Subclinical hyperthyroidism significantly associated with increased fracture risk: JAMA

A recent study by Natalie Daya found that subclinical thyroid dysfunction was closely associated with fracture. The findings were further published in the November 2022 edition of Journal of American Medical Association.

A total of 10,946 participants from the Atherosclerosis Risk in Communities Study was included in the study. These participants were from community-dwelling individuals Maryland, North Carolina, Mississippi, and the suburbs of Minneapolis, Minnesota. They were not taking thyroid medications and also had no history of fractures. 

The normal range of free thyroxine levels from 0.85 to 1.4 ng/dL. The measured thyrotropin level lesser than 0.56 mIU/L was defined as subclinical hyperthyroidism, thyrotropin level higher than 5.1 mIU/L defined as subclinical hypothyroidism, and thyrotropin level of 0.56 to 5.1 mIU/L was considered euthyroidism.

The findings of the study were:

1. Of the total participants 93.0% had euthyroidism, 2.6% had subclinical hyperthyroidism, and 4.4% had subclinical hypothyroidism.

2. A total of 3556 incident fractures were faced during the median follow up of 21 years.

3. The adjusted hazard ratios of fracture were 1.34 for those with subclinical hyperthyroidism and 0.90 for those with subclinical hypothyroidism compared with individuals with euthyroidism.

4. In people with normal free thyroxine levels,

• Individuals with thyrotropin levels in the lower than the normal range were closely associated to a higher fracture-related hospitalization risk.

• Fracture risk was higher in individuals with thyrotropin concentrations less than 0.56 mIU/L.

In conclusion, this study clearly suggests that subclinical hyperthyroidism is closely associated with fracture risk. This calls for more aggressive screening and monitoring of the patients to prevent further events and bone mineral disease.

Source:

Daya, N. R., Fretz, A., Martin, S. S., Lutsey, P. L., Echouffo-Tcheugui, J. B., Selvin, E., & Juraschek, S. P. (2022). Association Between Subclinical Thyroid Dysfunction and Fracture Risk. In JAMA Network Open (Vol. 5, Issue 11, p. e2240823). American Medical Association (AMA).https://doi.org/10.1001/jamanetworkopen.2022.40823