Association between thyroid dysfunction and diabetic retinopathy: a two-sample bidirectional Mendelian randomization...

Area of Science:

• Endocrinology
• Ophthalmology
• Genetics

Background:

• Diabetic retinopathy (DR) is a leading cause of vision loss.
• Thyroid dysfunction is a common endocrine disorder.
• The causal relationship between thyroid dysfunction and DR remains unclear.

Purpose of the Study:

• To investigate the bidirectional causal relationship between thyroid dysfunction (hyperthyroidism and hypothyroidism) and diabetic retinopathy (DR).
• Utilize a two-sample Mendelian randomization (MR) approach with large-scale Genome-wide Association Study (GWAS) data.

Main Methods:

• Employed a two-sample bidirectional Mendelian randomization (MR) study design.
• Utilized GWAS data for thyroid dysfunction (hyperthyroidism, hypothyroidism) and DR in European populations.
• Applied inverse variance weighting (IVW) as the primary analysis, with MR-Egger, weighted median, and other methods for robustness checks.

Main Results:

• Forward MR analysis showed hyperthyroidism and hypothyroidism significantly increase the risk of DR (IVW ORs > 1, P < 0.001).
• Reverse MR analysis indicated DR significantly increases the risk of developing hyperthyroidism and hypothyroidism (IVW ORs > 1, P < 0.001).
• Sensitivity analyses confirmed the reliability of the causal findings and ruled out significant pleiotropy.

Conclusions:

• This study provides robust genetic evidence for a bidirectional causal relationship between thyroid dysfunction and diabetic retinopathy.
• Findings suggest that managing thyroid health may be important for preventing or managing DR, and vice versa.