J Neurogastroenterol Motil 2011; 17(1): 14-27  https://doi.org/10.5056/jnm.2011.17.1.14
Epidemiology of Gastroesophageal Reflux Disease in Asia: A Systematic Review
Hye-Kyung Jung*

Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Korea.

Correspondence to: Hye-Kyung Jung, MD. Department of Internal Medicine, Ewha Womans University Mokdong Hospital, 911-1 Mok-dong, Yangcheon-gu, Seoul 158-710, Korea. Tel: +82-2-2650-2874, Fax: +82-2-2655-2874, junghk@ewha.ac.kr
Received: November 21, 2010; Revised: December 14, 2010; Accepted: December 16, 2010; Published online: January 26, 2011
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Ethnic and geographical differences are important factors in studying disease frequencies, because they may highlight the environmental or genetic influences in the etiology. We retrieved the studies which have been published regarding the epidemiologic features of gastroesophageal reflux disease (GERD) in Asia, based on the definitions of GERD, study settings, publication years and geographical regions. From the population-based studies, the prevalence of symptom-based GERD in Eastern Asia was found to be 2.5%-4.8% before 2005 and 5.2%-8.5% from 2005 to 2010. In Southeast and Western Asia, it was 6.3%-18.3% after 2005, which was much higher than those in Eastern Asia. There were robust epidemiologic data of endoscopic reflux esophagitis in medical check-up participants. The prevalence of endoscopic reflux esophagitis in Eastern Asia increased from 3.4%-5.0% before 2000, to 4.3%-15.7% after 2005. Although there were only limited studies, the prevalence of extra-esophageal syndromes in Asia was higher in GERD group than in controls. The prevalence of Barrett’s esophagus was 0.06%-0.84% in the health check-up participants, whereas it was 0.31%-2.00% in the referral hospital settings. In summary, the prevalence of symptom-based GERD and endoscopic reflux esophagitis has increased in Asian countries. However, the prevalence of Barrett’s esophagus in Asia has not changed and also still rare.
Keywords: Asia, Epidemiology, Gastroesophageal reflux, Prevalence
Introduction

Gastroesophageal reflux disease (GERD) broadly includes the whole spectrum of reflux disease, from intermittent symptoms like heartburn or acid regurgitation to endoscopic reflux esophagitis and Barrett's esophagus.1 It usually gives a considerable impact on the quality of the patient's life not only by the symptoms, but also by the following consultation procedures and medical cares. While GERD is a common disease and also the major upper gastrointestinal problem in Western countries, its prevalence amongst Asian has been reported to be relatively low.2-4

During the recent decade, several studies about prevalence of symptom-based GERD and endoscopic reflux esophagitis have revealed generally higher number of patients compared to other previous Asian studies. Time trend studies have also shown the increase of prevalence both in symptom based-GERD and endoscopic reflux esophagitis.5

Heartburn and acid regurgitation are the characteristic symptoms of GERD. Heartburn is defined as a burning sensation at the retrosternal area. However, different criteria of GERD have been published from all over the world including Asia, with the frequency of its symptoms differing from once a week to even once a year. Furthermore, it also has been attributed to the lack of the exact word for heartburn in some Asian languages, such as Chinese or Korean.6 In addition, there has not been any consensus distinguishing GERD from dyspepsia.

In Asia, endoscopic reflux esophagitis is quite commonly diagnosed because the cost of endoscopic examination is relatively inexpensive. Actually, a lot of asymptomatic people get the upper endoscopic examinations for gastric cancer screening and comprehensive medical check-up. The major limitation of studies with individuals in screening program is that it might not represent the general population. However, such studies have advantages of their large sample size and consistent diagnostic manners.

This paper was aimed to review the epidemiologic aspect of GERD and its related disease manifestations, such as endoscopic reflux esophagitis, Barrett's esophagus and extra-esophageal syndrome, according to various definitions, study settings, publication years and geographical regions in Asia.

Methods

Identification and Eligibility Assessment of Relevant Studies

A systematic PubMed search was performed to identify all of the reports written about the prevalence of GERD, published from January 1995 to October 2010, using combinations of the following index terms: "gastroesophageal reflux disease," "reflux," "gastroesophageal reflux" or "esophagitis" and "prevalence" or "epidemiology." Only the papers published in English were reviewed. Included studies had to meet all of these 3 following criteria: (1) including epidemiologic studies performed with at least 200 subjects gathered by population-based or medical check-up settings; (2) having detailed description of GERD definition or its related manifestations and (3) subjecting any sample type, including subjects from tertiary hospitals, to collect data about extra-esophageal symptoms or Barrett's esophagus.

Data Extraction

Following information was abstracted from each study included: the year of publication, study periods, country of subjects, sample types (the population-based type, subjects who underwent the medical check-up or those from referral hospitals), study design (derived from case-control, cohort or other cross-sectional studies), sample size and prevalence of GERD, reflux esophagitis, Barrett's esophagus or extra-esophageal syndromes of GERD.

