Prevalence of gastroesophageal reflux symptoms in a large unselected general population in Japan

Natural history of gastroesophageal reflux: A prospective cohort study in a stratified, randomized population in Beijing

OBJECTIVE

To explore the natural history of and risk factors for gastroesophageal reflux (GER) in a prospective cohort in Beijing, China.

METHODS

We selected adult participants using a stratified randomized method and performed initial surveys in 1996 and the current survey in 2008. Well-trained investigators administered the survey questionnaire using face-to-face interviews. Reflux symptoms were evaluated by their intensity and frequency. GER was defined as heartburn, acid reflux, and food regurgitation at least once a week, and monthly reflux was defined as at least one of the above symptoms occurring 1-3 days per month.

RESULTS

The resurvey response rate was 47.8% (1189/2486). Over 12 years, 66.9% of the respondents remained unchanged, and one-third changed, with a GER new onset rate of 7.0 per 1000 person-years and a GER disappearance rate of 64.6 per 1000 person-years. This kept the GER prevalence stable at 8.2% to 9.5% (P = 0.28). GER and monthly reflux exhibited significant differences in their tendency to persist or become aggravated to GER (22.4% vs 11.9%, P = 0.02). Participants who initially had single, mild to moderate, daily GER were more likely to recover from reflux over time. Participants with persistent and aggravated GER had more severe heartburn and acid reflux than those with new-onset GER in the current survey. Multiple logistic regression analysis showed that emotional depression is a risk factor for GER aggravation (odds ratio 3.52, 95% confidence interval 1.43-8.67, P = 0.006).

CONCLUSION

The initial symptom profile of reflux determines the outcome of GER over time.

Prevalence and factors associated with gastroesophageal reflux disease in southern India: A community-based study

BACKGROUND AND AIM

Gastroesophageal reflux disease (GERD) is common worldwide with significant expenditure for health care. Community-based data on the prevalence of GERD in India remains scarce. This study was conducted to determine the prevalence of GERD and to identify potential associations.

METHODS

A community-based survey of adults (aged ≥18 years) was done through population proportionate to size sampling in urban and rural areas of Vellore district, Tamil Nadu, India. GERD was defined as heartburn and regurgitation occurring at least twice per week. Associations between GERD and gender, age, anthropometric measures, and consumption of tobacco, alcohol, meat, and milk were evaluated. Odds ratios (OR) with 95% confidence intervals were derived from logistic regression models.

RESULTS

Of 6174 participants (3157 urban, 2599 male), 8.2% had GERD. The prevalence was higher in urban (11.1%) compared to rural areas (5.1%) (p < 0.001). Among patients with GERD, 34.3% used medications daily for symptom relief. On univariate analysis, GERD was associated with female gender, living in an urban area, age >30, BMI >25, and infrequent milk consumption. On multivariate analysis, female gender (OR 1.3; 95% CI 1.1-1.6), living in urban area (OR 2.3; 95% CI 1.9-2.8), age >30 years (OR 1.9; 95% CI 1.4-2.5), BMI ≥ 25 kg/m² (OR 1.3; 95% CI 1.1-1.6), and infrequent milk intake (OR 1.6; 95% CI 1.3-1.9) were independently associated with GERD.

CONCLUSION

Symptomatic GERD was found in 8.2% of respondents in this representative southern Indian community, being more prevalent in urban residents, women, older, and obese individuals.

Reduction in Gastroesophageal Reflux Disease Symptoms Is Associated with Miso Soup Intake in a Population-Based Cross-Sectional Study: The Nagahama Study

Dietary habits and lifestyles are considered to affect the frequency of epigastric symptoms. In our previous study, we found that three amino acids in Japanese broth promoted gastric emptying. We hypothesized that a higher consumption of miso soup which was mainly composed of Japanese broth and miso paste would be associated with a lower frequency of epigastric symptoms. We conducted a cross-sectional study of the association between frequency of miso soup intake and reflux or dyspepsia symptoms in a general Japanese population. Sixteen items of dietary habits were assessed using a self-reported questionnaire, and epigastric symptoms were evaluated using the Frequency Scale for Symptoms of Gastroesophageal Reflux Disease (FSSG). We fitted generalized linear models to analyze the association between miso soup intake and FSSG, reflux, or dyspepsia scores adjusted by age, sex, body mass index (BMI), another 15 dietary habits, smoking, drinking alcohol, and unfavorable dietary behaviors. A total of 9,364 subjects were included in the analysis. Trend analysis revealed that higher frequency of miso soup intake was associated with lower FSSG scores (p<0.001). In a generalized linear model, daily intake of miso soup was associated with lower FSSG, reflux, and dyspepsia scores independent of age, sex, BMI, other 15 dietary habits, smoking, drinking alcohol, and unfavorable dietary behaviors (estimate=-0.46, -0.22, and -0.27, respectively; 95% CI=-0.83, -0.12; -0.38, -0.07; and -0.47, and -0.08, respectively). Dairy intake of miso soup was associated with lower epigastric symptoms.

