Gastro-oesophageal reflux disease is a common chronic disorder prevalent in many countries.
Epidemiologic studies of GORD in the West date back to the late 1970s with an increasing trend in the prevalence over the last two decades.4,17,57,58 The increasing incidence and prevalence in recent decades may be explained by the attention dedicated to its study globally through increased awareness of the disease and improved diagnostic techniques and rising incidence of obesity.9
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Symptoms of GORD, at least weekly heartburn and/or regurgitation, affect 10% –20% of the population in the Western world and around 5% of the population in Asia.2,3 The range of GORD prevalence estimates defined as at least weekly heartburn and/or regurgitation is highest in North America and Europe, reported by Sharma et al at 10% - 30%.4 Similarly defined in a systematic review of population-based studies by El-Serag et al, it was 18.1% - 27.8% in North America, 8.8% – 25.9% in Europe, 2.5% – 7.8% in East Asia, 8.7% – 33.1%
in the Middle East, 11.6% in Australia and 23.0% in South America. Incidence per 1000 person-years was approximately 5 in the overall UK and US populations.57 Data from Africa, Indian subcontinent, South America and the Middle East are sparse.4,8
2.2.1 United States
Heartburn afflicts nearly two thirds of US adults at some point of their lives and accounts for 4-5 million physician office visits every year.14 An estimated 44% of the United States (US) adult population (61million) have heartburn, the hallmark of acid regurgitation, at least once a month; age- and gender-adjusted prevalence of weekly heartburn or acid regurgitation approaches 20%.5,7 Approximately 14% of Americans have GORD symptoms weekly, and 7% (over 25 million) have symptoms daily.3,5,6
In a population-based study in Argentina, South America by Chiocca et al, 61.2% of participants reported reflux experience of at least once in the previous year; less than once a month was 20.5%; about once a month was 16.8%; several times a week was 9.6%; and daily was 3.1%.59 The prevalence of at least weekly heartburn and/or regurgitation was 23.0%; at least weekly heartburn was 16.9% and of at least weekly regurgitation was 16.5%. The population for this study was selected from working and elderly populations (18 - 80 years) in companies and community centres, and therefore did not include unemployed individuals of working age. Moraes-Filho et al in Brazilian study that involved 22 cities and enrolled 13,959 adults reported a prevalence of 11.9% for at least weekly symptoms.60
32 2.2.2 Europe
There appears to be a lower prevalence of GORD, defined by weekly heartburn and/or regurgitation, in Europe compared to North America.17 In the Kalixandra study in Kalix and Haparanda, North Sweden by Ronkainen et al, weekly heartburn and/or regurgitation were experienced by 259 (25.9%) of participants.30 It was reported to be 8.8 to 25.9% by El – Serag with a tendency for GORD to be more prevalent in northern than southern Europe.57 2.2.3 Middle East
In Tehran, Iran, Nasseri-Moghaddam et al and Nouraie et al in separate studies reported the prevalence of at least weekly heartburn to be 2.2% - 9.6% and 7.2% - 12.2% for regurgitation respectively.61,62
In Turkey, Kitapcioglu et al reported the results of a 1998–1999 survey (published in 2007) of 630 individuals aged over 20 years in the Asian town of Menderes. The prevalence of at least weekly heartburn and/or regurgitation was 20%; of at least weekly heartburn was 10%;
and of at least weekly regurgitation was 15.6%.63
In Israel, Sperber et al reported in a strictly Jewish population a 9.3% prevalence of at least weekly heartburn and/or regurgitation.64 The Jewish population is approximately 75%, thus, the result is not generalisable to the population of Israel as a whole.64
2.2.4 Asia
Wong and Kinoshita in a systematic review reported a prevalence of 2.5% to 6.7% of GORD in adults with at least weekly symptoms of heartburn and/or acid regurgitation across eastern and southeastern Asia.65 When focusing on studies using validated symptom questionnaires only, the reported prevalence ranged from 2.5% to 4.8%. El –Serag et al reported a prevalence of 2.5% - 7.8% in Eastern Asian population.57
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Chen et al reported the results of a 2003 survey (Published 2005) of 3338 people aged 18 – 90 years and randomly selected from the cities of Guangzhou and Huizhou in southern China.66 The prevalence of at least weekly heartburn was 2.2%; of at least weekly regurgitation was 7.0%; and that of at least weekly heartburn and/or regurgitation was 7.8%.
Also in China, a survey carried out in individuals aged 18 to 80 years randomly sampled from urban and rural areas of Shanghai, Beijing, Wuhan, Xi’an and Guangzhou reported 5.2%
prevalence of at least weekly heartburn and/or regurgitation and varying between the different regions from 3.2% to 7.5%.67 The prevalence of at least weekly heartburn in the overall population was 1.8% while it was 4.2% for regurgitation. The reported overall prevalence of Montreal-defined GORD was 3.1%, varying between 1.7% and 5.1% in the different regions.1,67
In Asan-si in Chungcheongnam-do Province, South Korea, Cho et al reported 3.5%
prevalence of at least weekly heartburn and/or regurgitation among participants aged 18 to 69 years.68 The prevalence of at least weekly heartburn was 2.0% and regurgitation 2.0%.
