Causal effect of thyroid function on cortical brain structure: A two-sample Mendelian randomization study.

Area of Science:

• Neuroscience
• Genetics
• Endocrinology

Background:

• The relationship between thyroid dysfunction and brain structure is not well understood.
• Mendelian randomization (MR) is a powerful tool for investigating causal relationships.

Purpose of the Study:

• To explore the potential causal effects of autoimmune thyroid dysfunction on brain structure.
• Utilizing genome-wide association study (GWAS) data to analyze these connections.

Main Methods:

• Employed MR analysis with inverse variance weighting (IVW) as the primary method.
• Utilized GWAS data for autoimmune thyroid conditions (hyperthyroidism, hypothyroidism) and brain imaging (cortical area and thickness).
• Conducted sensitivity analyses to ensure the robustness of findings, assessing heterogeneity and pleiotropy.

Main Results:

• Autoimmune hypothyroidism showed causal associations with cortical thickness in the pars triangularis, posterior cingulate, and transverse temporal regions.
• Autoimmune hyperthyroidism was linked to cortical surface area changes in the entorhinal, frontal pole, lateral occipital, lingual, postcentral, precentral, and superior parietal regions.
• Autoimmune hyperthyroidism also demonstrated causal effects on cortical thickness in the entorhinal and posterior cingulate areas, with results consistent across sensitivity analyses.

Conclusions:

• Autoimmune hyperthyroidism and hypothyroidism may causally impact specific areas of the cerebral cortex.
• Further research is warranted to elucidate the precise mechanisms underlying these observed relationships.