PERIPHERAL BONE-DENSITY IN WOMEN WITH UNTREATED MULTINODULAR GOITER

OBJECTIVES We wished to determine whether women with multinodular goitre and spontaneous subclinical hyperthyroidism have decreased bone density. DESIGN AND SUBJECTS Bone density was measured at the distal and proximal forearm. Data were expressed as Z-scores relative to the mean values out of 125 control subjects matched for age and menopause. The Z-scores of 23 women with subclinical hyperthyroid goitre (TSH < 0.1 mU/I and normal values for FT4 and total T3) and of 54 women with euthyroid goitre were compared. MEASUREMENTS Bone density was measured by single photon absorptiometry. TSH was measured by IRMA, FT4 by RIA. RESULTS Relative to the euthyroid goitre subjects the mean +/- SEM Z-scores of both the distal and proximal forearm density were lower (-0.69 +/- 0.17 vs 0.1 +/- 0.18, P < 0.05 and -0.5 +/- 0.18 vs 0.07 +/- 0.18, P < 0.05, respectively). Median (range) FT4 in the subclinical hyperthyroid goitre subjects was significantly higher than euthyroid goitre subjects (15.6 (11-23.2) pmol/l vs 11.9 (8.3-18.3) pmol/l, P < 0.001) although still within the normal range. FT4 correlated inversely with Z-scores of both distal and proximal forearm bone density in the subjects with subclinical hyperthyroidism (r= -0.42, P < 0.05 and r = -0.43, P < 0.05, respectively), but not in the euthyroid goitre subjects. CONCLUSION These findings indicate that women with untreated multinodular goitre and subclinical hyperthyroidism have reduced bone density in the forearm.