Other Covariables

Demographic factors including age, race and ethnicity, and education were collected using a baseline questionnaire. Where possible, missing data were supplemented with data obtained from the KPNC electronic health records (EHR). Both body mass index (BMI) and comorbid conditions were obtained from the EHR. A weighted Elixhauser comorbidity index score was calculated from inpatient comorbid conditions dating back to the participant’s earliest record.³² Diagnostic and clinical data, including tumor stage, estrogen receptor status (ER), progesterone receptor status (PR), human epidermal growth factor receptor 2 status (HER2), type of surgery, and receipt of chemotherapy, radiation therapy, and hormonal therapy were obtained from the KPNC Cancer Registry and other clinical databases.