Trabecular Bone Score and Vertebral Fracture Assessment in Portuguese Premenopausal Women with Hyperthyroidism

Abstract

Hyperthyroidism is a risk factor for reduced bone mineral density (BMD) and osteoporotic fractures. Vertebral fracture assessment (VFA) detects vertebral fractures and trabecular bone score (TBS) is an index of bone micro-architecture. We aimed to evaluate the effects of hyperthyroidism on BMD, soft body tissue composition, prevalence of silent vertebral fractures and TBS. Eighty Portuguese pre-menopausal women were divided and matched in overt hyperthyroidism (n=40) and control (n=40) groups. BMD (g/cm2) at lumbar spine, hip, radius 33% and whole body and the total body masses (Kg) were studied by DXA. VFA was used to detect fractures and those were classified by Genant´s semi-quantitative method and confirmed by X-ray. TBS was obtained from lumbar spine DXA images. No patient had previously been treated for hyperthyroidism, osteoporosis or low bone mass. Adequate statistical tests were used. In the hyperthyroidism group, the mean BMD (total hip, femoral neck and whole body), the total lean mass and TBS were significantly lower; according to ISCD classification, there was a trend for a higher prevalence of low BMD; vertebral fractures were significantly higher. These results suggest that in a group of hyperthyroid pre-menopausal women there are significantly lower BMD, lean mass and TBS. The prevalence of silent vertebral fractures is also significantly higher. All patients and controls gave their informed consent, according to the approved protocol by the ethic committee of the institution and based on Helsinki declaration. Declaration of Interest: We declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported. Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.