TRACE METALS IN CYSTIC FIBROSIS

Abstract

Serum zinc and copper concentration, 24 hrs urinary zinc and copper excretion, plasma selenium and red blood cell glutathione peroxidase activity were measured in 13 cystic fibrosis patients aged 6 to 15 years. The mean serum zinc value +/- S.D. (17.3 mumol/l +/- 4.6) did not differ from that of the control group (17.9 mumol/l +/- 3.1). Urinary zinc excretion in 12 out of 13 patients was within the normal range (1.53-13.8 mumol/24 hrs). The mean serum copper +/- S.D. (23.8 mumol/l +/- 4.2) was not significantly elevated as compared to the value found in the control group (19.2 mumol/l +/- 3.5), but 4 children, including 1 with documented portal hypertension, showed an urinary copper excretion greater than 0.94 mumol/24 hrs (normal: 0.16-0.80 mumol/24 hrs). Mean plasma selenium +/- S.D. (0.84 mumol/l +/- 0.25) was significantly reduced as compared to the control group (1.0 mumol/l +/- 0.15) (p less than 0.05). The correlation between selenium concentration and RBC glutathione peroxidase activity was significant (p less than 0.01). A negative correlation was also found between plasma selenium and 24 hrs faecal fat excretion (p less than 0.05). It is concluded that CF children with severe dysfunction of the exocrine pancreas are at increased risk to develop symptoms of subclinical or manifest zinc and/or selenium deficiency. Appropriate supplementation should therefore systematically be considered.