['To assess the benefit of cyclical etidronate plus ergocalciferol for the prevention of glucocorticoid-induced bone loss in a 2-year, prospective, open study based in an osteoporosis clinic.', 'Group 1 consisted of 15 postmenopausal women (mean age 62.6 +/- 3.3 years) who commenced glucocorticoid therapy and were treated with cyclical etidronate (400 mg/d for the first month; thereafter, 400 mg/d for 2 weeks of every 3-month period), elemental calcium (1 g/d), and ergocalciferol (0.5 mg/wk). Group 2 consisted of 11 postmenopausal women (mean age 60.2 +/- 4.7 years) with glucocorticoid-induced osteoporosis, who were attending the clinic at the same time and were treated with calcium supplements only (1 g/d).', 'Lumbar spine and femoral neck bone mineral densities (BMD) were measured at baseline and after 12 and 24 months of glucocorticoid therapy using a dual energy x-ray absorptiometer.', 'The two groups did not differ with respect to age, years since the menopause, mean daily glucocorticoid dose, and baseline BMD values. During the first year of therapy, mean lumbar spine BMD increased from an initial value of 0.88 g/cm2 to 0.94 g/cm2, an increase of 7% per year (95% confidence interval [CI] 3.7% to 10.2%; P < 0.001 compared with controls). Significant increases in BMD of 2.5% per year were also observed in the femoral neck (95% CI -1% to 6%; P < 0.01 compared with controls). After the second year of cyclical etidronate therapy, femoral neck BMD continued to increase (P < 0.05 compared with value at 12 months), while lumbar spine BMD remained stable.'] Does cyclical etidronate plus ergocalciferol prevent glucocorticoid-induced bone loss in postmenopausal women?