Vitamin A deficiency alters airway resistance in children with acute upper respiratory infection

Objective To assess whether vitamin A deficiency alters the recovery of total respiratory resistance (TRR) following acute upper respiratory tract infection (URI). Methods This is a case control study of children, age 4–6 years and grouped as: URI, (n = 74), URI and wheezing, (URI‐wheezing, n = 52), and healthy controls (n = 51). Vitamin A and total respiratory resistance (TRR) were assessed using the modified relative dose response (MRDR) and forced oscillometry, respectively. Results Children with URI and URI‐wheezing had lower retinol, 32.4 ± 13.12 and 18.3 ± 6.83 µg/dl respectively, compared to controls, 56.9 ± 29.82 µg/dl (ANOVA, P  < 0.001). The MRDR was elevated in children in the URI or URI‐wheezing groups 0.066 ± 0.045 and 0.021 ± 0.021, respectively, compared to controls 0.007 ± 0.006 (ANOVA, P  < 0.0001). The TRR in the URI and URI‐wheezing groups differed from controls. During convalescence, the TRR failed to decline in the URI‐group only when the MRDR was >0.06. In the URI‐wheezing group, TRR declined independently of retinol and MRDR. Conclusion Vitamin A contributes to preservation of airway function during and in recovery after upper respiratory infection in children. Pediatr Pulmonol. 2013; 48:481–489. © 2012 Wiley Periodicals, Inc.