Is it a place for real "scientific" discussion? There are a lot of research on the subject.

https://americanbonehealth.org/exercise/bonesense-on-osteogenic-loading/

Article The Amazing Osteocyte

Article Mechanical Signaling for Bone Modeling and Remodeling

and so on.

Where is the Scientific reference (not advertisement as Vladimir proposed the reference) that walking only improves bone strength and not muscle and also nothing else in the body. In my opinion, walking improves health in every organ of the body including brain, lungs, heart etc.. Even after recovery from any surgery of any organ, the patients are advised to walk a bit to keep body system moving. Let us hear from others. Thanks for initiating discussion, Shefin

We need to find a paper with data percent of people getting osteoporosis who have been doing exercise in their life as compared to people who do not do,

Sorry but I need to understand clearly the question. Do you mean walking vs muscle strengthening (ex. weight lifting) or improvement of bone vs improvement of muscle?

For bones, as Pascale Royer said, the mechanical loading (mostly through the contraction of muscles and the body weight) is the most important trigger of bone remodeling. And both walking and muscle workout cause this loading. So,

- During space flight, the astronauts loose both muscle strength and pressure of body weight

- Walking causes the trigger mainly on lower extremities

- Many kinds of muscle workouts use body weight (even exercises for arms) so theoretically they affect on whole body bone.