• methotrexate
• bone mineral density
• bone turnover

Wijnands and Burgers recently reported on a patient with psoriasis who developed stress fracture of the leg thought to be related to methotrexate treatment.¹ The role of methotrexate in the aetiology of fractures remains uncertain, because nearly all subjects reported had other risk factors for fracture, such as the underlying disease being treated. We recently examined a group of patients with psoriasis (without features of arthritis, to avoid the bias which may occur due to the arthritis and compensatory action of methotrexate on inflammatory disease activity)² to assess the effect of methotrexate on bone density and turnover.

After approval from the local ethics committee, patients with psoriasis, but without psoriatic arthritis or diseases or drug treatment known to adversely effect the skeleton, were recruited. We obtained information by interview and measured bone mineral density (BMD) by dual x ray absorptiometry (DXA) using a Lunar DPX device (Lunar Corp, Madison, WI). Daily calibration measurements using an external phantom were performed and monitored for machine drift. No significant drift was noted during the study period. Precision was calculated by the method of Gluer et al,² and at our centre is 1.3% for the lumbar …