The question has come up in the past about how/whether or not corticosteroids affect bone density.  From the same article:

"Corticosteroids adversely alter skeletal metabolism through multiple pathways, such as inhibition of intestinal calcium absorption (13), increased osteoclast-mediated bone resorption (15), direct stimulation of renal excretion of calcium (15), and the direct suppression of bone formation (16)....."

Sounds to be pretty black and white, huh?  From another website, pretty much the same caveat:

http://www.uspharmacist.com/NewLook/CE/glucocort/lesson.htm

Musculoskeletal Complications: Glucocorticoids are the most common cause of drug-induced osteoporosis.¹³ Glucocorticoids induce osteoporosis by suppressing intestinal calcium absorption, decreasing sex hormone production, and inhibiting bone formation. Approximately one out of five patients treated for one year with 7.5–10 mg of daily prednisone will develop skeletal fractures.¹⁴ ......All patients requiring long-term glucocorticoid therapy are candidates for osteoporosis prevention.¹³ ......The lowest possible steroid dose should be used, in order to minimize osteoporosis development.¹⁵

Being that our children are on replacement therapy, hopefully osteoporosis is not necessarily a foregone conclusion, but I do think that it pays to be pro-active about minimizing the possibility of bone loss. To me, among other things, this means trying to achieve control with as minimal a dose as is necessary;  taking as much care towards preventing oversuppression, as undersuppresssion; and adopting a cautious, moderate attitude towards stress-dosing.  Easier said than done, I know.