Deletion allele of the angiotensin-converting enzyme gene as a risk factor for pneumonia in elderly patients

Purpose Aspiration due to an age-related reduction in cough is a major cause of pneumonia in elderly persons. Because the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene (ACE) has been associated with the cough reflex, we studied whether this genetic polymorphism was also associated with the risk of pneumonia. Subjects and methods We studied 1011 elderly inpatients (221 men and 790 women, mean [± SD] age of 82 ± 7 years) in a long-term care hospital. The association between the ACE I/D polymorphism and the incidence of pneumonia (defined using specific criteria that included radiographic abnormalities) was assessed during an 8-month period that excluded the winter. Data were analyzed using proportional hazards models, with adjustment for age, sex, and other potential confounders. Results During follow-up, 87 cases (9%) of pneumonia occurred, 38 of which were fatal. The ACE DD allele (vs. ID + II) was associated with an increased risk of pneumonia (relative risk [RR] = 2.9; 95% confidence interval [CI]: 1.7 to 4.8, P< 0.001) and fatal pneumonia [RR = 4.4; 95% CI: 2.1 to 9.0; P< 0.0001). Conclusion The ACE D allele is an independent risk factor for pneumonia in elderly persons.