Thyroid Dysfunction Does Not Affect the Bone Mineral Density in Postmenopausal Women

Aim: To investigate the relationship between bone mineral density (BMD) and thyroid dysfunction in postmenopausal women. Material and Method: A total of 261 postmenopausal women, who were examined between 2006 and 2008, were included in this prospective cohort study. Levels of thyroid stimulating hormone (TSH), free T3 (triiodothyronine), free T4 (tiroxin), and thyroid antibodies (anti-thyroglobulin antibody -antiTG Ab; anti-thyroid peroxidase antibody - antiTPO Ab) were measured in all subjects. The subjects were classified into four groups: hyperthyroidism, hypothyroidism, autoimmune thyroiditis, and euthyroid(control). Bone mineral densities (BMDs) from the lumbar 1–4 (L 1–4) vertebrae and the femoral neck regions of interest were measured using the dual energy x-ray absorptiometry (DEXA) method and used to yield T-score values which were compared between groups. Results: The mean L1 – 4 T-score was 1.26 ± 1.25 in 56 cases (21.5%) with hypothyroidism ; -1.46 ± 1.36 in 42 (16.1%) cases with hyperthyroidism and -1.51 ± 1.22 in 37 cases (14.2%) with autoimmune thyroiditis . The mean L1 – 4 T-score of the control group that consisted of 126 (48.3%) cases was -1.28 ± 1.20. The mean femoral neck T-score was -0.31 ±1.15 in hypothyroid group; -0.80 ±1.41 in hyperthyroid group and -0.60 ±1.19 in cases with autoimmune thyroiditis . The mean femoral neck T-score of the control group was -0.55 ±1.08. When the T-scores of the entire L1 – 4 region and those of the femoral neck were compared, the values were not significantly different between the four patient groups (p = 0.680 and p = 0.258, respectively). Discussion: The present study indicated that thyroid dysfunction does not significantly affect BMD in postmenopausal women with hyperthyroidism, hypothyroidism, or autoimmune thyroiditis. This result suggests that thyroid dysfunctions do not have a significant role in the development of osteoporosis during the postmenopausal period, perhaps because there may be other mechanisms at work that blunt or mask the effects of thyroid hormones