Thyroid disease may be associated with a higher risk for age-related macular degeneration (AMD), according to results of a meta-analysis published in Ophthalmic Research. These results underline the importance of thyroid disease prevention strategies to preserve ocular health. 

Previous research into the relationship between thyroid hormone and AMD has demonstrated some association, but evidence has been inconsistent. In the current meta-analysis, researchers sought to examine the current literature and accurately assess the relationship between thyroid disease, thyroid medication, and AMD. 

Thirteen studies were included in the meta-analysis. Seven studies focused on thyroid disease and 7 focused on thyroid medication; 1 article included information on both. 


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The 7 studies focused on the relationship between thyroid disease and AMD included a total of 61,993 patients. Overall, these studies found that thyroid disease was associated with a 25% increase in AMD risk (summary relative risk [RR], 1.25; 95% CI, 1.02-1.54). However, statistically significant heterogeneity was noted in the study results (I2=80.1%; P <.001).

The 7 studies focused on the relationship between thyroid medication use and AMD included a total of 118,420 patients. For the meta-analysis, investigators used a random-effects model, which found a pooled RR of 1.26 (95% CI, 0.92-1.72) for the association between thyroid medication use and AMD. These results were also heterogenous (I2=69%; P =.004).

Results of an Egger’s test did not indicate publication bias for either group of studies (P =.889 and P =.226 for thyroid disease and thyroid medication studies, respectively). 

Sensitivity analyses were used to recalculate the combined results through the exclusion of 1 study per iteration. Results of this analysis were similar to the original analysis, with no drastic changes in RR estimates. 

Study limitations include insufficient data on the long-term exposure of thyroxine and AMD, inconsistent adjustment for potential confounders between studies, and a lack of reporting on AMD type in studies, making it impossible to perform subgroup analyses using this variable. 

“Our results indicate that there was an increased incidence of AMD in patients with thyroid disease,” the study concludes. “Thyroid disease prevention strategies may have a significant effect on the prevention of AMD and warrant further evaluation.” 

Reference

Xu Z, Zhang M, Zhang Q, Xu T, Tao L. Thyroid disease is associated with higher age-related macular degeneration risk: Results from a meta-analysis of epidemiologic studies. Published online February 17, 2021. Ophthalmic Res. doi:10.1159/000515273