.6 (1.5 - 4.4)*

>52

20

2.3 (0.9 - 5.6)

2.4 (0.9 - 6.8)

2.7 (1.1 - 6.7)

4.4 (1.5 -12.9)*

Cases stratified by age at breast cancer diagnosis and tumour diameter

BRCA 1(only grade 3 tumours included

<35

≤2 cm

27

2.1 (0.8 - 5.9)

x2

1.8 (0.7 - 4.9)

x2

>2 cm

34

0.4 (0.2 - 0.9)

0.5 (0.2 - 1.4)

0.7 (0.3 - 1.7)

1.4 (0.5 - 4.0)

35 - 52

≤2 cm

63

2.5 (1.5 - 4.4)

2.8 (1.6 - 4.8)*

3.5 (2.0 - 6.2)

5.1 (2.7 - 9.8)*

>2 cm

54

1.2 (0.7 - 2.1)

1.5 (0.8 - 2.6)

1.1 (0.6 - 2.0)

1.9 (1.0 - 3.7)

>52

≤2 cm

11

0.6 (0.1 - 2.7)

0.6 (0.1 - 2.9)

0.6 (0.1 - 2.7)

0.9 (0.1 - 5.0)

>2 cm

12

0.8 (0.2 - 2.4)

0.9 (0.3 - 2.9)

0.9 (0.3 - 2.8)

2.4 (0.6 - 9.3)

BRCA 22

Cases stratified by year of diagnosis and tumour diameter

BRCA 1 (only grade 3 tumours included

≤1995

≤2 cm

53

0.8 (0.4 - 1.6)

x2

0.9 (0.4 - 1.7)

x2

>2 cm

37

0.5 (0.3 - 1.1)

0.8 (0.4 - 1.8)

1.0 (0.5 - 1.9)

2.4 (1.1 - 5.3)*

>1995

≤2 cm

48

5.7 (3.0 - 10.7)

5.8 (3.0 - 11.2)*

6.5 (3.4 - 12.6)

10.3 (4.8 - 22.3)*

>2 cm

63

1.0 (0.6 - 1.8)

1.0 (0.6 - 1.8)

0.9 (0.5 - 1.6)

1.5 (0.8 - 2.8)

BRCA 22