Abstract
Although a current decline in breast cancer incidence and mortality is being observed, the disease continues to be the most common malignancy among women. Breast cancer is a worldwide public health problem that causes substantial personal and social burdens. While we do not yet know exactly what causes the disease, we know a large number of risk factors that are linked to breast cancer. In particular, hormonal factors seem to play a key role in the causation of the disease. The aim of this paper is to review the current knowledge of established and suspected risk factors of breast cancer from an epidemiologic point of view.