Age as a major factor associated with zinc and copper deficiencies in pediatric thalassemia

Abstract

Background: Patients with thalassemia encounter increased consumption of zinc (Zn) and copper (Cu) from chronic hemolysis and increased excretion from iron chelation. Iron-enriched diet restriction may result in low Zn and Cu intakes. Recent data on Zn and Cu status among Thai pediatric patients with thalassemia are lacking. This study aimed to identify frequencies and determine risk factors of Zn and Cu deficiencies among patients with thalassemia.

Methods: Patients with transfusion-dependent thalassemia (TDT) receiving iron chelation ≥12 months and nonTDT (NTDT) aged 2-20 years were recruited. Serum Zn and Cu were measured. Dietary intakes were ascertained by interviews.

Results: A total of 209 patients (TDT = 126, NTDT = 83) were enrolled. Zn deficiency seemed to be associated with disease severity as median (IQR) Zn level of TDT was lower than that of NTDT [77 (69-85) vs. 80 (72-88) mcg/dL, p = 0.05], while higher frequency of Zn deficiency was identified in the former (24 % vs. 14 %). In TDT, Zn deficiency was associated with patients >10 years (OR 4.6; 95 %CI 1.1-6.4, p = 0.03), which likely resulted from combined low dietary Zn intake, prolonged exposures to hemolysis and iron chelators. Frequencies of Cu deficiency were similarly low in TDT and NTDT (8% and 7%) with comparable median (IQR) Cu levels of 103 (90-124) and 110 (92-132) mcg/dL, respectively (p = 0.13). Cu levels were inversely associated with age (r=-0.65 and r=-0.62 in TDT and NTDT, respectively; p < 0.001).

Conclusion: Compared with younger patients, Zn and Cu deficiencies were more common among patients with thalassemia >10 years. Age was a major factor associated with both Zn and Cu deficiencies.

Keywords: Cu deficiency; Cu level; Iron chelators; Thalassemia; Zn deficiency; Zn level.