Wu JC et al. (2007) Obesity is associated with increased transient lower esophageal sphincter relaxation. Gastroenterology 132: 883–889

Mechanical stress imposed on the gastroesophageal junction might explain the high prevalence of GERD among the obese population. Transient lower esophageal sphincter relaxation (TLESR) is the most important mechanism associated with GERD, and might be the only one present in patients with mild reflux disease. Wu and colleagues, therefore, investigated the relationship between obesity and TLESR in patients without GERD.

In this prospective study, the authors consecutively enrolled three groups of patients matched for age and sex: 28 obese (BMI >30 kg/m2) individuals, 28 overweight (BMI 25–30 kg/m2) and 28 normal weight (BMI <25 kg/m2 and ≥20 kg/m2; controls). Patients did not have reflux esophagitis, hiatus hernia or a peptic ulcer. Patients had been referred for preoperative assessment of weight reduction procedures, had globus or noncardiac chest pain and had not responded to PPI therapy. All patients underwent preprandial and 2 h postprandial esophageal manometry and esophageal pH monitoring.

During the preprandial period all patients' gastroesophageal characteristics were similar. During the postprandial period the rate of TLESR and gastroesophageal gradients were raised among obese and overweight patients. Significantly greater proportions of the patients than controls had TLESR with acid reflux (63.5% and 51.8% vs 17.6%, P <0.001). The pH was lowered for longer in overweight and obese individuals than in normal weight individuals. BMI and waist circumference positively correlated with TLESR.

Although the reasons behind the increasing rate of TLESR with rising weight are unclear, the authors suggest that abnormal lower esophageal sphincter function is an early event in obesity-related GERD.