The influence of thyroid disorders on bone density and biochemical markers of bone metabolism

Background: Thyroid dysfunction, predominantly hyperthyroidism, has been previously linked to impaired bone mass density (BMD) and increased risk of fractures. On the other hand, data in the field of hypothyroidism (HT) are missing. The purpose of the present study was to investigate the impact of thyroid disorders on bone density serum and urine calcium (Ca) and phosphate (P) as well as serum osteocalcin and alkaline phosphatase and urine hydroxyproline in a series of post-menopausal women. Materials and methods: The study was conducted in the Reproductive Endocrinology Outpatient Clinic of our hospital. A consecutive series of post-menopausal women was included, after excluding patients under hormone treatment (including levothyroxine supplementation) and those who received raloxifene, tamoxifen or tibolone during the study period as well as those who received treatment during the previous 12 months were excluded from the present study. Results: Overall, 188 women were included in the present study. Among them, 143 women had normal thyroid function, 32 women had hyperthyroidism and 13 women had HT. Correlation of thyroid function indices with osteoporosis indices revealed statistically significant correlations between thyroxine (T4) and free triiodothyronine (T3) with T-, Z-scores and BMD. Logistic regression analysis concerning the impact of HT and hyperthyroidism on T-score, Z-score and bone mass density revealed that both pathological entities negatively affect bone health (p < 0.05). Conclusion: The findings of our study suggest that not only hyperthyroidism, but also HT negatively affects BMD. Future studies should investigate this association and corroborate our findings.