|ISSN No. 1606-7754 Vol.12 No.3 December 2004|
Does Body Mass Index associate with the endoscopic severity of gastroesophageal reflux disease?
Tamás G. Tóth, Pál Demeter, Róbert Sike, Ákos Pap
Szent János Hospital, Outpatient Clinic of Gastroenterology, Diósárok u. 1.,1125 Budapest, Hungary
To evaluate the association between body mass index (BMI) and gastroesophageal reflux disease (GERD) severity in the group of patients frequently suffering from moderate/severe gastroesophageal reflux symptoms, one hundred and fifty eight previously untreated patients underwent upper panendoscopy as indicated by typical moderate/severe reflux symptoms, occurring three or more times per week. Patients’ BMI values were tabulated and compared to the severity of endoscopic findings (according to Savary-Miller/modified by Siewert). Association between reflux disease activity and BMI was analyzed by Kruskall-Wallis test, while mild and severe group were compared using Mann Whitney test. Analyzing the whole group, including the patients who had no endoscopically verified erosions (Savary-Miller 0 stage = non erosive reflux disease/NERD) association was found at the level of perceivable statistical significance (p=0.0501). However subdividing the examined population into mild (Savary-Miller 0-1 stage) and severe (Savary-Miller 2-4 stage) groups according to the endoscopically verified mucosal lesions of the esophagus, there was a strong significant relationship between severity of GERD and BMI (p=0.0056). In the group of patients with moderate and severe GERD symptoms elevation of BMI can be a risk factor of increased severity of GERD particularly in those who already have erosive mucosal lesions at the time of examination.
Key words: body mass index, gastroesophageal reflux disease, severity, association
Prevalence of GERD and obesity are both increasing in industrialized countries.1 GERD is the manifestation of gastric acid exposure of the esophagus. Heartburn (a retrosternal burning sensation), acid regurgitation (a sour taste in the mouth) and dysphagia are considered typical and specific symptoms of GERD.2 The relationship between overweight (BMI 25 kg/m2 or obesity (BMI 30 kg/ m2 and GERD is still controversial.
A German study (based upon a nationwide information campaign) of 1,296 patients with reflux episodes daily and several times a week3 showed that BMI had no impact on the frequency of reflux symptoms. Similarly, a Swedish survey4 based on 820 face-to-face interviews found no association between BMI at 20 years of age, BMI 20 years before the interview or maximum adult BMI and severity or duration of reflux symptoms.
On the other hand a strong correlation was found between BMI and severity of GERD, defined and quantified by DeMeester (pH-metric) score.5 In the Bristol Helicobacter Project the relationship between BMI and severity of GERD reached conventional statistical significance.6 In a 2003 Swedish study of 3113 patients who reported on severe heartburn or regurgitation, a dose-response association was detected between BMI and reflux in both sexes with even stronger significance among women especially premenopausally.7
Increased intra-abdominal pressure impairs the „second sphincter” function of crural diaphragm, which determines anatomical and functional impairments. Such displacement of the lower esophageal sphincter leads to increased esophageal acid exposure, subnormal lower esophageal sphincter (LES) pressure8 and reflux symptoms. There are evidences that obese subjects have elevated gastro-esophageal pressure gradient from the mechanical burden of excessive fat with significantly prolonged esophageal transit time.9 Obese persons with higher prevalence of hiatal hernia are also more sensitive to the presence of acid in the esophagus. Obesity seems to be a strong risk factor for gastroesophageal reflux10 with high prevalence of asymptomatic esophageal motility disorders (in morbidly obese) suggesting abnormal visceral sensation.11 Furthermore, obesity associated vagal abnormalities promote higher output of bile and pancreatic enzymes, which makes the refluxate more toxic and irritating to the esophageal mucosa than in lean patients.12
In addition to the many comorbidities of obesity, there are evidences that intestinal and extraintestinal symptoms (like abdominal pain, reflux, irritable bowel, sleeping disturbances, obstructive sleep apnea) are more common and more intense in this population.13,14
Previously most studies examined the correlation between the degree of obesity and the existence/frequency of GERD symptoms using surveys, esophageal sphincter manometry or 24 h pH monitoring.
In our study we analyzed the association between BMI and the severity of endoscopically verified mucosal lesions in patients with moderate/ severe GERD symptoms. This is thought to be essential since we know that obesity and GERD are both increasingly common conditions, overweight increases the risk of GERD hospitalization,15 BMI and the presence of oesophagitis at initial examination independently predict long-term acid suppression therapy,16 and GERD symptom severity is associated with impaired health-related quality of life.17
In addition we must not forget about the possible development of Barrett’s esophagus, the strongest independent risk factor of esophageal adenocarcinoma together with obesity.18