Serum zinc concentrations in cystic fibrosis patients aged above 4 years: a cross-sectional evaluation

Abstract

Aim: Assess the risk of zinc (Zn) deficiency in the older cystic fibrosis (CF) population.

Method: Cross-sectional investigation of all CF patients above the age of 4 followed at the Ghent University center between 2002 and 2003. Data on age, weight, height z-score, pancreatic and pulmonary functions, chronic Pseudomonas infection, and CF transmembrane conductance regulator (CFTR) mutations were collected. Serum Zn, vitamins (vit) A and E, retinol-binding protein (RBP), albumin, sedimentation rate, total IgG, and cholesterol were determined. Serum Zn was compared with a local healthy control group (Van Biervliet et al., Biol Trace Elem Res 94:33-40, 2003) and with literature data (Hotz C, et al. Am J Clin Nutr 78:756-764, 2003).

Results: 101 patients (median age 16 years) were included. There was no difference in serum Zn concentration between CF patients and controls. In CF patients no difference in serum Zn concentration between pancreatic-sufficient or pancreatic-insufficient patients was seen. Serum Zn was not associated to nutritional status or height z-score. A significant association serum Zn to serum albumin (p < 0.0005) and to vit A (p < 0.01) was seen. No associations of serum Zn to serum vit E, RBP, cholesterol, or CFTR were present, but there is a significant association serum Zn to forced vital capacity (p < 0.01). Serum Zn was not associated to inflammatory parameters or chronic Pseudomonas infection.

Conclusion: Comparison of CF patients with local controls revealed no significant differences. However, because persisting steatorrhea increases Zn loss (Easley et al., J Pediatr Gastroenterol Nutr 26:136-139, 1998) and 12.6% of our population has a serum Zn below the p value of 2.5 of the NHANES II study (Hotz C, et al. Am J Clin Nutr 78:756-764, 2003), there could remain an increased risk of Zn deficiency in some CF patients. Furthermore, the association with pulmonary function needs more investigation.