Association of Vitamin D Levels and Systemic Inflammation in Patients with Hashimoto's Thyroiditis

Background/Objectives: Vitamin D is an important regulator of immune and inflammatory processes, while its deficiency is frequently observed in Hashimoto's thyroiditis (HT). The relationship between Vitamin D and systemic inflammation in HT remains insufficiently understood, particularly across different disease stages.

Methods

We used the Olink Target 96 Inflammation panel to investigate this association. Inflammatory proteins and serum 25(OH)D levels were measured in 257 HT patients and 173 controls from the CROHT biobank. Participants were categorized as Vitamin D deficient (<20 ng/mL) or non-deficient (≥20 ng/mL), with HT patients further stratified as euthyroid, hypothyroid, or levothyroxine-treated. Associations between 25(OH)D and 92 inflammatory proteins were assessed using multivariable linear regression adjusted for age, sex, BMI, smoking, and season of blood sampling, followed by interaction testing and meta-analysis.