Fracture risk in patients with muscular dystrophy and spinal muscular atrophy.

We aimed at studying fracture risk in patients with Duchenne's muscular dystrophy (DMD), Becker's muscular dystrophy (BEMD), and spinal muscular atrophy type II and III (SMA II and III). A self-administered questionnaire was mailed to 293 patients with DMD, BEMD, SMA II or SMA III of which 229 returned the questionnaire. Each respondent was compared with an age- and gender-matched control subject. The mean age was 23.9 +/- 15.9 years for the patients and 23.3 +/- 16.5 years for the controls. There were significantly more fractures among patients than controls after the diagnosis was made (RR = 1.9), but not before. The patients had more fractures of the femurs, lower legs, and upper arms than the controls. Low energy fractures were more frequent in patients than controls (9% vs 0%). Many fractures in the femurs (40%), lower legs (35%), and feet and toes (44%) led to a permanent loss of function. Loss of ambulation was the major risk factor for fractures. In conclusion, fracture risk is increased in neuromuscular disease.