Objective: Thyroid hormones directly or indirectly, through erythropoietin, stimulate growth of erythroid colonies. Anemia is often the first sign of hypothyroidism. Hypothyroidism can lead to a wide variety (%2060) of anemic disorders. Numerous mechanisms are involved in the pathogenesis of these anemias which can be microcytic, macrocytic and normocytic. Microcytic anemia is usually ascribed to malabsorption of iron and loss of iron by menorrhagia. Macrocytic anemia is caused by malabsorption of vitamin B12, folic acid, as seen in pernicious anemia and in inadequate nutrition. Normocytic anemia is characterized by reticulopenia, hypoplasia of erythroid lineage, decreased level of erythropoietin, mainly regular erythrocyte survival. We designed this study to investigate the anemia frequency and if present, etiology of anemia in hypothyroid patients.
Research design and methods: Overt hypothyroid 100 patients, subclinical hypothyroid 100 patients and 200 healthy controls enrolled in this study.
Results: Anemia prevalence was 43% in the hypothyroid group, 39% in the subclinical hypothyroid group and 26% in the control group which was statistically significant (P=0.003 and P=0.021 respectively related to controls). There was no difference between the hypothyroid groups in terms of anemia. Vit B12, Fe, folic acid were similar between the groups.
Conclusions: According to our findings, chronic disease anemia is the most common type of anemia in hypothyroid patients similarly with the literature. Suspicion of hypothyroidism should be considered in every case of anemia with uncertain etiology.