Family History Exposure	Family History of Women Included1
No family history	No relatives with a positive history of breast cancer (Referent group for all analyses)
1st degree family history
1st degree history only	≥ 1 affected first-degree relatives, no affected second- degree relatives
1st and 2nd degree history	≥ 1 affected first AND second-degree relatives
Number of affected 1st degree relatives
1	1 affected first-degree relative, regardless of second-degree history
≥ 2	≥ 2 affected first-degree relatives, regardless of second-degree history
Age of affected 1st degree relatives
≥ 50 years only	≥ 1 affected first-degree relative diagnosed ≥ 50 years, none diagnosed < 50 years, regardless of second-degree history
At least one <50 years	≥ 1 affected first-degree relative diagnosed < 50 years, regardless of second-degree history
2nd degree family history
2nd degree history only	≥ 1 affected second-degree relative, no affected first-degree relatives
Number of affected 2nd degree relatives
1	1 affected second-degree relative, no affected first-degree relatives
≥ 2	≥ 2 affected second-degree relatives, no affected first-degree relatives
Age of affected 2nd degree relatives
≥ 50 years only	≥ 1 affected second-degree relative diagnosed ≥ 50 years, none diagnosed < 50 years, and no first-degree history
At least one <50 years	≥ 1 affected second-degree relative diagnosed < 50 years and no first-degree history
Specific Relative History2
Number of affected relatives
1	1 affected specific relative
≥ 2	≥ 2 affected specific relatives
Number of affected relatives and age at diagnosis
Only affected ≥ 50 years
1	1 relative diagnosed ≥ 50 years, none diagnosed < 50 years
≥ 2	≥ 2 relatives diagnosed ≥ 50 years, none diagnosed < 50 years
≥ 1 relative < 50 years	At least 1 relative diagnosed < 50 years

¹In only female relatives: mother, sister(s), aunt(s), daughter(s)

²For grandmother, sister, and aunt history