Most studies show women with high bone density have about twice the risk of breast cancer of women with low bone density [120-125]. However, not all studies show this link .
Why might high bone density increase breast cancer risk?
Having strong bones does not increase breast cancer risk. Rather, high bone density is a marker for higher levels of estrogen in the body (the more estrogen a woman produces in her lifetime, the more bone mass she has). These higher estrogen levels are linked to an increased breast cancer risk.
Learn more about estrogen and breast cancer risk.
Bone density and osteoporosis
Although women with higher bone density appear to have a higher risk of breast cancer, they have a lower risk of osteoporosis .