Subclinical hyperthyroidism may be an independent risk factor for fractures, a community-based cohort study found.
In the analysis of nearly 11,000 middle-age individuals, having subclinical hyperthyroidism was tied with a 34% higher risk for subsequent fracture versus those with euthyroidism during a median 21-year follow-up (adjusted HR 1.34, 95% CI 1.09-1.65), according to Stephen P. Juraschek, MD, PhD, of Beth Israel Deaconess Medical Center in Boston, and colleagues.
Compared with those with normal thyrotropin and free thyroxine levels, however, fracture risk was not associated with subclinical hypothyroidism (aHR 0.90, 95% CI 0.77-1.05), the group reported in JAMA Network Open.
The models were adjusted for several factors including age, sex, race, diabetes status, menopausal status, body mass index, and vitamin D levels.
During the two-decade follow-up, there were a total of 3,556 new fractures recorded (167.1 fractures per 10,000 person-years). The rate of incident fractures per 10,000 person-years was:
- 192.7 for those with subclinical hyperthyroidism
- 180.8 for those with subclinical hypothyroidism
- 165.8 for those with euthyroidism
The most common fracture locations were hip (14.1%) and spine (13.8%). Fracture-related hospitalizations were also far more common among those with thyrotropin levels below 0.56 mIU/L.
“Those with mildly suppressed thyrotropin levels (0.1 mIU/L to
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