Subclinical Thyroid Disease and Risk for Hip Fracture

Overt hyperthyroidism is a known risk factor for osteoporosis and associated fracture, but risk associated with subclinical disease is unclear. Researchers used data from a national community-based prospective cohort study to assess hip-fracture risk in about 3500 adults (mean age at enrollment, 73) without overt thyroid disease; about 20% of them had subclinical thyroid dysfunction. Subclinical hyperthyroidism was defined as thyrotropin (TSH) level <0.45 mIU/L and subclinical hypothyroidism as TSH level between 4.5 and 20.0 mIU/L — both with normal free thyroxine (T₄) levels. Subclinical hypothyroidism was about three times as common as hyperthyroidism (14.9% vs. 4.7%).

During a median follow-up of 13 years, 331 hip fractures occurred. In a…