VITAMIN-A STATUS IN ACUTE EXACERBATIONS OF CYSTIC-FIBROSIS

Vitamin A is an essential nutrient for epithelial cell maintenance and repair, and it is known that infectious stresses may depress plasma v itamin A concentrations. Patients with cystic fibrosis are at risk for vitamin A deficiency because of fat malabsorption as well as for the inflammatory stresses of pulmonary exacerbations of their underlying d isease. We therefore hypothesized that acute pulmonary exacerbations o f CF would depress plasma retinol concentrations, and that these conce ntrations would return to baseline values when clinical symptoms impro ved. We prospectively studied 35 CF patients (mean age: 24.2 y) consec utively admitted with pulmonary exacerbations. Plasma retinol, vitamin E, retinol binding protein (RBP), and C-reactive protein (CRP) concen trations were measured on hospital admission and discharge. Dietary in take was measured by using a semiquantitative food-frequency questionn aire. Regression analysis was used to identify significant clinical an d laboratory correlates of retinol concentrations. On admission, mean (+/- SD) concentrations of plasma retinol were 1.14 +/- 0.5 mu mol/L c ompared with 1.70 +/- 0.6 mu mol/L on discharge (P = 0.0001). Of 35 su bjects, 8 (22.9%) had plasma retinol concentrations considered to be i n the deficient range (< 0.70 mu mol/L). Concurrently, mean concentrat ions of plasma RBP increased during hospital admission (from 1.46 to 2 .24 mu mol/L, P = 0.003), and the mean CRP concentration declined (fro m 25.7 to 9.8 mg/L, P = 0.002). Significant positive correlations were found between plasma retinol concentrations at admission and age, wei ght, body mass index, triceps-skinfold thickness percentile, midupper arm circumference percentile, plasma vitamin E, and RBP concentration, thus suggesting that better-nourished patients had more optimal vitam in A status. At admission, plasma retinol concentrations were negative ly correlated with maximum body temperature and CRP concentrations, wh ich indicated that the body's acute-phase response was associated with the depression in retinol concentrations. We conclude that plasma ret inol concentrations are depressed in acute pulmonary exacerbations of cystic fibrosis, and that concentrations considered to be in the defic ient range are common. Vitamin A metabolism during acute inflammatory stress deserves further study.