Osteopenia doesn't mean you have osteoporosis. It just means that there is thinning detected, and that would be pretty common for a lot of menopausal women. They may not know it though because they haven't had a BMD (bone mineral density) done, and as there are no symptoms felt, unless you have a fracture or a BMD you won't know. Of course it can be a precursor to osteoporosis, but it's not something to panic about yet. If you do have osteopenia, now is the time to take action so it doesn't develop into something more serious.
I was diagnosed with osteopenia probably about 10 years ago, in my late 40s. The standard treatment is Fosamax. Yes, things like exercise, HRT, and supplements can help. I do all that, but I can tell you that, for me, none of that really helped that much. While I was taking Fosamax things were fairly stable, but a naturopath talked me into going off it, and after a couple of years of not being on it, my thinning got worse. What made me decide to return to Fosamax was that Dr Elizabeth Vliet, whose opinion I respect, advocates in her books the taking of Fosamax if you have osteopenia. So I will remain on Fosamax.
I've never had any side effects from taking it. It's only a once a week tablet if you start taking it for osteopenia. There is some scaremongering on the internet about it, but that is more than likely related to people with advanced osteoporosis, who have to take the medication daily. However, what medication doesn't get some kind of scaremongering - think HRT.
btw - I'll just add that there is nothing scary about having a BMD done. It's just a scan. I just wanted to say that, because a friend of mine thought they actually have to remove a piece of bone to test it...lol....
Taz made her post while I was typing mine, so I'll just add something about the supplements. I wouldn't just start taking a whole heap of calcium just because it's something people think you have to take for bone strength. You do need to be careful about how much calcium you take, as the body can only absorb a certain amount at any one time. What it can't absorb is often stored in the body in places you don't want it stored. So I would go with whatever suggestions and doses your doctor recommends.