Gastroesophageal reflux disease symptoms in the Greek general population: prevalence and risk factors

Background and aims

Population-based data regarding the prevalence of gastroesophageal reflux disease (GERD) in Greece are very poor. This study estimated the prevalence of GERD symptoms and their risk factors in the Greek adult population.

Methods

A self-administered questionnaire was answered by a randomly selected population of 340 subjects. The question regarding “heartburn, chest pain, indigestion, or stomach acid coming up” as included in the Reflux Symptom Index was used for prevalence assessment.

Results

The monthly prevalence of GERD symptoms was found to be 52.0% in the Greek general population, with no statistically significant difference between the two sexes (P>0.05). The age group of 65–79 years showed a higher prevalence rate of GERD. Symptom severity was found to be mild (59.3%) or moderate (27.1%). The number of cigarettes smoked daily (but not smoking duration) as well as the number of alcoholic drinks consumed daily (but not the duration of alcohol drinking) were found to be related to GERD symptoms. No reported concomitant disease or medication was found to be related with GERD symptoms.

Conclusion

The prevalence of GERD symptoms in the Greek general population was found to be 52.0%. Tobacco smoking and alcohol drinking but not concomitant disease or medications were found to be related with GERD symptoms.

Gastro-esophageal reflux disease among type-2 diabetes mellitus patients in a rural area

Background: One of the most neglected complications of diabetes mellitus (DM) is gastro-esophageal reflux disease (GERD) which arises from autonomic neuropathy and diabetic gastropathy related to the extent of DM. This study was done to find prevalence of GERD in DM patients with GERD-questionnaire (GERDQ), dietary factor proportion, and their association with other GERD risk factor in rural area. Methods: This cross sectional study was conducted in Puskesmas Pelaihari from August to September 2013. Subjects with DM aged ≥ 18 were selected consecutively from both newly and previously diagnosed patients with exclusion criteria: pregnancy, in proton-pump inhibitor therapy, and had other metabolic disease(s). DM was diagnosed with ADA criteria, while GERD was diagnosed in patients with score of ≥ 8 of Indonesian GERDQ. Results: There were 30 subjects (29.7%) with GERD among 101 patients with DM and dietary factors found in GERD patients were spicy diet (90%), high-fat food (90%), irritative beverages (87%), and irritative diet (23%). Only female gender was associated with GERD vs non-GERD in DM patients (87% vs 68%, p = 0.048). Meanwhile, duration of DM (2 [0-13] vs 2 [0-19], p = 0.976), obesity (37% vs 38%, p = 0.897), age (53.2±10.5 vs 54.7 ± 9.3, p = 0.481), and uncontrolled diabetes (90% vs 94%, p = 0.421) were not associated with the GERD among DM patients.Conclusion: Prevalence of GERD in DM is somewhat high in this study. Female group with DM needs to be screened for GERD as early as possible.

Atypical symptoms and health-related quality of life of patients with asymptomatic reflux esophagitis

BACKGROUND AND AIM

Asymptomatic reflux esophagitis (RE) is simply regarded as RE without the typical reflux symptoms, but it is unknown whether patients with asymptomatic RE have atypical symptoms. The aim of this study was to examine the clinical characteristics and health-related quality of life (HRQOL) of patients with asymptomatic RE.

PATIENTS AND METHODS

Consecutive patients with RE were enrolled during January 2010 to August 2012, and of them, 41 who had taken acid-suppressing drugs were excluded, leaving 280 patients as the study group. The patients' symptoms were evaluated using a self-completed questionnaire (modified Frequency Scale for the Symptoms of gastroesophageal reflux disease [FSSG]), as well as an HRQOL questionnaire (SF-8). We defined the typical symptoms of RE as heartburn and regurgitation. Asymptomatic RE was defined if the total symptom score was 0 or the minimum (1 point) for typical reflux symptoms in the modified FSSG.

