Some athletes, such as Tiger Woods and Barcelona soccer star Cesc Fabregas, manage to achieve moments of greatness despite severe injury. Tiger had a double stress fracture in his left tibia when he played and won the 2008 U.S. Open, and Fabregas had a fractured leg when he scored a penalty kick against Birmingham in 2010.

But for most people, a fractured bone is nothing to shrug off. In the U.S., there are about 2 million fractures annually. Vertebral or spinal fractures occur in 30% to 50% of people age 50 and older. Hip fractures may be less common, but more than 20% of people who fracture a hip never recover — and die within six months.

A study published in JAMA Network Open reveals a previously unrecognized risk factor that may account for some fractures: subclinical hyperthyroidism. This means your body is producing a bit too much thyrotropin (also called thyroid-stimulating hormone or TSH), a hormone that stimulates the production of two main thyroid hormones.

Having too much thyroid hormone can speed reabsorption of bone without increasing rebuilding of it.

Compared to people with normal thyroid function, those with subclinical hyperthyroidism have a 34% greater risk of a bone fracture over a couple of decades.

High blood pressure, diabetes, current smoking, and being Black were identified as the most common risk factors for subclinical hyperthyroidism.

The researchers recommend that everyone age 65 or older have their TSH levels checked periodically so that, if necessary, they can take medication to protect their bones.