Background & Aims : Many reports show a relation between exogenous thyroxine therapies on bone mineral density but the net effects remain unclear. The aim of this study was to determine the effect of replacement dose of levothyroxine on bone mineral density in premenopausal women with primary hypothyroidism .

  Materials & Methods: This study included 50 women with primary hypothyroidism. Patients with history of thyroid surgery and iodine ablation, patients with other diseases, or drugs that interfered with bone mineral density were excluded from this study. Bone mineral density was measured before and after 24 months of replacement dose of levothyroxine treatment. Statistical analysis was done by paired t-test. The data before and after levothyroxine therapy were compared with each other .

  Results : The mean age of patients was 34.4 ±5.3 years. The mean lumbar bone mineral percent before treatment was %78.8±15.2 and mean T score in lumbar area was -1.4±0.86. After two years of treatment, the mean lumbar bone mineral percent and lumbar T score changed to %78.4±13.6 and -1.7±0.57, respectively. The mean bone mineral percent in neck of femur was %88.47±13.04 and T score was -1.05±1.07 before treatment that changed to %92.0±8.07 and T score -0.9±0.88 after levothyroxine treatment. These changes were not significant .

  Conclusion : Replacement dose of Levothyroxine therapy for at least two years in pre-menopausal women with hypothyroidism does not cause any significant change in bone mineral density .

    Source: Urmia Med J 2011: 22(5): 490 ISSN: 1027-3727