Obesity has been associated with gastro-esophageal reflux disease (GERD); however, the mechanism by which obesity may cause GERD is unclear.
Dr Hashem B El-Serag and colleagues from the USA examined the association between esophageal acid exposure and total body or abdominal anthropometric measures.
A cross-sectional study of consecutive patients undergoing 24 h pH-metry was conducted.
| A BMI of >30 kg/m2 was associated with a significant increase in acid reflux episodes |
| Gut |
Standardised measurements of body weight and height as well as waist and hip circumference were obtained.
The association between several parameters of esophageal acid exposures and anthropometric measures were examined in univariate and multivariate analyses.
206 patients (63% women) with a mean age of 51.4 years who were not on acid-suppressing drugs were enrolled.
A body mass index (BMI) of >30 kg/m2 (compared with BMI<25 kg/m2) was associated with a significant increase in acid reflux episodes, long reflux episodes (>5 min), time with pH<4, and a calculated summary score.
These significant associations have affected total, postprandial, upright and supine pH measurements.
Waist circumference was also associated with esophageal acid exposure, but was not as significant or consistent as BMI.
When adjusted for waist circumference by including it in the same model, the association between BMI>30 kg/m2 and measures of esophageal acid exposure became attenuated for all, and not significant for some, thus indicating that waist circumference may mediate a large part of the effect of obesity on esophageal acid exposure.
Dr El-Serag concluded that, "Obesity increases the risk of GERD, at least partly, by increasing esophageal acid exposure. Waist circumference partly explains the association between obesity and esophageal acid exposure".