Endogenous subclinical hyperthyroidism may not lead to bone loss in premenopausal women

Osteoporosis is defined as the decrease in bone mineral density. It is a serious health problem showing the predisposed person with increased bone fracture risk. Hyperthyroidism is one of the major causes of secondary osteoporosis. The aim of this study was to assess bone mineral density in premenopausal women with endogenous subclinical hyperthyroidism. A total of 168 subjects were included in this case-control study, of whom 86 and 82 participants were premenopausal women with subclinical hyperthyroidism and healthy premenopausal subjects, respectively. The patients with subclinical hyperthyroidism who were not receiving L-thyroxine treatment were included. The women in postmenopausal state or having chronic disease were excluded. The bone mineral densities of all subjects with dual energy X-ray absorptiometry were examined. The Z scores (femur and L1-4) of the study group were -0.15 ± 1.15 and -0.23 ± 1.03, respectively. The Z scores of the control group were -0.39 ± 1.08 and -0.55 ± 0.98, respectively. The differences between the groups were not statistically significant (p=0.14, 0.34, respectively). Our data suggest that contrary to exogenous subclinical hyperthyroidism, endogenous subclinical hyperthyroidism may not decrease bone mineral density in premenopausal women and it may not a risk factor for osteopenia or osteoporosis. Hippokratia 2014; 18 (3): 240-244.