In males but not females, hyperinsulinemia, insulin resistance, and metabolic syndrome are independently associated with a higher risk of Barrett’s esophagus (BE), based on a recent case-control study.

These findings offer some insight into why men have higher rates of BE and esophageal adenocarcinoma than do women, reported lead author Bradley J. Kendall, MBBS, PhD, of the University of Queensland in Brisbane, Australia, and colleagues.

“Esophageal adenocarcinoma (EA) and its precursor lesion, Barrett’s esophagus (BE), are more common in males than females,” the investigators wrote in the Journal of Clinical Gastroenterology. “In contrast, gastroesophageal reflux (GER), the major risk factor for BE and EA occurs at similar frequencies in both sexes. In addition, 10% to 20% of BE and EA cases report no history of GER symptoms. This suggests that non-GER factors are important in the development of BE and EA.”

To examine risk factors more closely, the investigators enrolled 227 patients with BE and 241 age- and sex-matched controls. Data were drawn from self-reported questionnaires, interviews, blood pressure readings, and anthropometric measurements, the latter of which included weight, height, and waist circumference. These patient characteristics were supplemented with fasted blood assays. The investigators looked for associations between BE and insulin level, Homeostatic Model Assessment of Insulin Resistance, metabolic syndrome, type 2 diabetes mellitus, insulin-like growth factors, and interleukin-6 (IL-6).

Across the entire population, independent associations were detected between BE and hyperinsulinemia (highest vs. lowest tertile; odds ratio, 1.9; P = .003), insulin resistance (OR, 1.9; P = .006) and metabolic syndrome (OR, 1.8; P = .004). For those with metabolic syndrome, risk of BE increased by 20% for each additional syndrome criterion (P = .02).

When stratifying by sex, however, all of the above risk factors remained statistically significant in men, but not in women. For male patients, compared with the population as a whole, risks were relatively higher for all three factors: hyperinsulinemia (OR, 2.1; P = .007), insulin resistance (OR, 2.1; P = .01), and metabolic syndrome (OR, 2.3; P = .001). Similarly, for men with metabolic syndrome, each additional syndrome criterion increased risk of BE by 40% (P = .005).

Regardless of sex stratification, the other evaluated characteristics (type 2 diabetes mellitus, insulin-like growth factors, and IL-6) were not associated with BE risk.

The investigators offered some possible mechanistic explanations for their findings.

“Hyperinsulinemia ... can result in increased insulin signaling, increased cellular proliferation, reduced apoptosis, oncogenic pathway activation, and enhanced cellular invasion,” they wrote. “In addition, abdominal obesity, which is the driver of these disorders of insulin homeostasis, also alters adipocytokine profiles and induces a chronic systemic inflammatory state. The inflammatory state can result in oncoprotein activation, angiogenesis, cellular proliferation, apoptosis, and metastasis.”

Concerning the difference between sexes, the investigators pointed to patterns of abdominal obesity. “[A]bdominal obesity and the associated metabolic sequelae are more common in males than females,” they wrote. “These observations give rise to the notion that the metabolic syndrome potentiates the inflammatory effects of the gastric refluxate in the distal esophagus and this may play a role in the male predominance of BE and EA.”

While these findings offer insight into the underlying processes that precipitate BE, the investigators suggested that more research is needed.

“The interactions of obesity hormones, GER, and the cells of the esophageal mucosa warrant further investigation,” they concluded.

The study was funded by the Queensland Cancer Fund, Queensland Government Smart State Fund, and the Princess Alexandra Hospital Research Foundation, and others. The investigators reported no disclosures.

SOURCE: Kendall BJ et al. J Clin Gastroenterol. 2019 Dec 24. doi: 10.1097/MCG.0000000000001307.