[Study of bone involvement in hypothyroidism determining the blood levels of osteocalcin]

Several bone abnormalities, characterized by a decreased bone turnover, may develop in patients with hypothyroidism. We have used the measurement of serum Osteocalcin (BGP), a protein synthesized by osteoblasts and proposed as a marker of bone formation, in order to elucidate the bone status in 62 hypothyroid patients, mean age 52 +/- 15 (SD) years. As a group, BGP results in hypothyroidism were not different from normal (3.6 +/- 3.2 vs 3.7 +/- 1.3 ng/ml). However, we were able to differentiate 3 groups: 1) patients with significantly lower BGP values (p less than 0.01) (primary hypothyroidism and total thyroidectomy with body scan); 2) patients with antithyroid drugs had significantly higher BGP levels (p less than 0.05); 3) in the other groups (post-1311, post-surgery, and insufficiently treated hypothyroidism) BGP values were within normal limits. In the total group BGP was significantly correlated with T3T, TSH, alkaline phosphatase and age. Lower serum BGP values in some etiologic groups of hypothyroidism may reflect a greater pathologic effect on the bone in these patients, with a decrease in bone formation.