Anemia in thyroid diseases

352 Epidemiology Both anemia and thyroid dysfunction are common disorders.4-6 The peak incidence of anemia is around 10% in the female population of child-bearing age, as well as in the elderly population.7,8 A recent large cohort population-based study demonstrated that in the population at an estimated mean age of 59.4 years, the prevalence of thyroid function disturbances was 5.0%, while anemia was present in 5.9% of the studied patients. In a study by M’Rabet-Bensalah et al,1 anemia was most frequent in overt hyperthyroidism (14.6%) and was less often observed in overt hypothyroidism (7.7%).1 Omar et al9 reported even higher incidence of anemia accompanying hyperthyroidism and hypothyroidism: 40.9% and 57.1%, respectively. Hemoglobin concentrations were reported to be significantly lower both in women with increased and in those with decreased thyroid-stimulating hormone (TSH) levels, when compared with euthyroid women.10 In fact, in a study on patients with Graves hyperthyroidism, one third of the population presented anemia, while restoration of Introduction Anemia is a common, although frequently underestimated, clinical condition accompanying thyroid diseases.1 Despite the fact that anemia and thyroid dysfunction often occur simultaneously, the causative relationship between the disorders remains ambiguous. Different forms of anemia might emerge in the course of thyroid dysfunction. Normocytic anemia is the most common, while microcytic and macrocytic anemias are less prevalent.2,3 There are abundant literature data on the association between thyroid status and anemia. However, the available studies often report conflicting results, and there is limited number of large cohort studies. Both anemia and thyroid disease, due to their high prevalence and close interrelation, are significant clinical problems often encountered by practitioners. Therefore, this review aimed to provide a comprehensive summary of data on the prevalence, potential mechanisms, and therapy of anemia in the course of thyroid diseases from the clinical and pathogenetic perspectives. REVIEW ARTICLE