I had a Dexa scan 10 or so years ago. Yep, low bone density, like most cyclists, even though I weight train, backpack, ski, etc. OTOH, I've never broken a bone. I took Alendronate for 5 years, the limit, but it didn't do much, if anything. The doc didn't mention muscle or fat mass, guess it wasn't interesting to her. I have one of those scales which measures bone, fat, and muscle percentages. I use it every morning when I get up. It's interesting. Everything varies except bone mass.