Low vitamin D3 levels and reduced vitamin D receptor (VDR) expression may contribute to the development of thyroid eye disease (TED), according to research presented at the American Academy of Ophthalmology (AAO) 2025 meeting, held in Orlando from October 18 to October 20, 2025.
“Tissue inflammation and abnormal remodeling are the pathognomonic pathways of thyroid eye disease (TED),” the presentation explains. “Vitamin D3, known for its immunomodulatory, antioxidant and antifibrotic properties, plays a vital role in physiological functions and affects general health.”
Chia-An Hsu, MD; Chieh-Chih Tsai, MD; and Yu-Chieh Yang, MD sought to explore the role of vitamin D3 in patients with TED.
Primary orbital fibroblast cultures from 4 patients with TED and 4 normal participants were used to evaluate the VDR. The research team also evaluated the serum levels of 25-hydroxyvitamin D in 48 patients with TED.
The vitamin D3-VDR complex, which belongs to the thyroid hormone receptor subfamily, may play a significant role in the pathogenesis of TED through mechanisms that have yet to be investigated.
The researchers observed a downregulation of VDR gene and protein expression in orbital fibroblasts from patients with TED compared with normal controls. Of the 48 patients, 16 (33.3%) had vitamin D deficiency (20 to <30 ng/mL), and 28 (58.3%) had vitamin D insufficiency (below 20 ng/mL). The average vitamin D3 level was 19.0 ng/mL, the report shows.
“Our in vivo and in vitro studies show low vitamin D3 and VDR in patients with TED,” according to the researchers. “The vitamin D3-VDR complex, which belongs to the thyroid hormone receptor subfamily, may play a significant role in the pathogenesis of TED through mechanisms that have yet to be investigated.”