All studies were sub-grouped by each geographical region, based on Globocan 2008, the project of the International Agency for Research on Cancer which provides contemporary estimates of the incidence, prevalence and mortality from major types of cancers for all countries over the world.7 The Asian geographic area includes these 4 regions of Eastern (China, Japan, Korea and Taiwan), Southeastern (Malaysia, Singapore and Thailand), South Central (India, Iran and Pakistan) and Western (Israel and Turkey) Asia.

Among a total of 3,440 papers searched by those key words, 1,696 papers were excluded from this study because they were not written by English or their subjects were not adults or human. Only 70 studies were included in the final analysis.

Prevalence of Symptom-Based Gastroesophageal Reflux Disease

Details of published studies satisfying the inclusion criteria on the symptom-based GERD (ie, symptoms of heartburn or acid regurgitation occurring at least once a week), in the population-based studies are listed in Table 1. They generally used methods of face-to-face or telephone interviews or the postal questionnaires.

The largest sample group was consisted of Eastern Asia studies, followed by those from South Central Asia (Figure). The prevalence of symptom-based GERD in Eastern Asia was 5.2%-8.5%8-13 from 2005 to 2010, while it was 2.5%-4.8%14-16 before 2005. Most studies in South Central Asia were conducted in Iran. The prevalence of GERD in Iran was 6.3%-18.3%17-20 from 2005 to 2010, which seemed more prevalent than in Eastern Asia. Before 2005, 2 population-based studies from this country with different definitions of GERD also showed similar results.21,22 On the other hand, the time trend of GERD prevalence showed drastic change between 2 cross-sectional surveys of the general population in Singapore in Southeastern Asia. The first survey which was held in 1994 showed the prevalence of GERD by at least monthly symptoms to be around 5.5% ± 1.5%, while it has increased to 10.5% ± 2.0% after 5 years (OR, 2.2; 95% CI, 1.0-5.2; P = 0.05).23 However, the sample size of this study was relatively small and this increased result might also have been attributed to the increased awareness.

The prevalence in Western Asia was found to be the highest among the whole Asian region as represented by 20% in Turkey. One population-based study performed in Israel (2007) also reported the high prevalence of GERD symptoms, including 6.5% of retrosternal burning, 5.2% of retrosternal pain, 10.4% of acid taste in the mouth and 7.9% of the reflux of gastric contents.24

Prevalence of Endoscopic Reflux Esophagitis

The list of studies published regarding the prevalence of endoscopic reflux esophagitis is summarized in Tables 2 and 3. Most endoscopy-based studies were conducted with medical check-up participants or patients having upper gastrointestinal symptoms who visited the referral hospitals. Most of the GERD endoscopic studies were consisted of Eastern Asian studies including Japan, China and Korea. The prevalence of endoscopic reflux esophagitis in Eastern Asia was 3.4%-5.0%25,26 before 2000, with these 2 studies using the definition of reflux esophagitis by Savary-Miller classification, while other 9 studies showed results of 6.6%-15.0%27-31 from 2000 to 2005 and 4.3%-15.7%32-35 after 2005, with the definition by LA classification. However, it is quite uncertain why such a wide range of prevalence has been found for endoscopic reflux esophagitis. There might be some variability in interpreting the endoscopic findings. Furthermore, several studies were conducted in retrospective manner and might have under- or over-estimated the exact prevalence of endoscopic reflux esophagitis.

The intensity and frequency of reflux induced symptoms are poor predictors for finding the presence or the severity of endoscopic mucosal breaks (erosion or ulcer). In the medical check-up studies, the prevalence of GERD based on symptoms like heartburn or acid regurgitations at least once a week was 5.0%-8.2%,31,34,36 which were similar with those of population-based studies.

Asymptomatic reflux esophagitis was reported in 33.6%-84.0% among the subjects with reflux esophagitis.32,34 This finding might be a true reflection of community or caused by the possible over-diagnosis of endoscopic reflux esophagitis by including mild reflux esophagitis or minimal changes.

Non-erosive reflux disease (NERD) has been commonly defined as the presence of classic GERD symptoms in the absence of esophageal mucosal injury which has been detected during the upper endoscopy.37 NERD is considered as the major subcategory of GERD, which has been assumed with an increasingly important role. The prevalence of NERD in medical check-up studies was reported from 3.1% to 4.0%, comprising about 70%-80% of GERD.34,35 Most studies using questionnaires might have over-estimated the prevalence of NERD because their questions might have failed to distinguish the functional heartburn.38 More precise data regarding the epidemiology of NERD are needed.

In referral hospital settings, the prevalence of GERD showed wide range results as followings: 12.4%-31.7% of symptom-based GERD, 2.3%-14.7% of NERD and 7.1%-20.8% of endoscopic reflux esophagitis. In a time trend study in Chinese tertiary hospitals from 2000 to 2007, the prevalence of endoscopic reflux esophagitis increased from 20.7% to 51.0% with the increased numbers of undergoing endoscopy secondary to GERD from 4.9% in 2000 to 14.1% in 2007. However, the prevalence of concomitant GERD symptoms did not significantly change (range, 13.0%-15.1%) in screening endoscopic studies with no significant interval change in the prevalence of NERD.39 Therefore, those authors have suggested that the actual increase in the prevalence of endoscopic reflux esophagitis might be the result of the increased demand for endoscopic investigation of GERD symptoms in some populations, or the better recognition of reflux esophagitis by endoscopists.

