Detailed description of GWA study subjects in the NHS and the WGHS are available in the Supplementary Methods online. Briefly, the 2,287 NHS participants included in the present analysis were from the nested breast cancer case-control study in the NHS subcohort with blood sample collection between 1989-1990. The 15,151 women in the WGHS are participants in the ongoing Women’s Health Study (WHS) and provided a blood sample in 1993. The Institutional Review Board of Brigham and Women’s Hospital approved these studies.
