This seems to happen when our colons are compromised so we aren't absorbing our calcium and magnesium over a period of quite a few years. Part of what happens as we age. Reversible, though.
Interesting article to me. Tony Pantalleresco speaks about the use of sodium thiosulfate and puts a lot of faith in what it can do. Look him up on you tube, if you're interested. He's got a good presentation on the use of it, too.