Subclinical hyperthyroidism appears to be linked to increased fracture risk, according to data published in the Annals of Internal Medicine.
Currently, data conflict on the potential connection between subclinical thyroid dysfunction and fractures. To better understand this association, researchers searched Embase and Medline databases and identified and assessed prospective cohorts that measured thyroid function and fracture outcomes in study participants.
Seven population-based cohorts of heterogenous quality involving 50,245 participants were included in the analysis. Within these cohorts, there were 1,966 hip fractures and 3,281 non-spine fractures.
Results from a random-effects model including five higher-quality studies indicated that pooled HRs for participants with subclinical hyperthyroidism vs. euthyroidism were 1.38 for hip fractures and 1.20 for non-spine fractures. Pooled estimates for the seven cohorts were 1.26 for hip fractures and 1.16 for non-spine fractures, respectively.
After inclusion of participants receiving thyroxine, HRs for those with subclinical hyperthyroidism were 2.16 for hip fractures and 1.43 for non-spine fractures. HRs for participants with subclinical hypothyroidism from higher-quality studies were 1.12 for hip fractures and 1.04 for non-spine fractures, respectively.
The researchers noted that the study results are limited by the fact that selective reporting could not be excluded and potential confounder adjustment varied between studies. Therefore, they concluded that, although their data demonstrate an association between subclinical thyroid dysfunction and increased risk for fractures, larger and higher-quality studies are needed before drawing firm conclusions.
Subclinical hyperthyroidism might be associated with an increased risk for hip and nonspine fractures, but additional large, high-quality studies are needed.