Hormones
Persistently increased blood levels of estrogen are associated with an increased risk of breast cancer, as are increased levels of the androgens androstenedione and testosterone (which can be directly converted by aromatase to the estrogens estrone and estradiol, respectively). Increased blood levels of progesterone are associated with a decreased risk of breast cancer in premenopausal women. A number of circumstances which increase exposure to endogenous estrogens including not having children, delaying first childbirth, not breastfeeding, early menarche (the first menstrual period) and late menopause are suspected of increasing lifetime risk for developing breast cancer.
However, not only sex hormones, but also insulin levels are positively associated with the risk of breast cancer.
Read more about this topic: Risk Factors For Breast Cancer
Famous quotes containing the word hormones:
“Teenage boys, goaded by their surging hormones ... run in packs like the primal horde. They have only a brief season of exhilarating liberty between control by their mothers and control by their wives.”
—Camille Paglia (b. 1947)