Risk factors associated with the detection of pulmonary emphysema in older asymptomatic respiratory subjects

BACKGROUND: Several lung structural and functional abnormalities may occur associated with aging, including emphysema. In this study, we evaluated the frequency and risk factors associated with emphysema in respiratory asymptomatic individuals enrolled in our Lung Aging Program. From a cohort of 687 subjects, we found by high-resolution computed tomography (HRCT) 29 individuals (4%) with emphysematous changes that were compared with 87 controls (3:1) randomly selected from the same cohort. METHODS: This was a transversal, observational, case-control study where we examined demographics and functional characteristics, as well as telomere length and serum Klotho concentration, two conditions that have been associated with aging and some aging-associated diseases including emphysema. RESULTS: Individuals with subclinical pulmonary emphysema were older (72 ± 9 versus 67 ± 6 years), and primarily smoker males with low body mass index. Despite that they were asymptomatic, two of them exhibited a decrease of forced expiratory volume in 1 s (FEV(1)), with a lower FEV(1)/FVC suggesting airway obstruction. Cigarette smoking (OR = 5.43, CI95% 1.8–16.7), family history of lung disease (OR = 4.32, CI95% 1.0–19.0) and lower body mass index (OR 7.22, CI95% 1.2–3.5) were risk factors for the development of lung emphysematous changes. No association was found with telomere length and Klotho serum concentration. CONCLUSION: Our findings reveal that a small but important percentage of older people without respiratory symptoms, present pulmonary emphysema and indicate that smoking exposure and genetic background may contribute to etiological factors.