Thyroid Disease Is Associated with Higher Age-Related Macular Degeneration Risk: Results from a Meta-Analysis of Epidemiologic Studies.

BACKGROUND

Although epidemiologic studies have suggested that thyroid disease may be a risk factor for age-related macular degeneration (AMD), this finding is still controversial.

OBJECTIVES

The aim of this meta-analysis was to investigate whether an association exists between thyroid disease and medication and AMD in epidemiologic studies.

METHODS

We searched PubMed, EMBASE, and Google Scholar from their inception to March 2020 for cross-sectional, case-control, and cohort studies that assessed thyroid function and AMD risk. Data from selected studies were extracted, and a meta-analysis was performed using fixed-effects or random-effects models. The statistical heterogeneity (I2) among studies and the possibility of publication bias were evaluated. If I2 >50%, a significant heterogeneity existed among studies, and a random-effects model was used to calculate the pooled RR. Otherwise, a fixed-effects model was performed.

RESULTS

A total of 13 epidemiologic studies that consisted of 7 thyroid disease and 7 thyroid medication studies were included. Statistically significant heterogeneity was observed in the study results (I2thyroid disease = 80.1%; I2thyroid medication = 69.0%). A significant positive association was found between thyroid disease and AMD, with an overall relative risk (RR) of 1.25 (95% CI: 1.02, 1.54). However, there was no statistical association between thyroid medication and AMD risk (pooled RR 1.26 [95% CI: 0.92-1.72]). Egger's test indicated that there was no significant publication bias for thyroid disease (p = 0.889) or thyroid medication (p = 0.226).

CONCLUSIONS

Our findings indicate that thyroid disease is associated with higher AMD risk. Thyroid disease prevention strategies may have a significant effect on the prevention of AMD and warrant further evaluation.