Respiratory symptoms and lung function in young adults with severe α1-antitrypsin deficiency (PiZZ)

Background: Neonatal screening for alpha(1)-antitrypsin (AAT) deficiency was undertaken in Sweden between 1972 and 1974 when 129 infants with severe AAT deficiency (phenotype PiZ) were identified. The cohort has been followed up prospectively. Methods: 124 PiZ subjects, still alive and still living in Sweden, were invited to a follow up examination at about 22 years of age. The check up included a clinical examination, spirometric tests, and a questionnaire on smoking habits and respiratory symptoms. Results: Ninety eight subjects (97 PiZZ and 1 PiZ-) subjects attended the follow up. The mean age of the subjects was 22.5 years (range 19.8-24.8). The mean (SD) forced expiratory volume in 1 second (FEV1) was 98 (14)% predicted, vital capacity (VC) was 103 (14)% predicted, and the mean FEV1/VC ratio was 83 (7)%. Eighty six subjects had previously undergone spirometric tests. The median follow up time was 4.3 years (range 0.9-7.3). The mean annual change in FEV1, (% predicted) was -1.2% (95% Cl-2.1 to -0.3), in VC (% predicted) was -1.5% (95% Cl-2.0 to -0.9), and in the FEV1/VC ratio (%) was -0.3% (95% Cl-0.7 to 0.2). Twenty eight individuals (29%) reported recurrent wheezing. Fifteen subjects (15%) had been diagnosed by a physician as having asthma. Eighteen subjects reported that they had smoked at some time; 10 were current smokers. The mean number of pack years among the ever smokers was 3.4 (range 0.6-10.5). Ten of 18 ever-smokers and 18 of 80 non-smokers reported recurrent wheezing (p<0.01), while exertional dyspnoea was reported by six ever smokers and 11 non-smokers (p<0.05). Lung function test results did not differ significantly between ever smokers and non-smokers. Conclusions: Young PiZ adults have essentially normal lung function, but have a high prevalence of asthma symptoms. Smoking in these individuals is associated with an increased frequency of respiratory symptoms.