Abstract. Objective: To estimate the prevalence of osteoporosis in patients being treated with thyroid hormone. Method: Cross-sectional retrospective study of primary care patients. Experimental Group: 112 patients diagnosed with subclinical hypothyroidism receiving thyroid hormone replacement therapy. Control Group: 70 subclinical hypothyroid patients not receiving thyroid replacement therapy. Once the sample was selected its members completed a clinical questionnaire and underwent a bone density scan with a validated measuring device. Results: Among the 182 patients studied, respectively, the experimental groups’ mean age at diagnosis was 42.5 and the control patients’ was 41.2 years; 32.7% were smokers as opposed to 33.2%; the coexistence of two or more cardiovascular risk factors were detected in 5.7% of experimental patients as opposed to ?% of control patients; mean TSH was 6.67 mU/L and mean free T4 was 1.04 ng/dL, compared to 5.95 mU/L and 0.98 ng/dL. The experimental and control groups significantly differed in percentage of reduced bone mineral density: respectively, 67% vs 35% lost bone mass, 86% vs 54% osteopenia, and 14% vas 5% osteoporosis. Fifty-six percentage of patients with bone loss were women. Control patients use no thyroid therapy for any time; in contrast, 72% of experimental patients used 100 or more mcg of T4 and 12% use 150 mcg/day or more. Duration of T4 treatment was 1-to-10 years for 61.1% of the patients and 10 years or more for 19.5%. Conclusions: The data used in this study indicate a high prevalence of bone loss in patients with subclinical hypothyroidism treated with exogenous thyroxine.

Keywords • Bone mass loss • Osteopenia • Osteoporosis • Subclinical hypothyroidism • Thyroxine replacement

Citation: Tárraga López,P.J., de Mora, F.N., Rodríguez Montes, J.A., Solera Albero, J., Naharro Mañez, A., Frias López, Mª C.:Osteoporosis in patients with subclinical hypothyroidism treated with thyroid hormone replacement. Thyroid Science, 6(6):CLS1-9, 2011.