麻豆传媒

Obesity is an identified risk factor for non-erosive gastroesophageal reflux disease (GERD). Previous studies have examined the association of GERD with anthropometric indices, such as body mass index (BMI) and muscle mass. Building off of this, a research group based in Taiwan, where prevalence of GERD is reported to be around 25%, sought to examine correlations of several different obesity indices with GERD, including BMI, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body roundness index (BRI), abdominal volume index (AVI), lipid accumulation product (LAP), visceral adiposity index (VAI), and triglyceride-glucose (TyG) index.¹

The investigators used a large Taiwanese cohort of more than 120,000 participants derived from the Taiwan Biobank, which enrolls cancer-free individuals ages 30 to 70 years and includes lifestyle, genetic, and medical data.¹

Several obesity indices are linked to GERD

The research team used multivariable logistic regression analysis to examine the associations of obesity indices with GERD.¹ Covariates in the multivariable model included age, sex, diabetes mellitus and hypertension, smoking and alcohol history, a habit of regular exercise, fasting glucose, triglycerides, total and low-density lipoprotein cholesterol, estimated glomerular filtration rate, and uric acid. High values of the following (per 1%) were found to be associated with GERD:

• WHR (odds ratio [OR] 1.009, 95% confidence interval [CI] 1.006 to 1.012; P<.001)
• WHtR (OR 1.005, 95% CI 1.002 to 1.008; P=.003)
• BRI (OR 1.022, 95% CI 1.007 to 1.038; P=.005)
• AVI (OR 1.013, 95% CI 1.008 to 1.019; P<.001)

Additionally, measurements that take into account triglycerides, fasting blood glucose levels, and high-density lipoprotein cholesterol were also significantly associated with GERD (per 1%):

• LAP (OR 1.001, 95% CI 1.001 to 1.002; P<.001)
• VAI (OR 1.013, 95% CI 1.005 to 1.022; P=.002)
• TyG index (OR 1.068, 95% CI 1.036 to 1.102; P<.001)

The problem with BMI

While the authors noted that previous studies have identified BMI as being strongly associated with GERD, their own study showed no such association (P=.384). It鈥檚 widely recognized that BMI does not accurately reflect body fat distribution, and individuals with normal BMI may still have central obesity.

In the current study, measurements that include waist circumference鈥擶HR, WHtR, BRI, AVI, LAP, and VAI鈥攚ere all shown to be associated with GERD, leading the authors to hypothesize that central obesity, an indicator of excess body fat accumulation specifically related to the abdomen, may be a more important causative factor for GERD than general obesity as defined by BMI. 

This is in line with a meta-analysis that showed that Barrett鈥檚 esophagus, esophageal inflammation, and esophageal adenocarcinoma were all associated with central adiposity, but independent of BMI.² The authors of the current study noted, however, that diet and lifestyle habits, such as high dietary fat intake, fast food, and irregular meals, have been linked to both GERD and obesity, making the possibility of a bidirectional association between GERD and obesity difficult to clarify.

Putting the findings in perspective

Because the study population included a higher percentage of female than male participants with GERD (64% versus 36%), there鈥檚 the potential for some bias in the study. To try to combat this, the researchers used the propensity score matching method, a 1:4 Greedy nearest neighbor matching algorithm with a caliper of 0.25, to create a matched cohort using these scores.

Using this method, the researchers again found that, with the exception of BMI, high obesity index values were significantly associated with GERD. Because this was a cross-sectional study, however, the authors say they weren鈥檛 able to evaluate how long the patients had GERD and therefore couldn鈥檛 examine any causal relationships between the obesity indices and GERD.

Additionally, GERD was self-reported on questionnaires and not verified or measured for severity, but a previous study from Taiwan had reported fair consistency between self-reported disease and claims records.³ Lastly, the current study may be limited by its lack of information related to other possible causes of GERD, such as hiatal hernia or use of nonsteroidal anti-inflammatory drugs.

Nonetheless, the authors reported that high levels of multiple obesity indices (WHR, WHtR, BRI, AVI, LAP, VAI, and TyG index), but not BMI, were associated with GERD, with the GERD-TyG connection being a novel finding not previously described in the literature. The authors therefore concluded that their findings 鈥渕ay suggest that different obesity indices are associated with different gastrointestinal disorders.鈥�¹

Published: December 27, 2024