Effect of smoking on the results of esophageal pH measurement in clinical routine.

Because data on the effects of smoking on gastroesophageal reflux are controversial, we evaluated the effect of smoking on the results of esophageal 24-hour pH-metry in clinical routine. Participants were 280 consecutive patients with symptoms suggestive of reflux disease, 78 smokers, and 202 nonsmokers. Of the smokers, 45 actually smoked during the pH measurement and 33 abstained from smoking. The frequency of reflux episodes, the fraction of time pH was < 4, and the percentage of abnormal 24-hour pH-metry results were compared among actual smokers, abstaining smokers, and nonsmokers. In actual smokers, the effect of smoking on gastroesophageal reflux was further analyzed by comparing the reflux frequency and the fraction of time that pH was < 4 for a 10-minute period before, during, and after smoking. We found no difference in reflux frequency and fraction of time that pH was < 4 among actual smokers, abstaining smokers, and nonsmokers, regardless of a normal or an abnormal pH-metry result. The percentage of patients with a pH-metry result indicating disease was similar in the three groups, at 53%, 52%, and 50%, respectively. Gastroesophageal reflux was not increased during smoking a cigarette or in the postsmoking period compared with the presmoking period. Neither being a smoker nor actually smoking a cigarette had a negative influence on gastroesophageal reflux. Thus smoking or abstaining from smoking does not modify the results of pH-metry in clinical routine.