Study of Vitamin D Level and Vitamin D Receptor Polymorphism in Hypothyroid Egyptian Patients

Abstract

Purpose. The current study aimed at assessing vitamin D level and vitamin D receptor polymorphism in hypothyroid Egyptian patients and its effect on hypothyroidism and thyroid morphology, also to find a causal relation between vitamin D and hypothyroidism. Methods. This case-control study was conducted on 35 hypothyroid patients and 35 matched unrelated healthy controls. Total serum 25-hydroxyvitamin D3 and thyroid antibodies were measured using a human ELISA kit. Genotyping was performed by using real-time PCR. HOMA-IR was also calculated (fasting insulin in mIU/L × fasting glucose in mg/dL/405). All subjects were assessed for thyroid morphology by thyroid ultrasonography. Results. Vitamin D level was lower in hypothyroid patients than in control subjects. Vitamin D was also inversely related to TSH, HOMA-IR, and levels of anti-TG and anti-TPO. VDR polymorphism (Fok1 and Apa1) had no relation to TSH or vitamin D levels in both patients and control groups. Low vitamin D levels were associated with increased thyroid vascularity and nodularity; furthermore, vitamin D was inversely proportional to thyroid gland volume. Correlation of HOMA-IR with the levels of both anti-TG and anti-TPO in the 70 subjects proved that HOMA-IR was positively correlated to both antibodies. Conclusion. This study confirmed the association of vitamin D deficiency with hypothyroidism, thyroid autoimmunity, increased volume, nodularity, and vascularity of thyroid gland in hypothyroid patients as well as increased HOMA-IR. It proved the association between HOMA-IR and thyroid autoimmunity. The study proved no association between VDR polymorphisms (Fok1 and Apa1) with either vitamin D levels or TSH levels.

Immunomodulatory Effects of Vitamin D in Thyroid Diseases

“…Three years later, Camurdan et al observed that hypovitaminosis D rate was higher in children with HT compared to control group (73.1% vs. 17.6%) and confirmed the inverse association between 25(OH)D3 levels and TPOAb titer in their pediatric population [71]. This inverse correlation was substantiated in the following studies: [66,[72][73][74][75]. Furthermore, different clinical studies showed that the prevalence of HT in patients with hypovitaminosis D was significantly higher than that documented in subjects with sufficient vitamin D levels, particularly among children, elderly subjects, and pre-menopausal women [64,71,[76][77][78][79][80][81].…”

Association between vitamin D deficiency and hypothyroidism: results from the National Health and Nutrition Examination Survey (NHANES) 2007–2012

“…In our study, we found that the odds of developing hypothyroidism were significantly higher among patients with intermediate and deficient levels of vitamin D. Kim 38 reported in Korean population that vitamin D deficiency is highly prevalent in autoimmune Hashimoto’s thyroiditis presenting with overt hypothyroidism than subclinical hypothyroid variants [ 38 ]. Studies have shown that a reciprocal relationship exists between serum TSH and vitamin D levels in hypothyroid subjects [ 38 , 39 ]. ElRawi et al reported vitamin D deficient hypothyroid subjects have higher insulin resistance which significantly correlated with higher anti-thyroid antibodies, anti-TPO and anti-Tg [ 39 ].…”

“…Studies have shown that a reciprocal relationship exists between serum TSH and vitamin D levels in hypothyroid subjects [ 38 , 39 ]. ElRawi et al reported vitamin D deficient hypothyroid subjects have higher insulin resistance which significantly correlated with higher anti-thyroid antibodies, anti-TPO and anti-Tg [ 39 ]. However, they did not observe any significant vitamin D receptor polymorphism in subject vs control suggesting that correction with vitamin D supplements may possibly have a therapeutic benefit in correcting thyroid status.…”

Relationship between vitamin D receptor gene polymorphisms and vitamin D levels in children

“…In Turkey, no significant association was found between Vitamin D levels and FokI polymorphism among major depression patients [31]. In a study evaluating 84 pediatric patients with a diagnosis of Hashimoto's Thyroiditis, VDR polymorphisms and vitamin D levels were not related [32,33].…”