RESULTS

Of the 280 RE patients, 71.8% (n = 201) were symptomatic and 28.2% (n = 79) were asymptomatic. The atypical symptom scores were significantly lower in asymptomatic RE (2.2 ± 2.2) than in symptomatic RE patients (6.9 ± 5.2) (P < 0.0001), and the HRQOL scores were significantly higher in asymptomatic RE than in symptomatic RE (P < 0.0001). Sleep was significantly less disturbed and chronic cough less frequent in asymptomatic RE than in symptomatic RE.

CONCLUSION

Frequency and severity of atypical symptoms in patients with asymptomatic RE were significantly less than in patients with symptomatic RE, and the HRQOL score was significantly higher in those patients. These observations suggest a specific patient cohort that is truly unlikely to manifest symptoms.

The prevalence of gastroesophageal reflux disease among hospital employees

Quantitative estimate of the actual prevalence of the gastroesophageal reflux disease (GERD) is difficult to obtain because most of the patients with heartburn have intermittent symptoms. The aim of this study was to assess the frequency of typical and atypical symptoms suggesting GERD to investigate the association of habits and social conditions reported to lead to reflux in the employees of hospital. A total of 2037 collected forms were assessed. The prevalence of GERD was found to be 21.7% (442). The prevalence of symptoms other than heartburn in employees with and without GERD symptoms were 6.6% versus 3.4% (P < 0.05) for asthma, 27.6% versus 8.3% (P < 0.001) for night cough, 50% versus 19.5% (P < 0.001) for noncardiac chest pain. Dyspeptic complaints were found to be significantly higher among GERD patients (P < 0.001). By multiple logistic regression analysis, female gender (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.03-1.60, P = 0.027), non-steroidal anti-inflammatory drug medication (OR 1.29, 95% CI 1.03-1.60, P = 0.021) and body mass index over 30 (OR 2.26, 95% CI 1.60-3.18, P < 0.001) were independent risk factors associated with GERD symptoms. GERD is a common health problem in Turkey, and its prevalence is similar to that of Western populations with different symptom profiles. Female gender, non-steroidal anti-inflammatory drug, and body mass index >30 kg/m(2) were independent risk factors associated with GERD symptoms. Age, alcohol, coffee, tea, and tobacco smoking do not seem to be risk factors for reflux.

Epidemiology of gastroesophageal reflux disease

The prevalence of gastroesophageal reflux disease (GERD) symptoms increased approximately 50% until the mid-1990s, when it plateaued. The incidence of complications related to GERD including hospitalization, esophageal strictures, esophageal adenocarcinoma, and mortality also increased during that time period, but the increase in esophageal adenocarcinoma has since slowed, and the incidence of strictures has decreased since the mid-1990s. GERD is responsible for the greatest direct costs in the United States of any gastrointestinal disease, and most of those expenditures are for pharmacotherapy. Risk factors for GERD include obesity, poor diet, lack of physical activity, consumption of tobacco and alcohol, and respiratory diseases.

Epidemiology of reflux symptoms and GORD

Gastro-oesophageal reflux disease (GORD) occurs when reflux of gastric contents causes troublesome symptoms and/or complications (the Montreal definition). GORD is a common condition with a substantial economical burden to the community and it has a significant negative effect on health-related quality of life (HRQoL) while endoscopic findings like erosive oesophagitis per se seem to correlate badly with the experienced HRQoL. The prevalence of GORD varies over the world for unknown reasons, but genetic differences, difference in the Helicobacter pylori prevalence and life style factors like obesity might influence. The prevalence is lowest in East Asia (2.5-9.4%) and higher in Mid (7.6-19.4%) and Western Asia (12.5-27.6%). The highest population-based prevalence is reported from Europe (23.7%) and the US (28.8%). GORD seems to be fairly stable over time both in terms of symptoms and erosive oesophagitis, but the prevalence seems to be increasing both in Asia and in the West.

Incidence of gastroesophageal reflux disease in Uygur and Han Chinese adults in Urumqi

AIM: To investigate the incidence of gastroesophageal reflux disease (GERD) and its related risk factors in Uygur and Han Chinese adult in Urumqi, China.

