Worldwide Epidemiology of Gastroesophageal Disease Serhat Bor, MD Ege University School of Medicine, Sect Gastroenterology & Ege Reflux Group Izmir, Turkey Gastroesophageal reflux disease (GERD) is one of the most common chronic diseases in adults. It affects not only the esophagus but also the upper airways and it is associated with a wide range of extra-esophageal symptoms. Therefore, treating GERD requires collaboration among many different disciplines, including Gastroenterology, ENT, Pulmonary Medicine, General Surgery, Pediatrics, Internal Medicine and General Practice. Approximately 4650 publications can be found in PubMed by using the terms “GERD” and “prevalence” as keywords. However, it is difficult to compare the epidemiologic studies for several reasons; 1) Studies have been performed using at least 10 different questionnaires, including the Mayo GERD Questionnaire, GERD-Q, DIGEST-Q and RDQ; 2) Various definitions and criteria for GERD have been used in both different and the same questionnaires, but the most common definition is heartburn and/or acid regurgitation once a week or more frequently; 3) Some studies have used non-validated questionnaires; 4) The randomization methodology and response rates differ across studies; and 5) The word “reflux” does not exist in some languages. Gastroesophageal reflux symptom prevalence High-quality prevalence studies from Western countries have been undertaken since the 1990s and similar studies were only performed in the 2000s in eastern countries. Because one of the most common questionnaires is the Mayo GERD Questionnaire, the prevalence studies that used this questionnaire and implemented the same diagnostic criteria are summarized in Table 1. If all of the published studies are considered, the worldwide prevalence of GERD is approximately 15-25%. Although there are major discrepancies between Western and Eastern countries, it is not clear exactly where to divide the world. Western European countries, the USA, and Canada can be pooled in the same group because they share similar cultural and social characteristics. Additionally, these countries have low Helicobacter pylori rates and better health care facilities. The highest numbers are observed in the USA (26.2%), Norway (26%) and Sweden (25.9). Different rates have been reported within these countries, but the differences were not significant. An interesting finding from the USA concerned different ethnic groups: the prevalence rates were 38% in Hispanics, 14.7% in Asians, 29.9% in Caucasians and 22.1% in African-Americans. In a pivotal study, Locke et al administered the Mayo questionnaire to 1511 subjects in Olmsted County by mail. They found that the subjects experienced the following symptoms at least once weekly: heartburn (17.8%), regurgitation (6.3%) and either symptom (19.8%). If all of the studies from Western countries were evaluated cumulatively, the prevalence of heartburn was 23%, and that of acid regurgitation was 16%. The majority of studies from Eastern countries originate from South-East and East Asian populations; the prevalence of GERD (common heartburn and/or acid regurgitation that is experienced once a week) in these populations is 2.5–8.2%, which is markedly lower than that reported in the Western studies. One of the first large-scale randomized studies in China that used the Mayo questionnaire via phone interview found a very low prevalence of GERD (2.5%). Subsequent studies showed a meaningful increase of this rate to 6.2%. Japan is the only exception among the Far East countries: a study performed using QUEST showed a high GERD prevalence of 16.5%, one of the highest figures among the Far East countries. Other Eastern countries have added more data through studies, particularly within the last 5 years. Iran, for example, presents different profiles, and the prevalence rates range from 2.7% to 33%. One recent study performed using the Mayo Questionnaire in Eastern Iran showed a prevalence rate of 25.7% for GERD and regurgitation and noted that regurgitation was more common than heartburn (the heartburn rate was not reported). Two studies from India, which addressed subjects who were admitted to the hospital, reported similar values: 5.3% and 7.1%. Very limited data exist from the southern and eastern parts of the Mediterranean. One study, in Tunisia, defined GERD as occurring once a year or more frequently; therefore, the prevalence rate reached 24.8%. Another study, conducted in Israel via telephone surveys, reported lower figures: 12.5% of the respondents reported weekly or more frequent symptoms. Compared with prevalence, there are far fewer studies regarding the incidence of GERD. However, it has been shown that the incidence of the disease is on the rise. Symptom profile According to epidemiologic studies, one of the major differences between Western and Eastern countries is the prevalence of typical symptoms of GERD. Western countries primarily report heartburn, whereas nearly all other countries predominantly report acid regurgitation. Only a minority of countries (such as Russia and Argentina) have similar rates for both symptoms (Table 1). These differences are likely underestimated but important because acid regurgitation represents a different therapeutic profile than heartburn. The modality of these differences is not clear but may be due to less overall medicine consumption, decreased obesity, genetic factors (low acid output), dietary factors (such as low consumption of hot or carbonated drinks), low fat meals, and decreased alcohol and tobacco product consumption. Most World Digestive Health Day WDHD May 29, 2015 WGO HANDBOOK HEARTBURN: A GLOBAL PERSPECTIVE 12
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