Through daily practise of tai chi and chi kung, as well as taking vitamin D and calcium supplements (if your diet is low in these), you can lessen your loss in bone density. The Harvard Medical School Guide to Tai Chi quotes research in this, with facts and figures...

A good basic exercise is to stand with your feet apart, knees bent, and arms as if holding a giant dinosaur egg. Do this every day, starting with as little time as you like - gradually increasing the time, as your legs and arms become stronger. You will start to feel the difference fairly soon.

Another problem people have is falls due to lack of balance. If you have osteoporosis, you really need to learn balance, in order to avoid bone breakage - and balance is good for everyone!

People's problems with balance usually come either from poor posture, or from being unaware of where their weight is:

Your instructor will show you how to correct your posture over time - habits are hard to break, even when you become aware of them, so you need someone to correct you regularly, until you have ingrained the new posture habit into your body memory.

Your instructor will also teach you tai chi walking, which looks and feels extremely peculiar at first, but it will help you become very aware of where your weight is and how to change this in a healthy way, maintaining good posture. This is worth doing every day, for everyone from beginners right up to top level people, as it is so very good for balance and posture, for health reasons as well as for self-defence reasons.

You can learn tai chi without ever learning the self-defence side of it (many clients prefer this), but knowing what the self-defence application is, will help you achieve correct posture in each movement, which is part of what makes tai chi so good for maintaining and improving health.