Background We have previously reported a relationship between increased airway responsiveness (AR) in infancy and reduced childhood lung function.
Objective The current study aimed to determine whether the Arg16Gly polymorphism of the β2 adrenoceptor (β2AR) gene was important to this relationship.
Methods A cohort that initially numbered 253 individuals underwent assessments of AR and lung function aged 1 month, 6 and 11 years; genotyping for polymorphisms of the β2AR was performed.
Results At 1 month of age, the genotype homozygous Arg16 (n=24) was associated with a mean increase in log dose–response slope (AR) of 0.27 [95% confidence interval (CI) 0.07, 0.49] compared with the genotype homozygous Gly16 (n=58), P=0.01. At 11 years of age, the genotype homozygous Arg16 (n=35) was associated with a mean reduction in the percentage of forced expiratory volume in 1 s of 5.3% [95% CI 0.3, 10.2] compared with the genotype homozygous Gly16 (n=65), P=0.03. There was no association between the Arg16Gly polymorphism and atopy or diagnosed asthma. However, nine of 69 individuals with the genotype homozygous Gly16 were admitted to hospital with asthma compared with five out of 111 individuals with the remaining genotypes (P<0.05).
Conclusion The Arg16Gly polymorphism may be important to the association between increased AR in infancy and reduced lung function in childhood and may also be a determinant of asthma severity in children but not asthma per se.