Family history of Breast Cancer
If you one first-degree female relative (sister, mother, daughter) diagnosed with breast cancer, your risk is doubled. If two first-degree relatives have been diagnosed, your risk is 5 times higher than average.
In general, the younger the relative was when she was diagnosed, the greater a woman’s chance of getting breast cancer.
A woman whose mother was diagnosed with breast cancer before age 40 has about twice the risk of a woman without a family history.
Breast density
Women with high breast density are four to five times more likely to get breast cancer than women with low breast density. Dense breasts have less fatty tissue and more non-fatty tissue compared to breasts that aren’t dense. Dense breasts have more gland tissue that makes and drains milk and supportive tissue (also called stroma) that surrounds the gland.
Breast density can be inherited, so if your mother has dense breasts, it’s likely you will, too. Dense breasts have more gland tissue that makes and drains milk and supportive tissue ( also called stroma ) that surrounds the gland. Breast density can be inherited, so if your mother has dense breasts, it’s likely you will, too.
Age of first menstrual period
Women who started menstruating (having periods) younger than age 12 have a higher risk of breast cancer later in life. Over the past 15 years, girls have been starting puberty at younger ages. Breast development has started even earlier than menstrual periods. This unexpected shift has been attributed to the obesity epidemic and broad exposure to hormone disruptors, since a rise in hormones triggers the onset of breast development and puberty.
The levels of the female hormone estrogen change with the menstrual cycle. Women who start menstruating at a very young age have a slight increase in breast cancer risk that may be linked to their longer lifetime exposure to estrogen