Bone mineral density in patients with hyperthyroidism measured by dual energy X-ray absorptiometry

OBJECTIVE We assessed the changes of bone mass in patients with hyperthyroidism by measuring bone mineral density using a new method, dual energy X-ray absorptiometry. DESIGN The values of bone mineral density in patients with hyperthyroidism were compared with data obtained from the controls, and we assessed the correlation analysis between bone mineral density and several metabolic parameters. PATIENTS We studied 52 Japanese patients with hyperthyroidism (20 males, 32 females). Healthy normal subjects served to establish the mean bone mineral density In the healthy Japanese population (Shiraki et al. 1991). MEASUREMENT Bone mineral density was assessed by the measurement of lumbar vertebrae and femur by dual energy X-ray absorptiometry. The bone mineral density of vertebrae for each patient was calculated as the percentage of the mean value (% bone mineral density) obtained from an age and sex-matched control group. Blood was drawn to measure the levels of serum calcium, phosphorus, creatinine, alkaline phosphatase, free T3, free T4, TSH, TSH receptor antibody, parathyroid hormone, and serum osteocalcin. RESULTS The percentage bone mineral density of vertebrae in patients was 92.6 as compared with that of normal controls, and was inversely correlated with serum TSH receptor antibody, osteocalcin, and alkaline phosphatase. CONCLUSIONS These findings suggest that bone mineral density is decreased in patients with hyperthyroidism and that TSH receptor antibody, osteocalcin, and alkaline phosphatase are sensitive markers of bone metabolism alterations in hyperthyroidism.