Stratifying by BMI at blood collection (pint ≤ 0.04 in models for OPG among all cases and ER+ cases) showed that pre-diagnosis OPG concentrations were not associated with risk of death after a breast cancer diagnosis in those with a high BMI (≥ 25 kg/m2) at blood collection (Additional file 1: Table S1). The gene discussed is ESR1; the disease is breast carcinoma.