Among females worldwide, breast cancer is the most frequently diagnosed cancer, accounting for 25% of all new diagnoses in 2012, and is the leading cause of cancer mortality (15% of total cancer deaths), particularly among less developed nations. Incidence rates of breast cancer are generally higher in Northern America, Australia/New Zealand, and Northern and Western Europe, and lower in most African and Asian countries. Factors associated with this international variation in incidence include those related to early detection, particularly the availability of mammography screening, as well as the prevalence of established risk factors, including overweight/obesity, use of menopausal hormone therapy, physical inactivity, and alcohol consumption.