Hawker GA, Ridout R, Harris VA, Chase CC, Fielding LJ, Biggar WD. Alendronate in the treatment of low bone mass in steroid-treated boys with Duchenne’s muscular dystrophy. To examine alendronate’s side-effect profile and effect on bone mineral density (BMD) in deflazacort-treated boys with Duchenne’s muscular dystrophy (DMD) and low BMD. Before-after trial. Neuromuscular clinic at a children’s hospital in Canada between 1999 and 2000. All consenting boys with DMD who had z scores less than −1.00 (spine and/or total body) and in whom BMD testing was feasible. Boys received .08mg·kg −1 ·d −1 of alendronate orally, with 750mg of daily calcium and 1000IU of vitamin D. BMD, height, weight, physical activity, Tanner stage, and adverse effects were followed for 2 years. BMD z scores at the lumbar spine (L1-4) and total body. Of the 42 eligible boys assessed, 23 had low BMD; for 16 of the 23, future BMD testing was feasible. Mean age was 10.8 years (range, 6.9–15.6y). Mean baseline z scores at the total body and spine were −0.80 and −1.94, respectively. At 2 years, mean z scores were unchanged. Furthermore, alendronate response varied by baseline age. In multivariable analysis, improvement in total body and spine z scores was associated with younger age at baseline (P=.01 for both). In deflazacort-treated boys, alendronate had a positive effect on BMD z scores; the effect was greatest when given early in the course of disease.