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Respiratory symptoms and lung function in young adults with severe alpha(1)-antitrypsin deficiency (PiZZ)
1Department of Respiratory Medicine, Lund University, University Hospital, Malmö, Sweden. eeva.piitulainen@lung.mas.lu.se
Insights
Individuals with alpha(1)-antitrypsin (AAT) deficiency (PiZ phenotype) show normal lung function in early adulthood but a high rate of asthma symptoms. Smoking exacerbates respiratory issues in this group.
Area of Science:
- Pulmonology
- Genetics
- Public Health
Background:
- Neonatal screening for alpha(1)-antitrypsin (AAT) deficiency identified 129 infants with severe AAT deficiency (PiZ phenotype) in Sweden (1972-1974).
- This cohort has undergone prospective follow-up since identification.
Purpose of the Study:
- To evaluate the long-term respiratory health of individuals with severe AAT deficiency (PiZ phenotype).
- To assess lung function and respiratory symptoms in young adults identified through neonatal screening.
Main Methods:
- A follow-up examination was conducted on 124 surviving PiZ subjects residing in Sweden at approximately 22 years of age.
- Assessments included clinical examination, spirometry (FEV1, VC, FEV1/VC ratio), and questionnaires on smoking habits and respiratory symptoms.
Main Results:
- Ninety-eight subjects (mean age 22.5 years) attended the follow-up, showing mean lung function parameters within normal predicted ranges (FEV1 98%, VC 103%).
- Annual decline in FEV1 and VC was observed (-1.2% and -1.5% predicted per year, respectively).
- A high prevalence of asthma symptoms (29% recurrent wheezing, 15% physician-diagnosed asthma) was noted. Smoking was associated with increased respiratory symptoms (wheezing, dyspnea), though lung function did not differ significantly between smokers and non-smokers.
Conclusions:
- Young adults with alpha(1)-antitrypsin deficiency (PiZ phenotype) exhibit normal lung function but a high prevalence of asthma symptoms.
- Smoking is linked to a greater frequency of respiratory symptoms in this population, highlighting the importance of smoking cessation.
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 (FEV(1)) was 98 (14)% predicted, vital capacity (VC) was 103 (14)% predicted, and the mean FEV(1)/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 FEV(1) (% predicted) was -1.2% (95% CI -2.1 to -0.3), in VC (% predicted) was -1.5% (95% CI -2.0 to -0.9), and in the FEV(1)/VC ratio (%) was -0.3% (95% CI -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.