METHODS: A population-based cross-sectional survey was undertaken in a total of 972 Uygur (684 male and 288 female) aged from 24 to 61 and 1023 Han Chinese (752 male and 271 female) aged from 23 to 63 years. All participants were recruited from the residents who visited hospital for health examination from November 2011 to May 2012. Each participant signed an informed consent and completed a GERD questionnaire (Gerd Q) and a lifestyle-food frequency questionnaire survey. Participants whose Gerd Q score was ≥ 8 and met one of the following requirements would be enrolled into this research: (1) being diagnosed with erosive esophagitis (EE) or Barrett’s esophagus (BE) by endoscopy; (2) negative manifestation under endoscopy (non-erosive reflux disease, NERD) with abnormal acid reflux revealed by 24-h esophageal pH monitoring; and (3) suffering from typical heartburn and regurgitation with positive result of proton pump inhibitor test.

RESULTS: According to Gerd Q scoring criteria, 340 cases of Uygur and 286 cases of Han Chinese were defined as GERD. GERD incidence in Uygur was significantly higher than in Han Chinese (35% vs 28%, χ² = 11.09, P < 0.005), Gerd Q score in Uygur was higher than in Han Chinese (7.85 ± 3.1 vs 7.15 ± 2.9, P < 0.005), and Gerd Q total score in Uygur male was higher than in female (8.15 ± 2.8 vs 6.85 ± 2.5, P < 0.005). According to normalized methods, 304 (31%) cases of Uygur were diagnosed with GERD, including 89 cases of EE, 185 cases of NERD and 30 cases of BE; 256 (25%) cases of Han Chinese were diagnosed with GERD, including 90 cases of EE, 140 cases of NERD and 26 cases of BE. GERD incidence in Uygur was significantly higher than in Han Chinese (31% vs 25%, χ² = 9.34, P < 0.005) while the incidences were higher in males of both groups than in females (26% vs 5% in Uygur, χ² = 35.95, P < 0.005, and 19.8% vs 5.2% in Han, χ² = 5.48, P < 0.025). GERD incidence in Uygur male was higher than in Han Chinese male (26% vs 19.8%, χ² = 16.51, P < 0.005), and incidence of NERD in Uygur was higher than in Han Chinese (χ² = 10.06, P < 0.005). Occupation (r = 0.623), gender (r = 0.839), smoking (r = 0.322), strong tea (r = 0.658), alcohol drinking (r = 0.696), meat-based diet (mainly meat) (r = 0.676) and body mass index (BMI) (r = 0.567) were linearly correlated with GERD in Uygur (r = 0.833, P = 0.000); while gender (r = 0.957), age (r = 0.016), occupation (r = 0.482), strong tea (r = 1.124), alcohol drinking (r = 0.558), meat diet (r = 0.591) and BMI (r = 0.246) were linearly correlated with GERD in Han Chinese (r = 0.786, P = 0.01). There was no significant difference between Gerd Q scoring and three normalized methods for the diagnosis of GERD.

CONCLUSION: GERD is highly prevalent in adult in Urumqi, especially in Uygur. Male, civil servant, smoking, strong tea, alcohol drinking, meat diet and BMI are risk factors correlated to GERD.

Identification of organic acids in wine that stimulate mechanisms of gastric acid secretion

Wine may cause stomach irritation due to its stimulatory effect on gastric acid secretion, although the mechanisms by which wine or components thereof activate pathways of gastric acid secretion are poorly understood. Gastric pH was measured with a noninvasive intragastric probe, demonstrating that administration of 125 mL of white or red wine to healthy volunteers stimulated gastric acid secretion more potently than the administration of equivalent amounts of ethanol. Between both beverages, red wine showed a clear trend for being more active in stimulating gastric acid secretion than white wine (p = 0.054). Quantification of the intracellular proton concentration in human gastric tumor cells (HGT-1), a well-established indicator of proton secretion and, in turn, stomach acid formation in vivo, confirmed the stronger effect of red wine as compared to white wine. RT-qPCR experiments on cells exposed to red wine also revealed a more pronounced effect than white wine on the fold change expression of genes associated with gastric acid secretion. Of the quantitatively abundant organic acids in wine, malic acid and succinic acid most actively stimulated proton secretion in vitro. However, addition of ethanol to individual organic acids attenuated the secretory effect of tartaric acid, but not that of the other organic acids. It was concluded that malic acid for white wine and succinic acid for red wine are key organic acids that contribute to gastric acid stimulation.

