ESPE Abstracts

Background: The imbalance between oxidant-antioxidant status plays an essential role in the pathogenesis of many autoimmune diseases, including autoimmune thyroid disease (AITD). Studies have described that children with AITD have reduced superoxide dismutase (SOD), glutathione peroxidase (GPx), and significantly low zinc levels. This study assessed the effect of daily zinc supplementation for 12 weeks on thyroid auto-antibodies - thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), and oxidative stress compared to standard therapy.

Methods: This open-labeled, parallel, randomized controlled trial was done in a tertiary care teaching institute in south India. Children aged 3 to 18 years with TPOAb or TgAb positivity were included, and those who received zinc for other illnesses in the preceding three months were excluded. Participants were randomized to receive 25mg of elemental zinc daily for 12 weeks or standard therapy alone. The change in thyroid function tests (thyroid stimulating hormone, free T3, free T4), thyroid auto-antibody titers, and oxidative stress markers (GPx, malondialdehyde, SOD, and total antioxidant capacity) were compared.

Results: 40 children, 20 in each arm, were recruited in the study. We observed a female-to-male ratio of 7:1. Low weight and height for age (Z score < -2) were observed in 5 (12.5%) and 7(17.5%) children, respectively. The median duration of the disease was 2 (0.25,4.25) years. 37(92.5%) children were hypothyroid, two hyperthyroid, and one euthyroid at enrolment. The requirement of levothyroxine dose was 75(50,100) mg per day. 23(72%) had ultrasonographic evidence of thyroiditis. 13 children (32.5%) had associated co-morbidities, most commonly type 1 diabetes mellitus and systemic lupus erythematosus, three (7.5%) each. We did not find any significant change in thyroid function tests, thyroid auto-antibody titers, and oxidative stress markers between the two groups. However, the levothyroxine dose requirement was significantly increased in the control arm compared to the zinc group (P=0.03). Two patients in the zinc group and one in the standard group had normalized thyroid antibodies. The compliance rate of zinc was more than 90% in 13 (65%) patients, between 80-89% in three (15%), 70-79% in three (15%), and one had a compliance rate of 60%. The adverse effects, as described by the participants, were generalized body aches in three (15%), metallic taste in one (5%), nausea in one (5%), and one participant (5%) developed diarrhea with no dehydration. Conclusion: Zinc supplementation did not affect thyroid auto-antibodies and oxidative stress. Zinc-supplemented children did not require escalation in levothyroxine dose.