The bronchial challenge test using isocapnic hyperventilation of cold air (
IHCA) was used to evaluate bronchial responsiveness in 63 offspring of mult
iple pregnancies when they were 8-15 years old. At birth, 27 (43%) children
had had intrauterine growth retardation (IUGR, birth weight <-2 SD, or bir
th weight difference between twin pairs >1.3 SD). The median birth weight w
as 2,050 g (range, 800-3,150), and the median gestational age was 35 weeks
(range, 28-38). None of the children had asthma or suffered from asthma-lik
e symptoms. In the interpretation of the IHCA test, a fall of 9% or more in
the forced expiratory volume in 1 sec (FEV,) was considered as abnormal, a
nd these children were classified as "cold air responders."
The number of responders was 16 (25%); their baseline FEV1/forced vital cap
acity ratio (FEV1/FVC) and forced expiratory flow between 25-75% FVC (FEF25
-75), but not FEV, were significantly lower than the corresponding values i
n nonresponders. No differences were found in perinatal or neonatal factors
between responders or nonresponders. Eight (30%) of the 27 IUGR and 8 (22%
) of the 36 appropriate for gestational age (AGA) children were IHCA respon
ders. In particular, IUGR was not correlated with maximal FEV, falls follow
ing the IHCA test. Respiratory infections after the neonatal period were eq
ually common in IUGR and AGA children; but infections were associated with
subsequent IHCA responsiveness. Adenoidectomy, tonsillectomy, and/or myring
otomy had been performed significantly more often in the responders than in
the nonresponders. At least one of the above invasive procedures had been
performed in 20 (32%) of the children; this group was termed the "ENT tear,
nose, throat) surgery group." Fifty-six percent of the responders, but onl
y 26% of the nonresponders, belonged to the ENT surgery group (P = 0.02).
We conclude that intrauterine growth retardation or prematurity is not asso
ciated with abnormal cold air responsiveness in the IHCA test. (C) 1999 Wil
ey-Liss, Inc.