Prevalence of Extra-esophageal Syndromes

Although typical manifestations of GERD are heartburn or acid regurgitation, atypical or extra-esophageal symptoms might also be presented including respiratory symptoms, such as chronic cough, asthma or laryngitis, dental erosions, non-cardiac chest pain (NCCP), sleep disturbance and so on.40 These syndromes are usually considered to be multifactorial with GERD as one of the several potential aggravating cofactors.1 Extra-esophageal syndromes rarely occur with concomitant manifestations of the typical esophageal syndrome. Upper endoscopy and ambulatory pH monitoring were used to diagnose reflux in patients with atypical gastroesophageal reflux symptoms, however, these studies have been proved to have poor diagnostic yield.

Extra-esophageal syndromes of GERD in Asia are summarized in Table 4. These data showed a wide range of prevalence or proportion because of the different definition of disease and different conditions of each study.

Two population-based studies in Asia have demonstrated the association between extra-esophageal syndrome and GERD.41,42 The proportion of GERD was significantly higher in subjects with atypical symptoms than in controls (41.6% vs 8.7%, P < 0.05).41 Symptoms as chest pain, dysphagia, globus, asthma, bronchitis, chronic cough and hoarseness were more frequently associated with GERD than controls.42

Both asthma and GERD are common conditions and they often coexist. However, several Western epidemiologic studies have revealed that asthma had been found more frequently in subjects with GERD than the general population.1 The prevalence of GERD was higher in the asthma group compared with controls in one large scale study (n = 1,135), performed in Turkey (25.4% vs 19.4%, P < 0.05).43 The proportion of endoscopic reflux esophagitis in patients with asthma was also higher than controls.44 There have been several studies demonstrating the association between sleep disturbance and GERD. The proportion of sleep dysfunction was 52.5%-56.6% among the patients with GERD, and GERD increased the OR of sleep disturbance to about twice than controls.2,45,46

Dental erosion is an acid-induced loss of dental hard tissue without the involvement of bacteria. Direct contact of regurgitated gastric acid is considered to be the main mechanism of dental erosion in patients with GERD.47 In tertiary hospitals, dental erosions were found in 64.5% among patients with frequent reflux symptoms (3-5 times/wk), 44.4% among subjects with occasional symptoms (1-2 times/wk) and 36.7% among controls (P < 0.05).47

NCCP is a heterogeneous and complex disorder with many potential causes including GERD. NCCP has been common in Asia48 and GERD has also been frequently detected in NCCP, even though the proportions were different according to the diagnostic modalities.48,49

Prevalence of Barrett's Esophagus

Barrett's esophagus is histologically confirmed by specialized intestinal metaplasia.50,51 It is considered to be one of the most important complications of GERD due to its strong association with adenocarcinoma. However, epidemiologic studies have consistently reported that the prevalence of Barrett's esophagus-associated adenocarcinoma is very rare in Asia.52,53 The prevalence of Barrett's esophagus was reported as 0.06%-0.84%29,54 in medical check-up and 0.31%-2.00%39,55-60 in the referral hospital settings (Table 5). The proportion of Barrett's esophagus was 7.3%61 in patients with GERD and 2.4%62 in those with heartburn symptoms. Importantly, esophageal adenocarcinoma is often found even without any medical history of reflux symptoms.63 Although GERD symptoms is considered to be one of the most important risk factors of Barrett's esophagus,54-56 only 60.1% of subjects who had received the medical check-up were found to have GERD symptoms.57

In the Western world, esophageal adenocarcinoma has become one of the increasing cancers, in parallel with the increased prevalence of GERD and its major determinant, obesity.64,65 Such increase in the occurrence of Barrett's esophagus has not yet been observed in Asia. Epidemiologic changes of GERD in Asia seem to be correlated with economic or environmental effects, Helicobacter pylori infections, nutritional changes, and also the geographic and ethnic differences.53,66 The general low-fat diet of Asian, their smaller body mass and also their higher prevalence of Helicobacter pylori might be related with the lower prevalence of GERD compared to Western peoples.53 However, their rapid economic growth, changes of eating habits and also the growing number of obesity in people would induce many changes in the epidemiology of Barrett's esophagus and esophageal adenocarcinoma in the future.

In conclusion, many robust studies about GERD in Asia have been published during recent decades. Population-based studies showed that the prevalence of GERD has been increased in Eastern Asia, but still lower than those of the Western population. The prevalence of GERD in Southeast and Western Asia was higher than in Eastern Asia. The prevalence of endoscopic reflux esophagitis in Eastern Asia seemed to increase in participants who have received the medical check-up. In Asia, only few and limited studies have been reported regarding the proportion of extra-esophageal syndromes such as asthma, sleep disturbance, non-cardiac chest pain and dental erosion, which was found to be significantly higher in the GERD patient group than controls. On the other hand, the prevalence of Barrett's esophagus was found to be relatively low.

