Risk of Osteoporosis and Fractures in Patients with Thyroid Cancer: A Case-Control Study in US Veterans

Background Data on osteoporosis and fractures in patients with thyroid cancer, especially men, are conflicting. Our objective was to determine osteoporosis and fracture risk in U.S. veterans with thyroid cancer. Materials and Methods This is a case-control study using the Veterans Health Administration Corporate Data Warehouse (2004-2013). Patients with thyroid cancer (n = 10,370) and controls (n = 10,370) were matched by age, sex, weight, and steroid use. Generalized linear mixed-effects regression model was used to compare the two groups in terms of osteoporosis and fracture risk. Next, subgroup analysis of the patients with thyroid cancer using longitudinal thyroid-stimulating hormone (TSH) was performed to determine its effect on risk of osteoporosis and fractures. Other covariates included patient age, sex, median household income, comorbidities, and steroid and androgen use. Results Compared with controls, osteoporosis, but not fractures, was more frequent in patients with thyroid cancer (7.3% vs. 5.3%; odds ratio [OR], 1.33; 95% confidence interval [CI], 1.18-1.49) when controlling for median household income, Charlson/Deyo comorbidity score, and androgen use. Subgroup analysis of patients with thyroid cancer demonstrated that lower TSH (OR, 0.93; 95% CI, 0.90-0.97), female sex (OR, 4.24; 95% CI, 3.53-5.10), older age (e.g., >= 85 years: OR, 17.18; 95% CI, 11.12-26.54 compared with <50 years), and androgen use (OR, 1.63; 95% CI, 1.18-2.23) were associated with osteoporosis. Serum TSH was not associated with fractures (OR, 1.01; 95% CI, 0.96-1.07). Conclusion Osteoporosis, but not fractures, was more common in U.S. veterans with thyroid cancer than controls. Multiple factors may be contributory, with low TSH playing a small role. Implications for Practice Data on osteoporosis and fragility fractures in patients with thyroid cancer, especially in men, are limited and conflicting. Because of excellent survival rates, the number of thyroid cancer survivors is growing and more individuals may experience long-term effects from the cancer itself and its treatments, such as osteoporosis and fractures. The present study offers unique insight on the risk for osteoporosis and fractures in a largely male thyroid cancer cohort. Physicians who participate in the long-term care of patients with thyroid cancer should take into consideration a variety of factors in addition to TSH level when considering risk for osteoporosis.