Rationale: All Swedish newborn infants were screened for α1-antitrypsin (AAT) deficiency between 1972 and 1974. The cohort of 127 individuals with severe AAT deficiency (PiZZ) and 54 with moderate AAT deficiency (PiSZ) has been followed up regularly.
Objectives: To compare smoking habits, quality of life, respiratory symptoms, and lung and liver function at the age of 34 years in this cohort and among 300 age-matched control subjects randomly selected from the Swedish population registry.
Methods: The study participants answered a questionnaire on smoking habits and symptoms; underwent spirometry, including FEV1 and FVC; and provided blood samples. Health-related quality of life was assessed by using the St. George's Respiratory Questionnaire (SGRQ).
Measurements and main results: One hundred sixteen PiZZ, 48 PiSZ, and 229 control subjects (normal AAT level [PiMM]) answered the questionnaire. Eighty-eight PiZZ (76%), 36 PiSZ (75%), and 144 PiMM (63%) subjects had never smoked (P = 0.02). No significant differences were found in lung function parameters between the protease inhibitor (Pi) subgroups, nor were any discovered between the smoking subgroups. In all Pi subgroups, the symptom score on the SGRQ was significantly lower in ever-smokers than in never-smokers (P = 0.01 for PiZZ, P = 0.009 for PiSZ, and P = 0.01 for PiMM). The mean plasma levels of liver enzymes and albumin were within normal range in all Pi subgroups. However, the mean γ-glutamyl transpeptidase and albumin levels were significantly higher in the PiZZ than in the PiMM subjects (P < 0.05).
Conclusions: In this population-based study, no differences in lung function or symptoms were found between subjects with AAT deficiency and control subjects, but smoking frequency was significantly lower among the subjects with AAT deficiency than in the controls at age 34 years.
Keywords: lung function; neonatal screening; respiratory symptoms; smoking; α1-antitrypsin deficiency.