Based on the distinct genetic characteristics compared from the Western people, and rapid changes of socio-economic environments, this kind of study observing and investigating the epidemiologic changes of GERD in Asia would be a good model to understand the underlying pathogenesis of GERD.

Figures
Fig. 1. The prevalence of gastroesophageal reflux disease in Asian population-based study. Gastroesophageal reflux disease (GERD) is defined as having heartburn or acid regurgitation at least weekly. *Study conducted in subjects with medical check-up, **GERD, retrosternal burning sensation or acid regurgitation at least once a month.

Tables
Table. 1. Population-Based Study of Gastroesophageal Reflux Disease in Asia

GERD, gastroesophageal reflux disease; RDQ, Reflux Disease Questionnaire, HRQOL; health-related quality of life; IBS, irritable bowel syndrome; SGER, symptomatic gastroesophageal reflux; BMI, body mass index.

Table. 2. Epidemiology of Gastroesophageal Reflux Disease in Asian Medical Check-up People

GERD, gastroesophageal reflux disease; RDQ, Reflux Disease Questionnaire, HRQOL; health-related quality of life; IBS, irritable bowel syndrome; SGER, symptomatic gastroesophageal reflux; BMI, body mass index.

Table. 3. Epidemiology of Gastroesophageal Reflux Disease in Asian Referral Hospital

GERD, gastroesophageal reflux disease; RDQ, Reflux Disease Questionnaire, HRQOL; health-related quality of life; IBS, irritable bowel syndrome; SGER, symptomatic gastroesophageal reflux; BMI, body mass index.

Table. 4. Extra-esophageal Syndrome of Gastroesophageal Reflux Disease in Asia

GERD, gastroesophageal reflux disease; RDQ, Reflux Disease Questionnaire, HRQOL; health-related quality of life; IBS, irritable bowel syndrome; SGER, symptomatic gastroesophageal reflux; BMI, body mass index.

Table. 5. Epidemiology of Barrett's Esophagus in Asia

GERD, gastroesophageal reflux disease; RDQ, Reflux Disease Questionnaire, HRQOL; health-related quality of life; IBS, irritable bowel syndrome; SGER, symptomatic gastroesophageal reflux; BMI, body mass index.

