Assessment of Vitamin D Level in Autoimmune Thyroiditis Patients and a Control Group in the Polish Population

Abstract

Background. Vitamin D, known for its role in calcium-phosphorus homeostasis, is also a significant immunomodulatory factor. Vitamin D deficiency has been reported in some autoimmune disorders. Recently, vitamin D level in autoimmune thyroiditis (HT -Hashimoto's thyroiditis) has become the subject of researchers' interest. Objectives. This study aims to assess vitamin 25-OH-D3 levels in HT patients in comparison to a control group in the Polish population. This would be the first attempt conducted in this region with such poor sunlight exposure. Material and Methods. The group we studied consisted of 62 subjects diagnosed with HT (mean age 49.15 ± 15.51) and 32 healthy controls matched with age and sex (mean age 46.09 ± 14.32). All blood samples were collected in the first quarter of the year to minimize the impact of seasonal fluctuations of vitamin D concentrations. Results. In the HT group the mean vitamin D level was 20.09 nmol/L (SD ± 12.66), compared to 30.31 nmol/L (SD ± 19.49) in the controls, p = 0.014. None of the patients and the controls was vitamin D sufficient (75-125 nmol/L). The deficiency (< 50 nmol/L) was significantly more common among HT patients compared to the controls (61-98.4% vs. 27-84.4%, p = 0.029). Conclusions. In conclusion, we found that serum vitamin D concentration is significantly lower in HT patients in comparison to the control group. This suggests vitamin D deficit as one of the risk factors for HT development. Observed vitamin D level was also low in the control group, therefore wider supplementation in general population should be recommended (Adv Clin Exp Med 2015, 24, 5, 801-806).

Vitamin D and thyroid disorders: a systematic review and Meta-analysis of observational studies

“…Among these, 9 studies were from Turkey [ 26 , 34 , 36 , 37 , 39 , 42 , 43 , 48 , 49 ], 3 each from Saudi Arabia [ 17 , 32 , 35 ], Poland [ 38 , 52 , 59 ], China [ 27 , 28 , 51 ] and Korea [ 54 , 55 , 58 ], 2 each from Egypt [ 50 , 60 ] and Italy [ 40 , 57 ] and one each from Belgium [ 25 ], Canada [ 33 ], Brazil [ 44 ], Japan [ 47 ], India [ 45 ], Sweden [ 46 ], Thailand [ 53 ], Greece, United States [ 56 ], and Ukraine [ 31 ]. Among the 35 studies, 29 recruited both genders [ 25 , 27 – 32 , 34 – 41 , 43 – 46 , 48 – 56 , 58 ], 4 only women [ 17 , 42 , 47 , 57 ], and 2 studies did not report the gender [ 26 , 33 ]. Eighteen studies mentioned BMI [ 27 , 28 , 30 , 31 , 33 , 35 , 36 , 40 , 45 , 47 , 50 – 53 , 55 – 58 ] and 26 studies pointed to the time of ...…”

“…Inconsistencies in terms of the season of sample collection could also influence our final results. Besides, it has been proven that the bioavailability of vitamin D diminishes among overweight/obese individuals [ 65 ]; however, most of the included articles disregarded BMI as a confounding factor and probable source of heterogeneity [ 17 , 18 , 25 , 26 , 29 , 32 , 34 , 37 – 39 , 41 – 44 , 46 , 48 , 49 , 54 ].…”

Vitamin D and Autoimmune Thyroid Disease—Cause, Consequence, or a Vicious Cycle?

“…Tamer et al identified lower 25(OH)D levels in individuals with HT versus control subjects, with a tendency for a higher prevalence of deficiency in patients with hypothyroidism than in those in euthyroidism [51]. Studies in other populations corroborated the association between lower levels of 25(OH)D and the risk of HT, namely Bozkurt et al 2013 [52]; Mansournia et al 2014 [53]; Vondra et al 2015 [7]; Maciejewski et al 2015 [54]; Kim D et al 2016 [55]; Giovinazzo et al 2017 [56]; Ke et al 2017 [57]; and Pergola et al 2018 [58].…”

Autoimmune Diseases and Vitamin Deficiencies on Autoimmune Thyroiditis, With Special Attention to Hashimoto Thyroiditis

“…In recent years, scientists have also been interested in vitamin D deficiency in Hashimoto patients [27,28]. Numerous studies indicate a low content of this vitamin in the blood serum of patients with lymphocytic thyroiditis.…”

“…Most of the available studies indicated an increase in vitamin D deficiency and its decreased concentration in the group of people with Hashimoto compared to the control group. The differences relate to the correlation of vitamin D concentration in relation to the hormonal activity of the thyroid gland and the activity of the autoimmune process in the assessment of antithyroid antibodies (Table 2) Table 2: A review of studies assessing the relationship between vitamin D levels and Hashimoto's disease [27,28,30,34,35,38].…”