^*The Breast Cancer Risk Assessment Tool (i.e., the Gail model) is used to predict risk of invasive breast cancer in women 35 years of age or older. Gail model variables are all from baseline, and include age, ethnicity, age at menarche, age of the mother at the birth of her first live child, number of first-degree relatives with breast cancer, and the number of previous breast biopsy examinations. Because historical information on atypical hyperplasia was not collected in WHI, all women with previous breast biopsy examinations are coded as “unknown” for this variable. Please see the WHI Data Preparation document for more detail and a reference.