Low plasma zinc concentrations in young infants with cystic fibrosis

Objectives: The purpose of this study was to examine the zinc status of you ng infants with cystic fibrosis before and after the initiation of pancreat ic enzyme therapy. Study design: Cross-sectional data were obtained for infants with cystic fi brosis identified by newborn screening. Plasma zinc concentrations were mea sured and analyzed according to enzyme use at the time of the blood draw. O n a subgroup of infants, zinc concentrations were determined again after se veral weeks with enzyme therapy. Results: Mean (+/-SD) plasma zinc concentration for the infants studied bef ore the initiation of enzyme therapy was 10.4 +/- 2.2 mu mol/L (68.3 +/- 14 .7 mu g/dL) (n = 48), which was significantly lower than the mean for those receiving enzymes for greater than or equal to 2 weeks, 11.8 +/- 2.3 mu mo l/L (77.1 +/- 14.9 mu g/dL) (n = 15) (P = .03). For the group not yet recei ving enzymes, 29% of infants had zinc concentrations in the deficient range . Data were available before and after enzyme therapy for 30 infants and in dicated a mean increase of 1.64 +/- 3.0 mu mol/L (10.7 +/- 19.3 mu g/dL) (P = .005). Conclusions: These data suggest that many of the infants were zinc deficien t at the time of diagnosis. We conclude that zinc should be included among the specific micronutrients given consideration in the management of cystic fibrosis, particularly in infants.