Bone mineral density in pre-and post-menopausal women with affective disorder treated with long-term L-thyroxine augmentation

Background: Augmentation with TSH-suppressive L-thyroxine (T4) has been sho wn to improve the course of illness in otherwise refractory affective disor ders. This collaborative study investigates whether T4 augmentation for a m inimum of 12 months decreases bone mineral density (BMD) in 26 pre- and pos t-menopausal women with affective disorder. Methods: We measured BMD at the femoral neck, Ward's triangle, trochanter and lumbar vertebrae (L1-L4) in 13 premenopausal and 13 postmenopausal women with affective disorder using dual energy X-ray absorptiometry. BMD was expressed as g/cm(2) and as a Z-s core, calculated using bone density data from the international reference p opulation standard. Results: The Z-scores for the pre- and post-menopausal women were within the reference range of the age and sex matched population standard. BMD for the composite group also did not differ either from the population standard. BMD in the lumbar spine and hip did not differ signifi cantly between the pre- and post-menopausal groups. However, there were a r elatively high number of postmenopausal patients with BMDs one S.D. lower t han the population standard. Limitations: This is a cross-sectional study w ith a relatively small sample size. Conclusions: The study demonstrates tha t T4 augmentation treatment does not reduce BMD to a clinically significant degree in many women with affective disorder, However, the resilience of b one structure to T4 treatment may vary with site and menopausal status, Thi s study underscores the need for regular assessment of BMD during adjunctiv e thyroid treatments for affective disorder. especially in postmenopausal w omen. (C) 2001 Elsevier Science B.V. All rights reserved.