Table 4.

Association of global percent African ancestry with breast cancer subtypes in the BWHS

Quintile of % African ancestryER+/PR+ casesER−/PR− casesTriple negative cases
(median in ER+/PR+)NNORa (95% CI)NORa (95% CI)
1 (64.8)73371.00 (ref)121.00 (ref)
2 (76.6)61451.47 (0.84–2.60)90.92 (0.37–2.25)
3 (82.3)78551.41 (0.82–2.43)191.57 (0.73–3.37)
4 (87.5)73401.09 (0.62–1.91)161.20 (0.53–2.68)
5 (92.4)51522.08 (1.16–3.71)253.04 (1.41–6.58)
Mean % African ancestry79.981.6P = 0.0583.0P = 0.008
  • aORs adjusted for age, geographic region of residence, and country of birth.