Relation Between Metabolic Syndrome and Gastroesophageal Reflux Disease

Metabolic syndrome (MetS), characterized by central obesity, insulin resistance, hypertension, and dyslipidemia, has increasingly been associated with gastrointestinal diseases, particularly gastroesophageal reflux disease (GERD). GERD is a chronic and often progressive condition where stomach contents reflux into the esophagus, resulting in symptoms such as heartburn and regurgitation. The association between these two conditions is of growing interest due to overlapping pathophysiological mechanisms involving visceral fat, low-grade inflammation, and changes in gastrointestinal motility.

The metabolic dysfunction that characterizes fatty liver disease also contributes to reflux symptoms. Patients with metabolic-associated fatty liver disease (MAFLD) have demonstrated a higher prevalence of GERD symptoms. This relationship is thought to be driven by hepatic insulin resistance, increased abdominal adiposity, and systemic inflammation-all of which promote esophageal dysfunction and impaired gastric emptying .

Insulin resistance, a core feature of MetS, has been independently linked to GERD severity. The triglyceride-glucose (TyG) index, a widely accepted surrogate marker of insulin resistance, has been positively associated with both GERD and erosive reflux disease (ERD). This suggests that glucose and lipid metabolism disturbances may impact esophageal barrier function, possibly by altering smooth muscle performance or increasing oxidative stress in esophageal tissues.

Genetic and lifestyle factors contributing to metabolic dysfunction also appear to play a causal role in the development of GERD. Higher genetically predicted body mass index (BMI), waist circumference, and type 2 diabetes risk have been associated with increased GERD incidence. Lifestyle factors such as physical inactivity and high-fat diets not only exacerbate metabolic abnormalities but also increase the risk of reflux, pointing to a multifactorial relationship.

Central obesity, a major criterion of MetS, has been independently associated with GERD and erosive esophagitis. The mechanism may involve elevated intra-abdominal pressure, which impairs LES competence, and elevated levels of pro-inflammatory adipokines. These changes facilitate mucosal damage and impair esophageal clearance, contributing to both symptomatic and silent GERD manifestations.