References
  1. Vakil N, van Zanten SV, Kahrilas P, Dent J, Jones R; Global Consensus Group. The Montreal definition and classification of gastroesophageal reflux disease: a global evidence-based consensus. Am J Gastroenterol 2006;101:1900-1920.
    Pubmed CrossRef
  2. Chen MJ, Wu MS, Lin JT, et al. Gastroesophageal reflux disease and sleep quality in a Chinese population. J Formos Med Assoc 2009;108:53-60.
    CrossRef
  3. Kang JY. Systematic review: geographical and ethnic differences in gastro-oesophageal reflux disease. Aliment Pharmacol Ther 2004;20:705-717.
    Pubmed CrossRef
  4. El-Serag HB. Time trends of gastroesophageal reflux disease: a systematic review. Clin Gastroenterol Hepatol 2007;5:17-26.
    Pubmed CrossRef
  5. Fock KM, Talley NJ, Fass R, et al. Asia-Pacific consensus on the management of gastroesophageal reflux disease: update. J Gastroenterol Hepatol 2008;23:8-22.
    Pubmed CrossRef
  6. Goh KL, Chang CS, Fock KM, Ke M, Park HJ, Lam SK. Gastrooesophageal reflux disease in Asia. J Gastroenterol Hepatol 2000;15:230-238.
    Pubmed CrossRef
  7. GLOBOCAN 2008: Cancer incidence and mortality worldwide in 2008. International agency for research on cancer; 2008. Available from http://globocan.iarc.fr.
  8. He J, Ma X, Zhao Y, et al. A population-based survey of the epidemiology of symptom-defined gastroesophageal reflux disease: the Systematic Investigation of Gastrointestinal Diseases in China. BMC Gastroenterol 2010;10:94.
    Pubmed KoreaMed CrossRef
  9. Wang R, Yan X, Ma XQ, et al. Burden of gastroesophageal reflux disease in Shanghai, China. Dig Liver Dis 2009;41:110-115.
    Pubmed CrossRef
  10. Lee SY, Lee KJ, Kim SJ, Cho SW. Prevalence and risk factors for overlaps between gastroesophageal reflux disease, dyspepsia, and irritable bowel syndrome: a population-based study. Digestion 2009;79:196-201.
    Pubmed CrossRef
  11. Yang SY, Lee OY, Bak YT, et al. Prevalence of gastroesophageal reflux disease symptoms and uninvestigated dyspepsia in Korea: a population-based study. Dig Dis Sci 2008;53:188-193.
    Pubmed CrossRef
  12. Li YM, Du J, Zhang H, Yu CH. Epidemiological investigation in outpatients with symptomatic gastroesophageal reflux from the Department of Medicine in Zhejiang Province, east China. J Gastroenterol Hepatol 2008;23:283-289.
    Pubmed CrossRef
  13. Chen M, Xiong L, Chen H, Xu A, He L, Hu P. Prevalence, risk factors and impact of gastroesophageal reflux disease symptoms: a population-based study in South China. Scand J Gastroenterol 2005;40:759-767.
    Pubmed CrossRef
  14. Wong WM, Lai KC, Lam KF, et al. Prevalence, clinical spectrum and health care utilization of gastro-oesophageal reflux disease in a Chinese population: a population-based study. Aliment Pharmacol Ther 2003;18:595-604.
    Pubmed CrossRef
  15. Jeong JJ, Choi MG, Cho YS, et al. Chronic gastrointestinal symptoms and quality of life in the Korean population. World J Gastroenterol 2008;14:6388-6394.
    Pubmed KoreaMed CrossRef
  16. Cheung TK, Lam KF, Hu WH, et al. Positive association between gastro-oesophageal reflux disease and irritable bowel syndrome in a Chinese population. Aliment Pharmacol Ther 2007;25:1099-1104.
    Pubmed CrossRef
  17. Solhpour A, Pourhoseingholi MA, Soltani F, et al. Gastro-esophageal reflux symptoms and body mass index: no relation among the Iranian population. Indian J Gastroenterol 2008;27:153-155.
    Pubmed
  18. Nasseri-Moghaddam S, Mofid A, Ghotbi MH, et al. Epidemiological study of gastro-oesophageal reflux disease: reflux in spouse as a risk factor. Aliment Pharmacol Ther 2008;28:144-153.
    Pubmed CrossRef
  19. Somi MH, Farhang S, Mirinezhad K, et al. Prevalence and precipitating factors of gastroesophageal reflux disease in a young population of Tabriz, Northwest of Iran. Saudi Med J 2006;27:18781881.
  20. Nouraie M, Razjouyan H, Assady M, Malekzadeh R, Nasseri-Moghaddam S. Epidemiology of gastroesophageal reflux symptoms in Tehran, Iran: a population-based telephone survey. Arch Iran Med 2007;10:289-294.
    Pubmed
  21. Saberi-Firoozi M, Khademolhosseini F, Yousefi M, Mehrabani D, Zare N, Heydari ST. Risk factors of gastroesophageal reflux disease in Shiraz, southern Iran. World J Gastroenterol 2007;13:5486-5491.
    Pubmed KoreaMed CrossRef
  22. Ehsani MJ, Maleki I, Mohammadzadeh F, Mashayekh A. Epidemiology of gastroesophageal reflux disease in Tehran, Iran. J Gastroenterol Hepatol 2007;22:1419-1422.
    Pubmed CrossRef
  23. Lim SL, Goh WT, Lee JM, Ng TP, Ho KY; Community Medicine GI Study Group. Changing prevalence of gastroesophageal reflux with changing time: longitudinal study in an Asian population. J Gastroenterol Hepatol 2005;20:995-1001.
    Pubmed CrossRef
