Fluctuating Risk Factors and Epidemiology

2.1 Introduction

The first description of Barrett’s esophagus (BE) is attributed to Sir Norman Barrett in 1950 who reported ulcerations in the tubular segment of stomach that had been tethered within the chest by a congenitally short esophagus . By the 1970s, it had been accepted that BE is an acquired condition associated with severe gastroesophageal reflux disease (GERD) and has a malignant predisposition . The definition has evolved over the past several decades and the currently accepted definition is that of a condition in which any extent of metaplastic columnar epithelium that predisposes to cancer development and replaces the stratified squamous epithelium that normally lines the distal esophagus. In the United States, presence of specialized intestinal metaplasia is a prerequisite for diagnosis, whereas in United Kingdom and rest of Europe, gastric metaplasia alone is enough to make a diagnosis of BE.

2.2 Prevalence

The true prevalence of BE is difficult to estimate because most of the patients with BE are asymptomatic and the diagnosis of BE requires endoscopic evaluation and histologic confirmation. The available prevalence rates vary widely between 0.4% and over 25% based on the age, gender, ethnicity, and symptoms in the populations studied. Variation of BE prevalence among asymptomatic general population should be carefully interpreted based on age, sex, and prevalence of GERD symptoms.

2.2.1 Population-Based Studies/Routine Endoscopy

In population-based studies, the overall prevalence of BE in general population varied between 1.6% and 6.8% in western countries . In a study by Gerson et al. , a 25% BE prevalence rate was noted in male veterans older than 50 years of age. In another study, both men and women above age 65 years undergoing screening colonoscopy were requested to undergo routine upper endoscopies after completing a detailed GERD questionnaire. Overall prevalence of BE was 16.7% and symptoms of heart burn were not significantly associated with BE .

2.2.2 Patients with Chronic Gastroesophageal Reflux Disease

Prevalence rates of BE in patients with symptomatic GERD are somewhat higher than in the general population with rates of 13–20% . Long segment BE is found in 3–5% and short segment BE in 10–15% .

2.2.3 Autopsy Studies

Many individuals with BE remain undiagnosed. In one of the few autopsy-based studies, Cameron et al. found a prevalence rate of 376 cases per 100,000 in Olmsted County, Minnesota, which was 21-fold higher than the clinically recognized cases in the county.

2.2.4 Geographic Variation

There is considerably more data on the prevalence of BE in western countries as compared to Asian countries. In general, the prevalence rates were higher in the western hemisphere compared to Asia. Two large prospective studies investigated the prevalence of BE in Japan and found an overall prevalence of BE of 0.9–1.2% . The prevalence rate of BE in China from a pooled analysis of reports from 1989 to 2007 was 2.4% . In South America, the prevalence rate of BE was 3.57% among patients with GERD symptoms .

2.3 Incidence

Due to the rapidly increasing incidence of esophageal adenocarcinoma (EAC) in United States , there has been concern for rising incidence of BE, a precursor for EAC. Between 1980 and 1996, a steady increase in the incidence of BE at 0.08% per year has been reported with a median incidence of 1.17% . It is not clear if this is a true increase or if it is due to increased recognition of BE from electronic health records and raising endoscopic volume. One of the largest studies from Northern California showed an increase in the incidence of BE from 14.5 to 22.9 per 100,000 person years between 1994 and 2007, even after adjusting for increase in endoscopy volume and age ( p <0.01), . Similar increases in incidence have been reported in Europe as well .

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