Objective:To determine the influence of polymorphisms of the beta-2 adrenergic receptor
(ADRB2) in triggering exercise-induced bronchospasm (EIB) in adolescents.Methods:The subjects were divided into two groups: present EIB (EIB+) (n=45) and absent
EIB (EIB−) (n=115). The bronchial provocation test with exercise was performed
with a protocol that consisted of walking/running for at least eight minutes at
high intensity, i.e., >85% of maximum heart rate, considering EIB+ as a 10%
decrease in forced expiratory volume in one second (FEV1). The
genotyping of the ADRB2 gene was performed by the Taqman method,
using the Step One Plus system. Independent t-test, Mann–Whitney
and Chi-square tests, as well as Spearman's correlation coefficient were used for
the statistical analysis.Results:Age, body weight, height, FEV1, FVC and FEV1/FVC ratio were
lower in the EIB+ group when compared to EIB− (p<0.05). There
were no significant differences in the proportion of the allele at position 27 and
Arg16Gly and Gln27Glu genotypes between the
EIB+ and EIB− groups (p=0.26; p=0.97 and
p=0.43, respectively). However, there was a trend toward
statistical significance regarding the greater proportion of the Gly16 allele for
the EIB+ when compared to the EIB− group (p=0.08).Conclusions:The presence of polymorphisms associated with the Glu27 allele and
Arg16Gly and Gln27Glu genotypes had no
influence on EIB. However, the statistical trend toward greater frequency of the
Gly16 allele in individuals with EIB+ can be considered
evidence of the influence of polymorphisms of the ADBR2 gene on
EIB in adolescents.