I found a website about osteopenia interesting. The site was started by an academic who found herself dealing with bone density loss and approachef it like ant other research project. The site is free and she says that she and others have in fact slowed down or reversed bone loss. She suggests starting with the page addressing causes of loss of bone and work through the information on what seems to work to reverse or slow that down. As always, don't accept everything as a permanent truth since science is still working on how to do this, but it's a good overview. And she mentions some things that are frequently over looked like proton pump inhibitors which several studies link to bone loss. The website URL is below:

osteopenia3.com