Plasma Zinc and Growth Status in Preadolescent Children with Cystic Fibrosis

Abstract

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). 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. 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). 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.