The effects of iron deficiency anemia on the thyroid functions

Abstract

Objectives: The aim of the present study was to investigate the effect of iron deficiency anemia and iron treatment on the thyroid functions. Materials and methods: In this study, 42 patients and 38 healthy individuals were studied. Iron deficiency anemia was diagnosed by measurement of serum ferritin and complete blood counts. Free Triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine, total thyroxine, thyroid stimulating hormone (TSH) and cortisol levels were measured in blood samples before treatment and after two months of treatment with iron in patients group and after 12 hours of starvation in healthy controls. Results: Before iron treatment, secondary hypothyroidism (35.7%) and subclinical hypothyroidism (16.6%) were found in patient group. Before the treatment TSH levels in the patient group were higher than the control group (p=0.001). FT3 values were not different between patient and the control groups (p>0.05). Before the treatment FT4 levels were significantly lower than the control group (p

Keywords

• Iron deficiency, anemia, thyroid functions, secondary and subclinical hypothyroidism, iron supplementation

Demir eksikliği anemisinin tiroid fonksiyonları üzerine etkisi

Öz

Amaç: Bu çalışmanın amacı demir eksikliği anemisinin tiroid fonksiyonları üzerine etkisi ve demir tedavisi sonrası değişiklikleri belirlemektir. Gereç ve yöntem: Bu çalışma, 42 hasta ve 38 sağlıklı birey ile yapıldı. Demir eksikliği anemisi tanısı serum ferritin ve tam kan sayımı yapılarak kondu. Hasta grubunda tedavi öncesi ve iki aylık tedavi sonunda ve kontrol grubunda ise 12 saat açlıktan sonra kan örnekleri alınarak serbest triiyodotironin (ST3), serbest tiroksin (ST4), total triiyodotironin (TT3), total tiroksin (TT4), tiroid stimule edici hormon (TSH) ve kortizol değerleri çalışıldı. Bulgular: Hasta grubunda demir tedavisi öncesi, olguların %35.7\'sinde sekonder ve %16.6\'sında subklinik hipotiroidi bulundu. Hasta grubunda tedavi öncesi, TSH düzeyi kontrol grubuna göre anlamlı düzeyde yüksekti (p=0.001). ST3 düzeyleri hasta ve kontrol grupları arasında farklı değildi (p>0.05). Tedavi öncesi ST4 düzeyleri, kontrol grubuna göre, anlamlı düşüktü (p

Anahtar Kelimeler

• Demir eksikliği, anemi, tiroid fonksiyonları, sekonder ve subklinik hipotiroidi, demir tedavisi

References

1. Prasad AN, Prasad C. Iron deficiency; non-hematological manifestations. Prog Food Nutr Sci 1991;15:255-83.
2. Docter R, Krenning EP, de Jong M, Hennemann G. The sick euthyroid syndrome: changes in thyroid hormone serum pa- rameters and hormone metabolism. Clin Endocrinol (Oxf) 1993; 39:499-518.
3. Chopra IJ, Hershman JM, Pardridge WM, Nicoloff JT. Thy- roid function in nonthyroidal illnesses. Ann Intern Med 1983; 98:946-57.
4. Chen SCH, Shirazi MRS, Orr RA. Triiodothyronine (T3) and thyroxine (T4) levels in iron-deficient, hypertriglyceridem- ic rats. Nutr Res 1983; 3: 91-106.
5. Beard J, Green W, Miller L, Finch C. Effect of iron-deficien- cy anemia on hormone levels and thermoregulation during cold exposure. Am J Physiol 1984; 247: 114-9.
6. Brigham DE, Beard JL. Effect of thyroid hormone re- placement in iron-deficient rats. Am J Physiol 1995; 269: 1140-7.
7. Dillman E, Gale C, Green W, Johnson DG, Mackler B, Finch C. Hypothermia in iron deficiency due to altered triiodothy- ronine metabolism. Am J Physiol 1980; 239: 377-81.
8. Drew Provan. ABC of Clinical Haematology, 2nd edn. Lon- don: BMJ Books, 2003: 1-5.

9. Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA 2004; 291: 228-38.
10. Bakiri F. TSH determination in central hypothyroidism. Ann Endocrinol 1999; 60: 422-6.
11. Roti E, Minelli R, Gardini E, Braverman LE. The use and misuse of thyroid hormone. Endocr Rev 199314: 401-23.
12. Beard JL, Borel MJ, Derr J. Impaired thermoregulation and thyroid function in iron-deficiency anemia. Am J Clin Nutr 1990; 52: 813-9.
13. Beard J, Finch CA, Green WL. Interactions of iron defi- ciency, anemia, and thyroid hormone levels in response of rats to cold exposure. Life Sci 1982; 30: 691-7.
14. Beard J. Feed efficiency and norepinephrine turnover in iron deficiency. Proc Soc Exp Biol Med 1987; 184: 337-44.
15. Tang F, Wong TM, Loh TT. Effects of cold exposure or TRH on the serum TSH levels in the iron-deficient rat. Horm Me- tab Res 1988; 20: 616-9.
16. Beard JL, Tobin BW, Smith SM. Effects of iron repletion and correction of anemia on norepinephrine turnover and thyroid metabolism in iron deficiency. Proc Soc Exp Biol Med 1990; 193: 306-12.
17. Hess SY, Zimmermann MB, Arnold M, Langhans W, Hur- rell RF. Iron deficiency anemia reduces thyroid peroxidase activity in rats. J Nutr 2002; 132: 1951-5.
18. Gunduz Z, Kumandas S, Kurtoglu S, Uzum K. Effect of Iron Deficiency Anemia in thyroid hormones. Turk J Med Sci 1992; 10: 205-9.
19. Beard J, Tobin B, Green W. Evidence for thyroid hormone deficiency in iron-deficient anemic rats. J Nutr 1989; 119: 772-8.
20. Kantrowitz LB, Peterson ME, Melian C, Nichols R. Serum total thyroxine, total triiodothyronine, free thyroxine, and thyrotropin concentrations in dogs with nonthyroidal dis- ease. J Am Vet Med Assoc 2001; 219: 765-9.
21. Hamblin PS, Dyer SA, Mohr VS, et al. Relationship be- tween thyrotropin and thyroxine changes during recovery from severe hypothyroxinemia of critical illness. J Clin En- docrinol Metab 1986; 62: 717-22.
22. Kokei S, Inoue T, Iino S. Serum free thyroid hormones and response of TSH to TRH in nonthyroidal illnesses. Nippon Naibunpi Gakkai Zasshi 1986; 62:1231-43.
23. Duntas LH, Papanastasiou L, Mantzou E, Koutras DA. In- cidence of sideropenia and effects of iron repletion treat- ment in women with subclinical hypothyroidism. Exp Clin Endocrinol Diabetes 1999; 107: 356-60.
24. Brent GA, Hershman JM. Thyroxine therapy in patients with severe nonthyroidal illnesses and low serum thyroxine concentration. J Clin Endocrinol Metab 1986; 63: 1-8.
25. Utiger RD. Altered thyroid function in nonthyroidal illness and surgery. To treat or not to treat? N Engl J Med 1995; 33: 1562-3.