  24. Sperber AD, Halpern Z, Shvartzman P, et al. Prevalence of GERD symptoms in a representative Israeli adult population. J Clin Gastroenterol 2007;41:457-461.
    Pubmed CrossRef
  25. Lee SJ, Song CW, Jeen YT, et al. Prevalence of endoscopic reflux esophagitis among Koreans. J Gastroenterol Hepatol 2001;16:373376.
    CrossRef
  26. Lien HC, Chang CS, Yeh HZ, et al. Increasing prevalence of erosive esophagitis among Taiwanese aged 40 years and above: a comparison between two time periods. J Clin Gastroenterol 2009;43:926-932.
    Pubmed CrossRef
  27. Fujimoto K, Iwakiri R, Okamoto K, et al. Characteristics of gastroesophageal reflux disease in Japan: increased prevalence in elderly women. J Gastroenterol 2003;38(suppl 15):3-6.
    Pubmed
  28. Fujiwara Y, Higuchi K, Shiba M, et al. Association between gastroesophageal flap valve, reflux esophagitis, Barrett's epithelium, and atrophic gastritis assessed by endoscopy in Japanese patients. J Gastroenterol 2003;38:533-539.
    Pubmed CrossRef
  29. Tseng PH, Lee YC, Chiu HM, et al. Prevalence and clinical characteristics of Barrett's esophagus in a Chinese general population. J Clin Gastroenterol 2008;42:1074-1079.
    Pubmed CrossRef
  30. Lee HL, Eun CS, Lee OY, et al. Association between GERD-related erosive esophagitis and obesity. J Clin Gastroenterol 2008;42:672-675.
    Pubmed CrossRef
  31. Kang MS, Park DI, Oh SY, et al. Abdominal obesity is an independent risk factor for erosive esophagitis in a Korean population. J Gastroenterol Hepatol 2007;22:1656-1661.
    Pubmed CrossRef
  32. Peng S, Cui Y, Xiao YL, et al. Prevalence of erosive esophagitis and Barrett's esophagus in the adult Chinese population. Endoscopy 2009;41:1011-1017.
    Pubmed CrossRef
  33. Yamagishi H, Koike T, Ohara S, et al. Clinical characteristics of gastroesophageal reflux disease in Japan. Hepatogastroenterology 2009;56:1032-1034.
    Pubmed
  34. Kim N, Lee SW, Cho SI, et al. The prevalence of and risk factors for erosive oesophagitis and non-erosive reflux disease: a nationwide multicentre prospective study in Korea. Aliment Pharmacol Ther 2008;27:173-185.
    Pubmed CrossRef
  35. Noh YW, Jung HK, Kim SE, Jung SA. Overlap of erosive and non-erosive reflux diseases with functional gastrointestinal disorders according to Rome III criteria. J Neurogastroenterol Motil 2010;16:148-156.
    Pubmed KoreaMed CrossRef
  36. Kaji M, Fujiwara Y, Shiba M, et al. Prevalence of overlaps between GERD, FD and IBS and impact on health-related quality of life. J Gastroenterol Hepatol 2010;25:1151-1156.
    Pubmed CrossRef
  37. Hershcovici T, Fass R. Nonerosive reflux disease (NERD) - an update. J Neurogastroenterol Motil 2010;16:8-21.
    Pubmed KoreaMed CrossRef
  38. Modlin IM, Hunt RH, Malfertheiner P, et al. Non-erosive reflux disease - defining the entity and delineating the management. Digestion 2008;78(suppl 1):1-5.
    CrossRef
  39. Chen MJ, Lee YC, Chiu HM, Wu MS, Wang HP, Lin JT. Time trends of endoscopic and pathological diagnoses related to gastroesophageal reflux disease in a Chinese population: eight years single institution experience. Dis Esophagus 2010;23:201-207.
    Pubmed CrossRef
  40. Koop H, Schepp W, Müller-Lissner S, et al. Consensus conference of the DGVS on gastroesophageal reflux. Z Gastroenterol 2005;43:163-164.
    Pubmed CrossRef
  41. Cho YS, Choi MG, Jeong JJ, et al. Prevalence and clinical spectrum of gastroesophageal reflux: a population-based study in Asan-si, Korea. Am J Gastroenterol 2005;100:747-753.
    Pubmed CrossRef
  42. Wang JH, Luo JY, Dong L, Gong J, Tong M. Epidemiology of gastroesophageal reflux disease: a general population-based study in Xi'an of Northwest China. World J Gastroenterol 2004;10:16471651.
    CrossRef
  43. Bor S, Kitapcioglu G, Solak ZA, Ertilav M, Erdinc M. Prevalence of gastroesophageal reflux disease in patients with asthma and chronic obstructive pulmonary disease. J Gastroenterol Hepatol 2010;25:309-313.
    Pubmed CrossRef
  44. Shimizu Y, Dobashi K, Kobayashi S, et al. High prevalence of gastroesophageal reflux disease with minimal mucosal change in asthmatic patients. Tohoku J Exp Med 2006;209:329-336.
    Pubmed CrossRef
  45. Fujiwara Y, Kohata Y, Kaji M, et al. Sleep dysfunction in Japanese patients with gastroesophageal reflux disease: prevalence, risk factors, and efficacy of rabeprazole. Digestion 2010;81:135-141.
    Pubmed CrossRef
  46. Kusano M, Kouzu T, Kawano T, Ohara S. Nationwide epidemiological study on gastroesophageal reflux disease and sleep disorders in the Japanese population. J Gastroenterol 2008;43:833-841.
    Pubmed CrossRef
