Lifetime risk: The risk of developing a disease during ones lifetime or dying of the disease. The estimated lifetime risk of developing diabetes for individuals born in 2000 in the US is 32.8% for males and 38.5% for females. Women who inherit mutations of the BRCA1 or BRCA2 gene are at an 82% lifetime risk of developing breast cancer. The lifetime risk of dying from prostate cancer is 3.4% for American men. However, the lifetime risk of death for the entire population is 100%.