Abstract: Aim: To study the relationship in obesity，esophageal motor functional disorder and esophageal reflux. Methods: Patients (n = 146) were categorized in GERD and controls after clinical assessment, esophageal manometry, and pH monitoring. Non-obese (BMI≤27.9 kg/m2) and obese (BMI ≥ 28 kg/m2) were compared in laboratory of esophageal physiology. Results: Obese showed higher LESP in GERD patients (16.4±4.7vs. 14.4±3.2 mmHg, P=0.014), higher distal esophageal amplitude in both controls (107±48 vs. 77±20 mmHg, P=0.04) and GERD patients (98±44 vs. 79±39 mmHg, P=0.017) , higher frequency of nutcracker esophagus in controls (25 vs. 0%, p =0.031), lower frequency of ineffective motility in GERD patients (7 vs. 20%, p = 0.035), and higher esophageal acid exposure in both controls [total time percentages of pH＜4: 3.0% (0.9~5.6) vs. 1.3% (0.3~2.7),P=0.003] and GERD patients [upright: 13.2% (5.1~19.2) vs. 10.4% (2.9~18.1),P=0.001]. BMI was positively correlated with time percentages of pH＜4 (p＜0.001), distal esophageal amplitude (p = 0.007),or LESP (p = 0.006). Conclusions: Obese patients differed from non-obese in many aspects when evaluated in laboratory of esophageal physiology. Obese patients showed stronger peristalsis and increased acid exposure in the esophagus.

Key words: Body mass index, Esophageal motility disorders, Gastroesophageal reflux disease, Obesity