Evaluation of thyroid function status among postmenopausal women with and without osteoporosis

Abstract Objective To investigate the relationship between thyroid function status and bone mineral density (BMD) among women with postmenopausal osteoporosis. Methods A retrospective study was performed among 1217 women aged 45–80 years who attended the Department of Obstetrics and Gynecology at Dokuz Eylul University, Izmir, Turkey, between August 1, 2009, and June 1, 2013. Eligible participants were grouped according to the presence or absence of osteoporosis as defined by BMD measurements at the lumbar vertebrae (L1–L4), femoral neck, or trochanter of the femur. Serum levels of free tri-iodothyronine, free tetraiodothyronine, and thyroid-stimulating hormone (TSH) were assessed. Results The 303 women with osteoporosis had a lower mean TSH level (1.8 mIU/L) than did the 914 women without osteoporosis (1.9 mIU/L; P = 0.01). A positive correlation between TSH level and measures of BMD was observed ( P = 0.01). The TSH level was associated with a protective effect in a regression model for development of osteoporosis; the odds ratio was 0.68 (95% confidence interval 0.53–0.86). Conclusion Osteoporosis appeared to be independently associated with serum TSH level. Maintaining TSH levels within the upper limit of the reference range during treatment of hypothyroidism could be important to prevent osteoporosis among postmenopausal women.