  47. Wang GR, Zhang H, Wang ZG, Jiang GS, Guo CH. Relationship between dental erosion and respiratory symptoms in patients with gastro-oesophageal reflux disease. J Dent 2010;38:892-898.
    Pubmed CrossRef
  48. Bor S, Mandiracioglu A, Kitapcioglu G, Caymaz-Bor C, Gilbert RJ. Gastroesophageal reflux disease in a low-income region in Turkey. Am J Gastroenterol 2005;100:759-765.
    Pubmed CrossRef
  49. Mohd H, Qua CS, Wong CH, Azman W, Goh KL. Non-cardiac chest pain: prevalence of reflux disease and response to acid suppression in an Asian population. J Gastroenterol Hepatol 2009;24:288-293.
    Pubmed CrossRef
  50. Hirota WK, Loughney TM, Lazas DJ, Maydonovitch CL, Rholl V, Wong RK. Specialized intestinal metaplasia, dysplasia, and cancer of the esophagus and esophagogastric junction: prevalence and clinical data. Gastroenterology 1999;116:277-285.
    CrossRef
  51. Spechler SJ. The columnar-lined esophagus. History, terminology, and clinical issues. Gastroenterol Clin North Am 1997;26:455-466.
    CrossRef
  52. Tu CH, Lee CT, Perng DS, Chang CC, Hsu CH, Lee YC. Esophageal adenocarcinoma arising from Barrett's epithelium in Taiwan. J Formos Med Assoc 2007;106:664-668.
    CrossRef
  53. Hongo M, Nagasaki Y, Shoji T. Epidemiology of esophageal cancer:Orient to Occident. Effects of chronology, geography and ethnicity. J Gastroenterol Hepatol 2009;24:729-735.
    Pubmed CrossRef
  54. Kim JH, Rhee PL, Lee JH, et al. Prevalence and risk factors of Barrett's esophagus in Korea. J Gastroenterol Hepatol 2007;22:908912.
    Pubmed CrossRef
  55. Xiong LS, Cui Y, Wang JP, et al. Prevalence and risk factors of Barrett's esophagus in patients undergoing endoscopy for upper gastrointestinal symptoms. J Dig Dis 2010;11:83-87.
    Pubmed CrossRef
  56. Lee IS, Choi SC, Shim KN, et al. Prevalence of Barrett's esophagus remains low in the Korean population: nationwide cross-sectional prospective multicenter study. Dig Dis Sci 2010;55:1932-1939.
    Pubmed CrossRef
  57. Park JJ, Kim JW, Kim HJ, et al. The prevalence of and risk factors for Barrett's esophagus in a Korean population: a nationwide multicenter prospective study. J Clin Gastroenterol 2009;43:907-914.
    Pubmed CrossRef
  58. Odemiş B, Ciçek B, Zengin NI, et al. Barrett's esophagus and endoscopically assessed esophagogastric junction integrity in 1000 consecutive Turkish patients undergoing endoscopy: a prospective study. Dis Esophagus 2009;22:649-655.
    Pubmed CrossRef
  59. Gadour MO, Ayoola EA. Barrett's oesophagus and oesophageal cancer in Saudi Arabia. Trop Gastroenterol 1999;20:111-115.
    Pubmed
  60. Yeh C, Hsu CT, Ho AS, Sampliner RE, Fass R. Erosive esophagitis and Barrett's esophagus in Taiwan: a higher frequency than expected. Dig Dis Sci 1997;42:702-706.
    Pubmed CrossRef
  61. Fouad YM, Makhlouf MM, Tawfik HM, el-Amin H, Ghany WA, el-Khayat HR. Barrett's esophagus: prevalence and risk factors in patients with chronic GERD in Upper Egypt. World J Gastroenterol 2009;15:3511-3515.
    Pubmed KoreaMed CrossRef
  62. Bafandeh Y, Esmaili H, Aharizad S. Endoscopic and histologic findings in Iranian patients with heartburn. Indian J Gastroenterol 2005;24:236-238.
    Pubmed
  63. Bytzer P, Christensen PB, Damkier P, Vinding K, Seersholm N. Adenocarcinoma of the esophagus and Barrett's esophagus: a populationbased study. Am J Gastroenterol 1999;94:86-91.
    Pubmed CrossRef
  64. Blot WJ, Devesa SS, Kneller RW, Fraumeni JF Jr. Rising incidence of adenocarcinoma of the esophagus and gastric cardia. JAMA 1991;265:1287-1289.
    Pubmed CrossRef
  65. Devesa SS, Blot WJ, Fraumeni JF Jr. Changing patterns in the incidence of esophageal and gastric carcinoma in the United States. Cancer 1998;83:2049-2053.
    CrossRef
  66. Blaser MJ. Hypothesis: the changing relationships of Helicobacter pylori and humans: implications for health and disease. J Infect Dis 1999;179:1523-1530.
    Pubmed CrossRef
  67. Ma XQ, Cao Y, Wang R, et al. Prevalence of, and factors associated with, gastroesophageal reflux disease: a population-based study in Shanghai, China. Dis Esophagus 2009;22:317-322.
    Pubmed CrossRef
  68. Ho KY, Kang JY, Seow A. Prevalence of gastrointestinal symptoms in a multiracial Asian population, with particular reference to refluxtype symptoms. Am J Gastroenterol 1998;93:1816-1822.
    Pubmed CrossRef
  69. Mostaghni A, Mehrabani D, Khademolhosseini F, et al. Prevalence and risk factors of gastroesophageal reflux disease in Qashqai migrating nomads, southern Iran. World J Gastroenterol 2009;15:961-965.
    Pubmed KoreaMed CrossRef
  70. Kitapçioğlu G, Mandiracioğlu A, Caymaz Bor C, Bor S. Overlap of symptoms of dyspepsia and gastroesophageal reflux in the community. Turk J Gastroenterol 2007;18:14-19.
    Pubmed
