Increased frequency of osteoporosis and BMD below the expected range for age among South Korean women with rheumatoid arthritis
To compare the frequency of osteoporosis and bone mineral density (BMD) below the expected range for age between female patients with rheumatoid arthritis (RA) and healthy subjects and to determine risk factors for bone loss in female patients with RA. Two hundred and ninety-nine patients with RA and 246 age-matched healthy subjects were included in this study. BMD in the lumbar spine, femoral neck and total hip were measured with dual-energy X-ray absorptiometry. A T-score of -2.5 or lower in postmenopausal women was defined as osteoporosis, and a Z-score -2.0 or lower in females prior to menopause was defined as below the expected range for age. The frequency of osteoporosis in the RA patients (22.1%) was significantly higher than in healthy subjects (11.4%) at either the spine or hip (P = 0.014). The occurrence of BMD below the expected range for age in RA patients (7.8%) was also significantly higher than in healthy subjects (1.0%, P = 0.015). In 299 female patients with RA, higher age, lower body mass index and postmenopausal status were significantly associated with the lumbar spine and hip BMD reduction. Of disease-related variables, glucocorticoid use was independently associated with reduction of hip BMD. The prevalence of osteoporosis in the RA patients was 1.9 times higher than in healthy subjects. Glucocorticoid use was a risk factor for generalized bone loss in female RA patients.