Hi verdungal, welcome and thanks for your question.  I've never heard of vitamin E being capable of preventing osteoporosis.  I suppose it can't hurt since we need E for other things but I wouldn't count on it for prevention purposes.

Have you discussed this with your Dr?  I would ask if there are any studies on bone loss or prevention of bone loss with the use of vitamin E.

Calcium, D3, vitamin k, and magnesium are all good bone health products, but I don't think that they can prevent it.  These supplements will help a lot and hopefully slow bone loss but expecting them to prevent bone loss entirely seems unlikely.  Don't forget to get the recommended weight bearing exercises, since they are important as well.  The National Osteoporosis Foundation recommends 2 1/2 hours a week "or more" for osteopenia and osteoporosis.

Good luck...