Effect of block-replacement regimen on bone mineral density and biochemical markers in patients with thyrotoxic bone disease

Intorduction: Abnormal bone metabolism in patients with thyrotoxicosis is well documented, but time-course of recoveryremains poorly understood. Objective: To evaluate changes in bone density and bone metabolic parameters in thyrotoxicosis before and after therapy. Methods: Forty patients with thyrotoxicosis (11 males; mean age 35.5 ± 9.9 years) rendered euthyroid with methimazoleand maintained on block-replacement therapy were followed up for six months at a tertiary care setting. Of these, 21 hadcompleted follow-up evaluation. Bone mineral density (BMD) at lumbar spine (LS), hip and biochemical markers wereestimated before and after therapy. Results: At LS, 21% women and 35% men had a Z score less than ?2. At the neck of femur (NOF),17% women and 18%men had Z score less than -2. LS was more severely affected (p < 0.001). BMD was similar among patients who were 25- hydroxy vitamin D [25(OH)D] deficient,[25(OH)D < 20 ng/mL ( 30 ng/mL (>50 nmol/L)]. Serum T4 correlated negatively with Z-scores at LS, NOF, trochanter and Ward’s area. There was improvement in BMD (p