The Study the Effect of Vitamin D on Hypothyroidism

Abstract

Background: Vitamin D deficiency or insufficiency is a common worldwide problem. The association between hypothyroidism and vitamin D deficiency is controversial. We aimed to study the effect of vitamin D on thyroid function in hypothyroid patients. Material and Methods: In this case-control randomized clinical trial study, 201 hypothyroid patients reffered to endocrinology clinics in Arak, were randomly classified into two groups.  All patients were taking levothyroxine. Case group received vitamin D 50000 unit weekly and control group received placebo in addition to levothyroxine. After three months, thyroid function tests were repeated and compared with the results of the beginning of the study both intra groups and inter groups by student t test and paired t test analysis. Results: Male/Female ratio in both case and control groups were 0.24 and 0.15 respectively (P=0.1). The prevalence of vitamin D deficiency and insufficiency were 68.7 % (138) and 93.5% (188) and after vitamin D taking were 70% (34.8) and 51.2% (103) respectively.Student t test showed that TSH level in people who received vitamin D had a significant decrease in comparison to the people who received placebo (P<0.05). There were a significant change of TSH level between two groups at vitamin D level 10-30 ng/ml. Conclusion: Most of hypothyroid patients had vitamin D deficiency and vitamin D taking improved thyroid function by TSH suppression in these patients. We recommend the screening for vitamin D deficiency in hypothyroid patients. Although, more researches are needed to clarify molecular explanations of this hypothesis.

Keywords

• Vitamin D
• Hypothyroid
• effect
• TSH