2.2.5 Australasia
Eslick et al assessed the prevalence of GORD among 672 individuals living in western Sydney and reported 11.6% prevalence of at least weekly heartburn and/or regurgitation.69 2.2.6 Africa
GORD was previously thought to be rare in Africans, studies actually indicate that it is common though epidemiologic data from Africa, Indian subcontinent, South America and the Middle East are sparse.4,8 Segal and Dent pointed out the possible reasons for underreporting such as: patients may not present to hospitals; inadequate health care services including endoscopic services; less than optimum methods of data collection and maintenance and the average life expectancy in sub-Saharan Africa is much lower than in industrialized countries.5,10
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A study in 2005 by Van Rensburg et al in South Africa showed that most patients (91%) had experienced heartburn symptoms for over a year (1-5years 48%, > 5 years 43.2%) and in two-thirds (66%) the duration of current episode was 6 months or less.9 Over half of patients (54%) had experienced symptoms on five or more occasions in the previous 7 days (1-2days 18.4%, 3 - 4 days 28%, ≥ 5 days 53.6%). Most patients (62%) described their symptoms as being severe during this period. The mean age of participants was 46 ± 12.3 years with more females (74.4%) than males (25.6%).9
A 2008 study amongst clinical Medical Students in Enugu campus by Nwokediuko showed a 26.34% prevalence of GORD with an association with caffeine-containing substances (coffee and kola-nuts).10 Similarly, Ntagiribi et al in Burundi reported 27.8% prevalence of heartbun in a students’ population.15 Assi and colleagues in Abidjan, Cote d’Ivoire, reported a 9.2%
prevalence of heartburn of once weekly in a population-based study with a mean age of 28 ± 9 years. The male-to-female ratio was 1:1.2 (5:6).14
2.2.7 Ethnic and racial differences within countries
Studies in multiracial populations have the potential to elucidate the racial differences in GORD. In United States of America, EL-Serag et al in a cross-sectional study used the GerdQ tool followed by endoscopy among employees at a Veterans Affair Medical Centre.70 The questionnaires were returned by 54% of individuals (43% black, 34% white, 23% other race) and endoscopy was performed in 215 of the 496 returnees (43%). There was no difference in the frequency of weekly heartburn and/or regurgitation between the different racial groups (blacks 29%, whites 28%, other 25%).Nonetheless,GORD is reported to be more common in Caucasians than blacks.4 Another endoscopy-based study from Kuala Lumpur that studied 1,000 GORD patients prospectively showed that Indian and Malay race were independent risk factors for reflux symptoms and the presence of non-erosive reflux disease but differences between the races was not reported.71
35 2.2.8 Gender differences in GORD
There is no sex predilection in GORD.72 El-Serag et al found no evidence that male sex was associated with GORD.57 However, GORD has been observed to be slightly more common in women, often multiparous, with most affected individuals above 50 years of age and many are obese. It is worthy of note that oesophagitis is commoner in females nonetheless with a male – to – female ratio for 2:2 – 3:1.72
2.2.9 Age and GORD
Two systematic reviews found little evidence that age was associated with GORD.57,73 2.2.10 Potential reasons for differences in epidemiology and ethnic variations of GORD There are several potential explanations for the differences in reported prevalence rates in different countries.
Cultural and language differences in symptom perception and interpretation exists.74 The term
"heartburn" is not universally understood especially where there is no direct translation of the word "heartburn" in other languages. Spechler et al, in a multiethnic study, showed that this term was understood by only 35% of white American subjects and the figure dropped to 13%
for Asians patients.74 It is worth noting that not all studies have assessed the prevalence of GORD using validated language and ethnic sensitive tools/questionnaires and the use of a consistent definition of GORD has frequently been lacking. In fact, the lack of a universal definition may account not only for the variability in the prevalence of GORD but possibly the rate of complications such as erosive oesophagitis and Barret’s oesophagus.
Socioeconomic and lifestyle changes could play a role. Lower gastric acid secretion (maximal and basal acid output), lower body mass index, differences in consumption of dietary fat, and use of alcohol and tobacco may all be relevant factors explaining differences in prevalence rates.
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Differences may also be attributed to referral patterns, diagnostic practices, and physician recognition along with increased awareness of the disease and improved diagnostic techniques. Ethnic or racial differences may result in differences between groups in symptom reporting and patients' willingness to undergo endoscopy. Differences in physician referral selection bias, based on the patient's ethnic background for endoscopic examination may skew a centre’s reporting. Changes in definitions and physician education impacts diagnosis which in turn impacts on estimates of disease prevalence.
2.2.11 Economic burden of GORD
Gastro-oesophageal reflux disease is associated with a huge economic burden in western countries.4 The direct costs per year associated with GORD in terms of consultation, referral, and treatment reach almost $10 billion in the United States whereas indirect costs caused by reduced work productivity are estimated to be as much as $75 billion.17
A further increase in the worldwide prevalence of GORD with increased awareness of the disease and improved diagnostic techniques would therefore represent a significant financial burden for both healthcare systems and employers. Furthermore, an increase in the prevalence of GORD might consequently lead to an increase in the incidence of these more serious conditions like Barrett’s oesophagus and oesophageal adenocarcinoma. Thus, appropriate and cost-effective GORD management should be considered.