The Inertial Mass of a Body

Inertial mass is created by its interaction with all of the other mass in the universe, right? So basically, if you increased the mass density of the universe two times, you would expect the inertial mass of any given body within that universe to also increase. I'm just thinking that maybe, so wouldn't that mean that that body would have twice as much gravitational field? I'm really not sure. It probably would not because it's all going into this vector potential instead of the scalar potential.