Plasma zinc and growth status in preadolescent children with cystic fibrosis

Abstract

Objective: To investigate plasma zinc status in relation to dietary and supplemental zinc intake, growth and pulmonary status in preadolescent children with cystic fibrosis (CF) and pancreatic insufficiency (PI).

Methods: Fasting plasma zinc was assessed in children (age, 8-11 years) with CF and PI. Food (7-day weighed records) and supplemental zinc intake, serum alkaline phosphatase and albumin, pulmonary function (spirometry), coefficient of fat absorption (%COA, 72-hour fecal fat) and growth status [height adjusted for genetic potential (AHAZ), weight (WAZ) and BMI Z scores (BMIZ)] were assessed.

Results: For the 62 children (32 males), mean plasma zinc (+/-SD) was 16.8 +/- 3.1 micromol/L (110 +/- 20 ug/dL). Sixty-five percent of the subjects had levels above the study reference range of 9.2 to 15.3 micromol/L (60-100 ug/dL); no subjects had low zinc levels. Median (range) total daily zinc intake was 279% (83-988%) recommended dietary allowance, growth status was suboptimal (mean +/- SD: AHAZ, -0.8 +/- 1.0; WAZ, -0.5 +/- 1.2; BMIZ, -0.2 +/- 1.1), and forced expiratory volume at 1 second (FEV1) was 92 +/- 13% predicted. Plasma zinc was not correlated with growth, pulmonary or alkaline phosphatase status. Plasma zinc was correlated with serum albumin (r = 0.25, P < 0.05) and was inversely correlated with coefficient of fat absorption (as %; r = -0.30, P = 0.02).

Conclusions: Under current patterns of care in CF Centers, total zinc intake and plasma zinc status were adequate. These findings suggest that zinc was not a limiting micronutrient for preadolescent children with CF and PI and mild-to-moderate lung disease, and not likely contributing to their suboptimal growth status.