The Degree of Bone Mineralization in Hyperthyroidism Estimated From the Phosphorus to Hydroxyproline Ratio in Bone

Abstract

The proportion between mineral and collagen in bone tissue, "the degree of mineralization", can be evaluated from the phosphorus to hydroxyproline ratio (P/Hypro ratio), determined in bone biopsies. The ratio was measured in 27 unselected hyperthyroid patients. No significant correlation was found between the P/Hypro ratio and the age of the patient, the duration of the disease or the value of serum thyroxine. The mean value of the P/Hypro ratio for the group studied was not significantly different from the normal mean. The results of the study indicate a normal degree of mineralization in the bone of patients with hyperthyroidism. Though rather asymptomatic in most patients, bone changes have been de¬ scribed for many years in the hyperthyroid state (von Recklinghausen 1891). The incidence of bone changes has been dependent on the method of investig¬ ation. Striation of the cortex of the metacarpal bone cortex was found on x-ray examination in 75fl/o of patients with hyperthyroidism (Meema 8c Meema 1972) whereas a decreased cortical width was found in only a few patients (Ikkos et al. 1971; Koutras et al. 1973; Meema 8c Meema 1972). By osteodensitometric methods a low mineral content was found in about 25 % of patients (Fraser et al. 1971; Meema 8c Meema 1972). Bone histology has shown divergent results in hyperthyroidism. Sometimes increased osteoid surfaces as in osteomalacia