Fibromyalgia (FM) may t cause a decrease in bone mineral density (BMD) because of decreased mobility. The condition is relatively frequent in rheumatoid arthritis (RA) and RA patients with FM have more disability than those without FM. We evaluated the effect of FM on BMD and investigated the effect of FM on BMD in RA patients.
We included age-matched 56 FM, 52 RA patients, and 37 healthy females as controls. Twenty three of all RA subjects met 1990 ACR FM criteria. Patients using the antiresorptive drugs, those on hormone replacement therapy, patients with thyroid or parathyroid dysfunction were excluded. Self-reported pain and fatigue severity, functional items of FM impact questionnaire were questioned in FM and RA patients. In all subjects, BMD of the lumbar spine and femur neck were determined by dual X-ray absorptiometry, and T-scores were recorded.
Self-reported pain and fatigue scores in FM subjects were significantly higher than in RA patients (P<0.001). The mean lumbar spine and femur neck BMD and their T-scores in RA patients were significantly lower than in FM and control groups (P values<0.01). There was no difference in BMD between FM subjects and the control group. BMD in RA patients with and without FM were similar (P>0.05). There was a significant negative correlation between self-reported pain score and lumbar spine BMD in FM subjects (r=-0.41, P=0.006).
In spite of functional disability, FM does not cause a decrease in BMD. The presence of FM in RA patients does not result in a change in BMD.