Breast cancer is the most common cancer in women worldwide and the second leading cause of cancer-related death in women (lung cancer is first). In the United States (US), a woman’s chance of contracting breast cancer is one in eight.
Risk factors that increase the risk for development of breast cancer include:
- Gender: Female have an increased risk, but does occur in men.
- Age: Risk increases with aging, peaking at 75-80 years.
- Menstrual history: An early menarche (before age 12) or late menopause (after age 55) both increase risk.
- Reproductive history: No full-term pregnancy or a late pregnancy (after age 30) increases risk.
- Personal and family history: Having first degree relatives with breast cancer increases risk. Inherited mutations (eg, BRCA1 and BRCA2) increase risk.
- Race and ethnicity: In the US, non-Hispanic, white women are at increased risk.
- Body weight: Obesity increases the risk in postmenopausal women.
- Lifestyle-related factors: Lack of regular physical activity, alcohol consumption (more than one drink per day), postmenopausal hormone use (combined estrogen and progestin), and tobacco use all increase risk.