Pulmonary Function and Respiratory Diseases in Different Genotypes of Alpha-1 Antitrypsin Deficiency

OBJECTIVE: Respiratory disease is the major cause of morbidity and mortality in patients with alpha-1 antitrypsin deficiency, mainly in homozygous PI*ZZ individuals. However, this association is uncertain in subjects with other deficiency genotypes. The objective of this study was to assess, in the context of alpha-1 antitrypsin deficiency, the existence of further risk factors that have been associated with respiratory diseases. MATERIAL AND METHODS: Lung function was assessed by spirometry in a sample of 1334 patients with a known genotype for the SERPINA1 gene whose serum alpha-1 antitrypsin levels had been previously determined. Patients with a normal genotype (PI*MM) were compared to 389 patients carrying a deficiency allele. RESULTS: Statistically significant associations were detected between (i) PI*ZZ genotype and abnormal FEV(1) values (χ(2) = 26.45; P < .0002), FEV(1)/FVC (χ(2) = 14.8; P < .02) or forced mid-expiratory flow 25%-75% (χ(2)=22.66; P < .0009); (ii) chronic obstructive pulmonary disease and PI*ZZ odds ratio: 26.5; 95% CI: (2.6-265.9); P < .005 and or PI*SS genotype odds ratio: 9; 95% CI: (2-40.1); P < .004; (iii) prevalence of COPD in PI*MZ subjects and smoking habit (P < .01), low body weight (P < .01) or older age (P < .0001). CONCLUSION: The PI*ZZ and PI*SS genotypes seem to be associated with the prevalence of chronic obstructive pulmonary disease. Tobacco use, low body weight, and older age are risk factors that increase the probability of prevalence of chronic obstructive pulmonary disease by up to 70% in PI*MZ individuals.