Comparison of Vitamin D and Zinc Deficiency in Hypothyroid Patients and Healthy Subjects in Birjand, Iran during 2016

Background and Objective: Vitamin D deficiency is a global health problem. The role of vitamin D as an immunomodulator has been studied and its prophylactic effect for autoimmune diseases has been recently noticed. The relation between vitamin D deficiency and hypothyroidism esp. autoimmune hypothyroidism is not clear. Moreover, there is considerable evidence about changes in blood trace elements such as zinc due to hypothyroidism which can lead to various body systems dysfunction. The present study was aimed to compare the prevalence of Vitamin D and Zinc deficiency between hypothyroid patients and healthy controls. Materials and Methods: In this case–control study, 50 hypothyroid patients referred to endocrinology clinic of Vali_e_Asr hospital, Birjand, Iran as cases and 50 age, sex and BMI matched healthy people as controls were enrolled. The study protocol had been previously confirmed by the Ethics Committee of Birjand University of Medical Sciences (Ir.bums.REC.1395.282). After obtaining informed consent, blood samples from participants and sent to laboratory for Vitamin D, Ca, Zinc, TSH and Anti TPO measurement. Data were analyzed using SPSS version 19 with the help of independent T test, Mann Whitney test and Pearson and Spearman Correlation tests. P<0.05 was considered statistically significant.Findings: 16 percent of cases and 20 percent of controls were male. Mean ± SD of age in case and control groups was 45.66±6.39 and 44.20±7.84 years, respectively. Mean ± SD of BMI in case and control was 26.11±3.19 and 25.69±3.15, respectively. There was no significant difference regarding sex, age and BMI between case and control groups. Mean serum TSH was significantly different between 2 groups (P<0.001). 76 percent of cases and 12 percent of controls were Anti-TPO positive (P<0.001). Mean ± SD of Serum Vitamin D in cases and controls was 16.61±9.52 and 23.26±15.57 ng/ml, respectively. Mean ± SD of Serum Calcium in cases and controls was 9.16±0.45 and 9.37±0.52 mg/dl, respectively. Mean ± SD of Serum zinc in cases and controls was 86.16±10.78 and 96.57±21.25 μg/dl, respectively. The difference regarding Vitamin D, Calcium and Zinc between groups was statistically significant (P=0.012, 0.040 and 0.007, respectively). 88 percent of cases and 68 percent of controls had vitamin D deficiency (P=0.016). 16 percent of cases and 4 percent of controls had Zinc deficiency (P=0.046). In cases, TSH was significantly and inversely correlated with vitamin D (r=-0.530, P<0.001) and calcium (r=-0.515, P<0.001) and also significantly and directly with Anti-TPO (r=0.628, P<0.001). Anti-TPO was significantly and inversely correlated with vitamin D (r=-0.286, P=0.044).Conclusion: Our results showed that serum vitamin D levels and the prevalence of vitamin D and Zinc deficiency are significantly different in comparison of hypothyroid and healthy patients. These results can be in favor of vitamin D and Zinc deficiency pathophysiologic role in thyroid diseases.

Keywords:

Vitamin D , Zinc , Hypothyroidism , Hashimoto’s Disease , Autoimmune Disease