Table 1.

Characteristics of breast cancer cases and controls in the BWHS

CharacteristicCases (n = 1199)Controls (n = 1948)
Mean age, y4747
Region of residence, %
 Northeast2725
 South3131
 Midwest2525
 West1718
US born, %97.797.5
First-degree family history of breast cancer, %13.48.2
Global percent African ancestry, %80.680.5