Fig. 1

Study design and data collection. a Data were collected at three timepoints. Baseline blood samples were collected between 1992 and 2000. Breast cancer cases were diagnosed between baseline and initiation of the case-control study in 2006, and tumor characteristics at the time of breast cancer diagnosis were collected. Participants were followed-up for mortality from the time of breast cancer diagnosis to 2015. b 2020 breast cancer cases were initially selected for the case-control study. Of these, 1970 cases had complete information on sRANKL concentrations and follow-up for mortality, and 2006 had complete information on OPG concentrations and follow-up