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.