  71. Matsuzaki J, Suzuki H, Iwasaki E, Yokoyama H, Sugino Y, Hibi T. Serum lipid levels are positively associated with non-erosive reflux disease, but not with functional heartburn. Neurogastroenterol Motil 2010;22:965-970, e251.
  72. Yamagishi H, Koike T, Ohara S, et al. Prevalence of gastroesophageal reflux symptoms in a large unselected general population in Japan. World J Gastroenterol 2008;14:1358-1364.
    Pubmed KoreaMed CrossRef
  73. Fujiwara Y, Higuchi K, Watanabe Y, et al. Prevalence of gastroesophageal reflux disease and gastroesophageal reflux disease symptoms in Japan. J Gastroenterol Hepatol 2005;20:26-29.
    Pubmed CrossRef
  74. Sakaguchi M, Oka H, Hashimoto T, et al. Obesity as a risk factor for GERD in Japan. J Gastroenterol 2008;43:57-62.
    Pubmed CrossRef
  75. Du J, Liu J, Zhang H, Yu CH, Li YM. Risk factors for gastroesophageal reflux disease, reflux esophagitis and non-erosive reflux disease among Chinese patients undergoing upper gastrointestinal endoscopic examination. World J Gastroenterol 2007;13:6009-6015.
    Pubmed KoreaMed CrossRef
  76. Miyamoto M, Haruma K, Kuwabara M, Nagano M, Okamoto T, Tanaka M. High incidence of newly-developed gastroesophageal reflux disease in the Japanese community: a 6-year follow-up study. J Gastroenterol Hepatol 2008;23:393-397.
    Pubmed CrossRef
  77. Mishima I, Adachi K, Arima N, et al. Prevalence of endoscopically negative and positive gastroesophageal reflux disease in the Japanese. Scand J Gastroenterol 2005;40:1005-1009.
    Pubmed CrossRef
  78. Okamoto K, Iwakiri R, Mori M, et al. Clinical symptoms in endoscopic reflux esophagitis: evaluation in 8031 adult subjects. Dig Dis Sci 2003;48:2237-2241.
    Pubmed CrossRef
  79. Chang CS, Poon SK, Lien HC, Chen GH. The incidence of reflux esophagitis among the Chinese. Am J Gastroenterol 1997;92:668671.
  80. Haruma K, Hamada H, Mihara M, et al. Negative association between Helicobacter pylori infection and reflux esophagitis in older patients:case-control study in Japan. Helicobacter 2000;5:24-29.
    Pubmed CrossRef
  81. Rosaida MS, Goh KL. Gastro-oesophageal reflux disease, reflux oesophagitis and non-erosive reflux disease in a multiracial Asian population:a prospective, endoscopy based study. Eur J Gastroenterol Hepatol 2004;16:495-501.
    CrossRef
  82. Ho KY, Chan YH, Kang JY. Increasing trend of reflux esophagitis and decreasing trend of Helicobacter pylori infection in patients from a multiethnic Asian country. Am J Gastroenterol 2005;100:19231928.
    Pubmed CrossRef
  83. Yarandi SS, Nasseri-Moghaddam S, Mostajabi P, Malekzadeh R. Overlapping gastroesophageal reflux disease and irritable bowel syndrome:increased dysfunctional symptoms. World J Gastroenterol 2010;16:1232-1238.
    Pubmed KoreaMed CrossRef
  84. Jafri N, Yakoob J, Islam M, Manzoor S, Jalil A, Hashmi F. Perception of gastroesophageal reflux disease in urban population in Pakistan. J Coll Physicians Surg Pak 2005;15:532-534.
    Pubmed
  85. Al-Humayed SM, Mohamed-Elbagir AK, Al-Wabel AA, Argobi YA. The changing pattern of upper gastro-intestinal lesions in southern Saudi Arabia: an endoscopic study. Saudi J Gastroenterol 2010;16:35-37.
    Pubmed KoreaMed CrossRef
  86. Takenaka R, Matsuno O, Kitajima K, et al. The use of frequency scale for the symptoms of GERD in assessment of gastro-oesophageal reflex symptoms in asthma. Allergol Immunopathol (Madr) 2010;38:20-24.
    Pubmed CrossRef
  87. Chunlertrith K, Boonsawat W, Zaeoue U. Prevalence of gastroesophageal reflux symptoms in asthma patients at Srinagarind Hospital. J Med Assoc Thai 2005;88:668-671.
    Pubmed
  88. Al-Asoom L, Al-Rubaish AM, El-Munshid HA, Al-Nafaie AN, Bukharie HA, Abdulrahman IS. Gastroesophageal reflux in bronchial asthma patients. A clinical note. Saudi Med J 2003;24:13641369.
  89. Nakase H, Itani T, Mimura J, et al. Relationship between asthma and gastro-oesophageal reflux: significance of endoscopic grade of reflux oesophagitis in adult asthmatics. J Gastroenterol Hepatol 1999;14:715-722.
    Pubmed CrossRef
  90. Gharaibeh TM, Jadallah K, Jadayel FA. Prevalence of temporomandibular disorders in patients with gastroesophageal reflux disease: a case-controlled study. J Oral Maxillofac Surg 2010;68:1560-1564.
    Pubmed CrossRef
  91. Toros SZ, Toros AB, Yüksel OD, Ozel L, Akkaynak C, Naiboglu B. Association of laryngopharyngeal manifestations and gastroesophageal reflux. Eur Arch Otorhinolaryngol 2009;266:403-409.
    Pubmed CrossRef
  92. Qua CS, Wong CH, Gopala K, Goh KL. Gastro-oesophageal reflux disease in chronic laryngitis: prevalence and response to acid-suppressive therapy. Aliment Pharmacol Ther 2007;25:287-295.
    Pubmed CrossRef


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