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Obesity, Abdominal Diameter, and GERD
At least in white patients, the amount of visceral adipose tissue is related to the severity of GERD symptoms.
Much evidence exists to support an association between obesity and gastroesophageal reflux disease (GERD; e.g., Journal Watch Gastroenterology Jun 13 2006). The pathophysiology of this association is an increase in the intragastric pressure as well as increased spatial separation between the esophagogastric junction component attributed to the lower esophageal sphincter and that attributed to the crural diaphragm (Journal Watch Gastroenterology Apr 25 2006) in overweight people. To date, research on this association has focused on correlation of GERD with body-mass index (BMI), defined as overweight (BMI, 25–25.9 kg/m2) or obese (BMI, 
30); however, waist circumference or abdominal diameter might be a better indicator.
The first study was a cross-sectional analysis of 206 consecutive patients from a single center in Texas who underwent 24-hour pH monitoring. Height, weight, and waist and hip circumferences were recorded. Obesity was associated with a significant increase in the number and duration of reflux episodes, especially in the postprandial period. The association between obesity and all measures of esophageal acid exposure was attenuated when adjustment was made for waist circumference.
The second study was a cross-sectional analysis of GERD symptoms within a cohort of more than 80,000 members of a large healthcare cohort in California. Members who presented for routine health evaluations were asked to complete detailed standardized and validated health questionnaires, which included some GERD-specific questions. Standard anthropometric measurements were recorded. Symptoms of GERD were evident in 11% of the cohort. GERD symptoms were associated significantly with high BMI alone for both white men and white women, although this correlation was considerably attenuated by adjustment for abdominal diameter. Abdominal diameter (adjusted for BMI) was associated with GERD symptoms (odds ratio, 1.9; 95% CI, 1.6–2.2) for white patients, whereas no consistent association was seen for black or Asian patients.
Comment: These two studies provide new data that emphasize the importance of abdominal girth as the key factor in GERD-related symptoms that are associated with overweight and obese BMIs. Abdominal diameter is associated strongly with visceral adipose tissue, which is related to more-severe GERD complications such as Barrett esophagus (Am J Gastroenterol 2005; 100:2151). Visceral adipose tissue and subcutaneous adipose tissue differ in metabolic activity, and this difference could influence GERD through alterations of motility, cytokines, and other inflammatory mediators. That BMI and GERD symptoms are not correlated in some populations might be due to racial variations in development of visceral versus subcutaneous adipose tissue. Subsequent studies on weight and GERD will need to focus specifically on abdominal diameter and the possible superimposed variable effect of race.
Published in Journal Watch Gastroenterology August 10, 2007
Citation(s):
El-Serag HB et al. Obesity increases oesophageal acid exposure. Gut 2007 Jun; 56:749-55.
- Original article (Subscription may be required)
- Medline abstract (Free)
Corley DA et al. Abdominal obesity, ethnicity and gastro-oesophageal reflux symptoms. Gut 2007 Jun; 56:756-62.
- Original article (Subscription may be required)
- Medline abstract (Free)