Link between High Bone Density and Breast Cancer?

Can you answer Heidi14’s question about Osteoporosis?:

Any information about links between high bone density and breast cancer? I recently had my bone density checked for Osteoporosis risk using the heel ultrasound, and was off the charts, up around 4.6. Low risk is usually measured as values between 0-2, but anything above zero is supposed to be good.

Osteoporosis Bone Density