OBJECTIVE To investigate bone mineral density (BMD) in men with symptomatic osteoporosis and compare BMD in patients with idiopathic, secondary and corticosteroid associated osteoporosis.

RESULTS Age at peak BMD in controls was 20–29 years at spine (LS-BMD) and femoral neck (FN-BMD). LS-BMD did not change with age but FN-BMD decreased in controls and groups 1 and 2. Mean (SD) age was similar in groups 1 (62.8 (11.5) years, 2 (60.2 (11.0)) years and 3 (62.7 (10.4) years with 45%, 51% and 40% of patients respectively presenting before 60 years. Back pain, present for up to 12 months, was the commonest cause of referral. Vertebral fractures at presentation averaged mean (SD) 2.51 (1.9) in group 1, 2.76 (2.2) in group 2 and 2.48 (1.8) in group 3. LS-BMD Z scores and T scores were more negative in group 1 patients with ⩽3 vertebral fractures compared with FN-BMD suggesting a greater trabecular bone deficit. LS-BMD Z score in group 1 is −1.71, lower than in population studies. LS T score associated with fracture was about −2.4 in all groups. T8, T12 and L1 were the most frequent levels for fracture.

CONCLUSIONS Men with symptomatic osteoporosis present in middle age, have low BMD with similar T scores irrespective of aetiology and sustain ⩾ 1 fracture.