Abstract
CONTEX: The first trimester of pregnancy is the most sensitive period in terms of thyroid hypofunction. Iron deficiency has been associated with both thyroid function and thyroid autoimmunity. OBJECTIVE: We aimed to investigate whether iron deficiency is a risk factor for thyroid autoimmunity in non-pregnant women at childbearing age. DESIGN: This cross- sectional study was conducted in non-pregnant women who presented to the Internal Medicine Policlinic between January 2018 and December 2018 in the University of Health Sciences "Fatih Sultan Mehmet" Training and Research Hospital. METHODS: Three hundred fifty-eight non-pregnant women of reproductive ages (203 iron deficient-ID, 155 control) participated in this study. Women with known thyroid disease, currently undergoing treatment for thyroid disease or whose thyroid function tests were outside the reference range were excluded from the study. Blood sample was taken after at least 8-10 hours of fasting for measurement of serum iron (Fe), total iron binding capacity (TIBC), serum ferritin (SF), whole blood count, thyroid function tests (fT4, TSH), anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibody (TgAb). The patients with SF levels ≤ 15 ng/dL were accepted as iron deficiency. RESULTS: The group with ID had higher TSH and lower T4 values that did not reach statistical significance compared to the control group (p=0.101 and p=0.098, respectively). Antibody positivity was more frequent in the ID group than in the control group (35.96% vs. 20.65%, p = 0.002). CONCLUSIONS: Iron deficiency is associated with thyroid autoimmunity and it should be considered as a risk factor for screening thyroid antibody, particularly in pregnancy planning women.