Effects of long-term administration of methotrexate on bone mineral density in rheumatoid arthritis

Because previous studies of high-dose methotrexate usage have demonstrated an effect on bone formation and resorption, this study was done to determine whether long-term, low-dose use of methotrexate for the treatment of rheumatoid arthritis causes bone loss. Bone mineral density (BMD) of the lumbar spine and hip was measured in 10 Caucasian postmenopausal women who had never received methotrexate and 10 Caucasian postmenopausal women who had received the drug for 3 or more years. There were no significant differences in BMD at the lumbar spine (L2-L4) between patients who had used long-term methotrexate compared with patients never treated with methotrexate (1.08 ± 0.08 g/cm² versus 0.98 ± 0.14 g/cm², respectively; P = 0.08). Similarly, there were no significant differences in BMD at the femoral neck between methotrexate users and nonusers (0.81 ± 0.08 g/cm² versus 0.76 ± 0.15 g/cm², respectively; P = 0.42). These results suggest that long-term low-dose methotrexate treatment for rheumatoid arthritis is not associated with accelerated bone loss.