Short- and long-term uses of calcium acetate do not change hair and serum zinc concentrations in hemodialysis patients

Calcium acetate (CaAc) acutely decreases absorption of concomitantly admini stered zinc gluconate (Hwang et al., AJKD 1992), but its long-term effect o n zinc metabolism has not been studied. This study is intended to elucidate whether use of CaAc as phosphate binder on a daily basis affects zinc stat us in hemodialysis (HD) patients. Effects of CaAc on serum zinc were studie d in 44 HD patients for 8 weeks (short-term). In 10 of these patients, the changes of serum and hair zinc were followed for 8 months (long-term). The daily dose of CaAc contained 25.35 mmol elemental calcium. Serum and hair z inc concentrations were measured by atomic absorptiometry. Our results were as follows. (i) in the short-term study, serum zinc concentrations did not show a significant difference compared to the baseline; (ii) in the long-t erm study, serum zinc concentrations showed no significant difference betwe en different time points (11.0+/-0.5 in the beginning, 11.9+/-0.4 after 2 m onths, 11.4+/-0.4 after 4 months and 11.3+/-0.5 mu mol/L after 8 months, n= 10). However, these values were all significantly lower than in the normal controls (15.7+/-0.5 mu mol/L, n=16); (iii) hair zinc content was not signi ficantly different from the baseline level (2.7+/-0.1 in the beginning, 2.4 +/-0.1 after 2 months, 2.6+/-0.2 after 4 months, 3.1+/-0.1 mu mol/g hair, a nd from that of normal controls, 2.7+/-0.2 mu mol/g hair). In conclusion, d aily application of CaAc does not significantly interfere with zinc absorpt ion and storage in HD patients. However, the comparable hair zinc content i n the presence of decreased serum zinc concentrations indicates that the me tabolic processing of zinc in HD patients is different from that of normal individuals.