A STUDY ON SERUM VITAMIN D AND FERRITIN LEVELS IN FEMALES DIAGNOSED WITH HYPOTHYROIDISM

Abstract

Abstract

Introduction: Thyroid hormones are synthesized and released by the thyroid gland. Vitamin D and thyroid hormones both act through similar nuclear receptors and are expected to affect each other's action. Vitamin D receptors are located in thyroid tissue also and by binding with its receptor, vitamin D may play a role in maintaining a normal thyroid function. Acting as an immune modulator, vitamin D reduces activation of the acquired immune system and its deficiency is suggested to increase the risk of autoimmune diseases including thyroid diseases. Synthesis of thyroid hormones requires an iron containing enzyme, thyroid peroxidase (TPO). Iron inadequacy can affect the proper functioning of this enzyme that further affect the thyroid hormone production. Serum ferritin is an iron storage protein and an index of iron store. This study was conducted to assess association of vitamin D and serum ferritin with thyroid stimulating hormone (TSH) levels in female hypothyroid patients and to compare the levels of vitamin D and ferritin with healthy controls.

Materials and Methods: The present study was hospital based cross sectional study carried out in the department of Biochemistry in collaboration with department of Medicine at SGT Medical college, Gurugram, Haryana. Total 160 female subjects aged between 20-50 years comprising of 80 hypothyroid female subjects as cases and 80 age matched healthy subjects as controls were included in the study. Fasting blood samples were collected from all subjects enrolled in the study and evaluated for thyroid profile (FT3, FT4 and TSH), Vitamin D and ferritin by chemiluminescence immunoassay (CLIA) on MAGLUMI 1000 fully autoanalyser. Results were subjected to statistical evaluation and presented as mean ± SD. P value ≤ 0.05 was considered as statistically significant.

Results: The mean value of TSH of hypothyroid patients was found higher (15.74 ± 13.96 μIU/ml) than that of control group (3.01 ± 0.78 μIU/ml) whereas the mean value of FT3 (2.43 ± 0.55 pg/ml), FT₄ (1.14 ± 0.19 ng/dl), vitamin D (16.84 ± 8.2 ng/ml) and ferritin (36.56 ± 27.82 ng/ml) were found to be reduced in patients with hypothyroidism compared to normal subjects. All the parameters were statistically significant with p value (<0.001).

Conclusion: The present study showed that hypothyroid subjects had significantly lower serum vitamin D and ferritin concentration than healthy controls. There was a significant negative correlation between vitamin D and TSH. Similar negative correlation was found between ferritin and TSH. Hypothyroidism is associated with low serum vitamin D and ferritin levels and their measurement could be beneficial in monitoring of these patients. Along with it regular screening of vitamin D and ferritin levels could be helpful in maintaining their proper levels which will be beneficial in reducing the complications occurring as a consequence of the deficiency.