If you're asking for the name of this it would be osteoporosis
An example of a viral STD that's uncurable is HIV.
"breaking a habit" means to stop doing a particular behavior for good.
Habit is a behavior that you constantly do. An example of this is biting your nails when you are nervous.
"Breaking a habit" is to stop biting your nails when you are nervous. Instead you divert your attention into doing something else when you are nervous instead of biting your nails.
