Objective. To determine the effect of 6 years of routine management on body composition, physical functioning, and quality of life, and their interrelationships, in men with idiopathic vertebral fracture. Methods. Twenty men with idiopathic vertebral fracture (patients: mean ؎ SD age 58 ؎ 6 years) were age and height matched to 28 healthy controls with no known disease. The primary outcome was skeletal muscle mass (appendicular lean mass by dual x-ray absorptiometry) assessed at 2 visits (0 and 6 years). Physical functioning and quality of life domains were assessed by the Senior Fitness Test and Short Form 36 (SF-36) questionnaire at visit 2 only. Data were analyzed by repeated-measures analysis of variance, independent t-tests, and correlation. Results. At visit 1, appendicular lean mass was 9% lower in patients than controls. Although patients better maintained appendicular lean mass between visits (interaction P ؍ 0.016), at visit 2 appendicular lean mass remained 5% lower in patients than controls. Furthermore, patients' appendicular lean mass change was correlated with femoral neck bone density change (r ؍ 0.507, P ؍ 0.023). Physical function tests were 13-27% lower in patients compared with controls (P ؍ 0.056 to 0.003), as were SF-36 quality of life physical domains (13-26% lower; P ؍ 0.028 to <0.001). Conclusion. Despite an association between changes in muscle mass and bone density, routine management of men with idiopathic vertebral fracture does not address muscle loss. Combined with the observation of reduced physical functioning and quality of life, this study identifies novel targets for intervention in men with idiopathic vertebral fracture.