Bidirectional Mendelian Randomization Analysis for Vitamin D and Thyroid Peroxidase Antibody

Area of Science:

• Endocrinology
• Immunology
• Genetics

Background:

• The relationship between vitamin D deficiency and thyroid autoimmunity, specifically thyroid peroxidase antibody (TPOAb) levels, remains debated.
• Understanding this association is crucial for managing autoimmune thyroid diseases.

Purpose of the Study:

• To investigate the potential causal relationship between 25-hydroxyvitamin D [25(OH)D] levels and thyroid peroxidase antibody (TPOAb) concentrations.
• To explore whether vitamin D status influences the development of thyroid autoimmunity.

Main Methods:

• Utilized data from the SPECT-China study (2014-2016), including 10,636 participants.
• Employed Bidirectional Mendelian Randomization (MR) analysis with genetic risk scores (GRS) for 25(OH)D and TPOAb-associated single nucleotide polymorphisms (SNPs).

Main Results:

• A genetic risk score for 25(OH)D was associated with both 25(OH)D levels and TPOAb concentration.
• MR analysis indicated a causal relationship: genetically determined lower 25(OH)D was linked to increased TPOAb concentration (B -0.720, 95% CI -1.429 to -0.012).
• No significant causal association was found between genetically instrumented TPOAb and 25(OH)D levels.

Conclusions:

• Genetically determined lower vitamin D levels are causally associated with increased TPOAb concentration.
• This supports a role for vitamin D insufficiency in the pathogenesis of thyroid autoimmunity within the studied Eastern Chinese population.