© FD-Communications Inc. Obesity Surgery, 14, 2004 1095 Obesity Surgery, 14, 1095-1102 Background: Controversial findings about the rela- tionships between obesity and gastro-esophageal reflux have been reported, as well as about the effects of weight loss and bariatric surgery on reflux. The aims of this study were to evaluate esophageal motil- ity and gastro-esophageal acid circadian patterns in obese patients and to test the effects of vertical banded gastroplasty (VBG) on these parameters. Methods: 14 obese subjects (BMI 36-53 kg/m 2 ), 4 men, 10 women, 27-61 years old, admitted for elective bariatric surgery, underwent clinical evaluation, upper endoscopy, esophageal manometry and gastro- esophageal pH monitoring. Evaluations were repeated 6 to 12 months after gastric surgery that consisted of a VBG (7 patients), accompanied in the other 7 patients with an anti-reflux procedure (fundo- plication). Manometric and pH-metric findings in the obese patients were compared with a normal-weight control group before and after the two different surgi- cal treatments. Results: Gastro-esophageal reflux was significantly more frequent in obese (57.1%) than in control group (7.1%). Esophageal motility in obese subjects was not different from controls. After VBG alone, we found a reduction in basal lower esophageal sphincter (LES) pressure and an increase of acid reflux. When VBG was accompanied by fundoplication, basal LES pres- sure increased and acid reflux frequency decreased. Conclusions: Obesity is associated with gastro- esophageal reflux. VBG reduced weight, but not gas- tro-esophageal acid reflux. Therefore, in our popula- tion, this operation cannot be considered as an antireflux procedure. Key words: Morbid obesity, bariatric surgery, gastroe- sophageal reflux Introduction Gastro-esophageal reflux disease (GERD) is a mul- tifactorial disease. Obesity has been reported as an independent risk factor for GERD by several mech- anisms. 1-8 Excess subcutaneous and intra-abdominal adipose tissue may cause reflux by increasing intra- gastric pressure and the abdominal-thoracic pres- sure gradient. 1,2,4 Increased gastric peptic secretion and abnormal gastric emptying have been described in obese subjects. 7,8 In addition, impaired esophageal motility may contribute to the genesis of GERD. 1 Controversial findings regarding the asso- ciation of GERD with obesity 9,10 and the effects of weight loss on reflux 11,12 have been reported in the literature. Gastric banding and vertical banded gastroplasty (VBG) are common gastric restrictive procedures for the treatment of morbid obesity. These opera- tions have been reported to cause GERD by some authors, 13,14 while others described beneficial or no effects on gastro-esophageal reflux. 15-17 The aims of this study were: 1) to evaluate, through gastro-esophageal pH recordings and esophageal manometry the frequency of gastro- esophageal acid reflux and esophageal motility Obesity and Gastro-esophageal Acid Reflux: Physiopathological Mechanisms and Role of Gastric Bariatric Surgery Vincenzo Di Francesco 1 ; Elda Baggio 2 ; Marina Mastromauro 2 ; Elena Zoico 1 ; Norma Stefenelli 2 ; Mauro Zamboni 1 ; Maria Panagiota Panourgia 1 ; Luca Frulloni 2 ; Paolo Bovo 2 ; Ottavio Bosello 1 ; Giorgio Cavallini 2 1 Department of Biomedical and Surgical Sciences and 2 Department of Surgery and Gastroenterology, University of Verona, Verona, Italy Reprint requests to: Dr.Vincenzo Di Francesco, MD, PhD, Dept. of Biomedical and Surgical Sciences, Clinica Geriatrica, Ospedale Maggiore, p.le Stefani 1, 37126, Verona, Italy. Fax: ++39 0458072043; e-mail: vincenzo.difrancesco@univr.it