BACKGROUND Individuals with severe alpha-1-antitrypsin (AAT) deficiency have a well-known risk of developing emphysema but it is not known at which age the first symptoms occur and lung function declines. The aim of this study was to examine the prevalence of smoking, respiratory symptoms and lung function at the age of 30 in AAT-deficient individuals (PiZ and PiSZ) identified by neonatal screening. METHODS One hundred and seven PiZ, 45 PiSZ and 197 control subjects (PiMM) filled in a questionnaire regarding smoking habits and symptoms. Ninety PiZ, 40 PiSZ and 84 control subjects underwent spirometry including FEV(1) and FVC. RESULTS Twenty-one percent of PiZ, 23% of PiSZ and 34% of PiMM subjects had smoked at some time (p<0.05). Sixty-five percent of PiZ, 55% of PiSZ and 35% of PiMM ever-smokers reported shortness of breath on exertion (p<0.05 PiZ vs PiMM). The mean FEV(1) was 101% predicted (95% CI 98-104) in PiZ, 101% predicted (95% CI 97-106) in PiSZ, and 96% predicted (95% 93-98) in PiMM individuals (p<0.05). There was no difference in mean FEV(1) when comparing ever- and neversmokers in the different Pi groups separately. CONCLUSIONS At the age of 30, the AAT-deficient individuals in this cohort report more symptoms than the control subjects. Smoking is less common in the cohort compared to controls. Their lung function is normal.