Causal role of thyroid function in functional outcome after ischemic stroke: A Mendelian randomization study.

Area of Science:

• Endocrinology
• Neurology
• Genetics

Background:

• Observational studies suggest a link between thyroid function and functional outcomes after ischemic stroke (IS).
• The causal relationship between thyroid function and post-IS recovery remains unclear.
• Thyroid function markers include thyroid-stimulating hormone (TSH), free thyroxine (FT4), hyperthyroidism, and hypothyroidism.

Purpose of the Study:

• To investigate the causal effect of thyroid function on functional outcomes after IS.
• Utilized two-sample Mendelian randomization (MR) analysis to explore causality.
• Assessed the impact of TSH, FT4, hyperthyroidism, and hypothyroidism on the modified Rankin scale post-IS.

Main Methods:

• Employed the inverse variance weighted (IVW) method as the primary analysis.
• Utilized six additional MR methods (MR-Egger, weighted median, etc.) for robust assessment.
• Conducted sensitivity analyses including Cochrane's Q test, MR-Egger intercept, MR-PRESSO, and leave-one-out tests to ensure reliability.

Main Results:

• Elevated TSH levels were significantly associated with improved functional outcomes after IS (OR = 0.74, P = 0.028).
• Consistent results were observed across multiple MR methods.
• No significant causal effect was found for FT4, hyperthyroidism, or hypothyroidism on IS functional outcomes.
• Sensitivity analyses confirmed the reliability of the MR findings, with no significant heterogeneity or horizontal pleiotropy detected.

Conclusions:

• Mendelian randomization analysis supports a beneficial role of elevated TSH levels in functional recovery after IS.
• Regular monitoring and management of TSH levels could be a therapeutic strategy for IS patients.
• Findings highlight the potential importance of thyroid function regulation in stroke rehabilitation.