Impact Of Age on pH, 8-Isoprostane, and Nitrogen Oxides in Exhaled Breath Condensate

Background: Few studies have addressed the effects of aging on levels of inflammatory markers in exhaled breath condensate (EBC). The aim of this study was to determine whether there are significant age-associated differences in pH, 8-isoprostane, and nitrogen oxide values in EBC from a population of healthy adults. Material and methods: EBC samples were obtained from 75 healthy volunteers aged 18 to 80 years and stratified into five groups according to age (n = 15): IS to 29, 30 to 39 years, 40 to 49 years, 50 to 59 years, and 60 to 80 years. The following were measured in the samples collected: pH before and after deaeration, nitrite, nitrate, and 8-isoprostane. Differences between the groups were assessed by the Kruskal-Wallis test. Results: Significant differences in deaerated pH (p < 0.0001) were found in the group of individuals 60 to 80 years of age as compared to the remaining groups. Significant differences were also found in 8-isoprostane levels between the younger and older groups (18 to 29 years and 30 to 39 years of age; p = 0.006 and p = 0.034, respectively). There were no significant differences in nitrite or nitrate values between younger and older individuals. Conclusion: The results of this study indicate that pH and 8-isoprostane levels in EBC show a relationship with age. Thus, values obtained in studies with control groups may require adjustment for these factors. (CHEST 2009; 135:462-467)