Thyrotropin levels within the lower normal range are associated with an increased risk of hip fractures in euthyroid women, but not men, over the age of 65 years

Abstract

Context: The contemporary literature on the relationship between serum TSH levels and osteoporotic fractures in euthyroid individuals is limited by conflicting results and analyses conducted on a small number of fractures. Objective: Our objective was to examine the association between the normal range of variation of TSHandthe incidence of hip fractures in maleandfemale euthyroid patientsaged65 years or older. Design and Setting: We performed a population-based historical prospective cohort study within the Clalit Health Services population. Participants: Clalit Health Services members aged ≥65 years with at least 1 TSH measurement during the year 2004. We excluded patients with preexisting hip fracture, thyroid disease, malignancy, or chronic kidney disease. Outcome Measures: The primary outcome was hip fracture, and the secondary outcome was any other osteoporotic fracture. Statistical Analysis: Adjusted odds ratios comparing episodes of each outcome across 3 TSH groups (low, 0.35-1.6 mIU/L; intermediate, 1.7-2.9 mIU/L; high, 3-4.2 mIU/L) were generated using logistic regression models. Results: The 14 325 included participants suffered from 514 hip fractures (mean follow-up, 102 = 3 months). Women, but not men, in the lowest TSH group had a higher incidence of hip fractures (odds ratio = 1.28, 95% confidence interval = 1.03-1.59, P = .029) when compared with the intermediate group, after multivariate adjustment for age, comorbidities, and use of drugs affecting bone metabolism. There wasnodifference in hip fracture incidence between intermediateand high-TSH groups. No association was found between TSH levels and other osteoporotic fractures. Conclusions: TSH levels within the lower normal range are associated with an increased risk of hip fractures in euthyroid women, but not men, aged 65 years and more. Copyright © 2014 by the Endocrine Society.