Acute effects of smoking and food consumption on breath condensate pH in healthy adults.

Acute effects of food and cigarette consumption on exhaled breath condensate (EBC) acidity are insufficiently explored. The study aimed to evaluate potential changes in EBC pH within 2 hours following cigarette or food consumption. In 15 healthy smokers, samples were obtained after 10 hours of abstinence from smoking and then 15, 30, 60, and 120 minutes after smoking 1 cigarette. In 19 healthy nonsmoking adults, EBC samples were obtained in the morning after an overnight fast, and then 30, 60, and 120 minutes following standardized breakfast. Smoking of 1 cigarette after overnight tobacco abstinence induced significant increase in EBC pH during the 2-hour observation period, for approximately 0.60 logarithmic units (repeated-measures analysis of variance [ANOVA], P < .0001). The average presmoking pH value in smokers (7.00 ± 0.50) was significantly lower than average value in nonsmokers (7.62 ± 0.31; P = .0001). No effect of food consumption was found. These results show that cigarette smoking acutely increases EBC pH in healthy smokers. Smoking status and abstinence from smoking before EBC sampling seems to be important in studies evaluating EBC pH and should be standardized or at least stated in the methodology. Acute effects of food were not found under described study conditions in healthy adults.