Liu S, Sun Q, Gu Q, Bao Y, Wang W, Qin X, Yuan X. Hypothyroidism is a causal determinant of age-related cataract risk in European population: a Mendelian randomization study.
Front Endocrinol (Lausanne) 2024;
15:1254793. [PMID:
38375193 PMCID:
PMC10874999 DOI:
10.3389/fendo.2024.1254793]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 01/15/2024] [Indexed: 02/21/2024] Open
Abstract
Objective
To determine whether there is a causal relationship between thyroid dysfunction and the risk of age-related cataract (ARC) in the European population.
Design
A two-sample Mendelian randomization (MR) study.
Methods
Hypothyroidism, hyperthyroidism, free thyroxine (fT4), and thyrotropin (TSH) were selected as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were obtained from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for fT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. ARC was used as the outcome. The SNPs associated with ARC were selected from a GWAS of 216,362 individuals in the FinnGen database. The main method used was the inverse variance-weighted method, together with four complementary methods. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO, MR-Egger regression and leave-one-out test. MR pleiotropy was used to test for pleiotropy. MR Steiger test was used to test for the directionality.
Results
Two-sample MR analysis revealed a positive association between genetically predicted hypothyroidism and risk of ARC (OR = 2.501, 95% CI: 1.325-4.720; P = 0.004). Hyperthyroidism, circulating fT4 and TSH levels did not have a significant causal effect on ARC (P > 0.05). The results were robust and reliable, and no horizontal pleiotropy was found after sensitivity analyses. In the MR Steiger test, we found no reverse causal effects of hypothyroidism on the ARC (P <0.001).
Conclusions
Our study provides strong evidence that hypothyroidism is a causal determinant of ARC risk.
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