Reflux and sex: what drives testing, what drives treatment?

Gastroesophageal reflux (GER) affects ∼10-20% of American adults. Although symptoms are equally common in men and women, we hypothesized that sex influences diagnostic and therapeutic approaches in patients with GER. PubMed database between 1997 and October 2011 was searched for English language studies describing symptoms, consultative visits, endoscopic findings, use and results of ambulatory pH study, and surgical therapy for GER. Using data from Nationwide Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, we determined the sex distribution for admissions and reflux surgery between 1997 and 2008. Studies on symptoms or consultative visits did not show sex-specific differences. Even though women are less likely to have esophagitis or Barrett's esophagus, endoscopic studies enrolled as many women as men, and women were more likely to undergo ambulatory pH studies with a female predominance in studies from the US. Surgical GER treatment is more commonly performed in men. However, studies from the US showed an equal sex distribution, with Nationwide Inpatient Sample data demonstrating an increase in women who accounted for 63% of the annual fundoplications in 2008. Despite less common or severe mucosal disease, women are more likely to undergo invasive diagnostic testing. In the US, women are also more likely to undergo antireflux surgery. These results suggest that healthcare-seeking behavior and socioeconomic factors rather than the biology of disease influence the clinical approaches to reflux disease.

A substantial incidence of silent short segment endoscopically suspected esophageal metaplasia in an adult Japanese primary care practice

AIM: To determine the incidence and characteristics of endoscopically suspected esophageal metaplasia (ESEM) in a primary adult care institution.

METHODS: Eight hundred and thirty two consecutive individuals (mean age, 67.6 years) undergoing upper gastrointestinal endoscopy between January 2009 and December 2010 were included in this study. The diagnosis of ESEM was based on the criteria proposed by the Japan Esophageal Society, and was classified as long segment ESEM (3 cm or more) or short segment ESEM (< 3cm). Short segment ESEM was further divided into circumferential and partial types. Age, gender, hiatus hernia, esophagitis, gastroesophageal reflux disease (GERD)-suggested symptoms, and antacid medications were recorded as background factors. Esophagitis was graded according to the Los Angeles classification. Hiatus hernia was divided into absent and at least partially present.

RESULTS: Long and short segment ESEM were found in 0 and 184 (22.1%) patients, respectively (mean age of short segment ESEM patients, 68.3 years). Male gender and hiatus hernia were shown to be significant factors affecting short segment ESEM by both univariate (P = 0.03 and P = 9.9x10^-18) and multivariate [Odds ratio (OR) = 1.45; P = 0.04, and OR = 43.3; P = 1.5x10^-7)] analyses. Two thirds of patients with short segment ESEM did not have GERD-suggested symptoms. There was no correlation between short segment ESEM and GERD-suggested symptoms.

CONCLUSION: The incidence of short segment ESEM in our community practice seems higher than assumed in Asian countries. As GERD-suggested symptoms are a poor predictor of ESEM, endoscopists should bear in mind that silent short segment ESEM does exist and, in fact, was found in the majority of our patients.

Systematic review of the epidemiology of gastroesophageal reflux disease in Japan

BACKGROUND

Epidemiological studies of gastroesophageal reflux disease (GERD) in Japan vary in design. This systematic review examines the prevalence of GERD in Japan, distinguishing between study methodologies, and reports on changes over time and factors potentially associated with GERD.

METHODS

PubMed and Embase searches identified studies reporting the prevalence of GERD in the general population, primary care patients, and individuals undergoing routine health checks.

RESULTS

Of the twenty eligible studies, half excluded individuals taking acid-suppressive medication, so these studies would have been likely to have underestimated the prevalence by 2-3%. Nine studies reported the prevalence of at least weekly reflux symptoms (the definition closest to the Montreal definition): in seven studies this was 6.5-9.5%, but in two studies that included individuals who underwent upper gastrointestinal endoscopy the prevalence was 19.0 and 21.8%. Eight studies used symptom scores: prevalence estimates ranged from 10.2 to 29.0% in five studies using the Carlsson-Dent self-administered questionnaire (QUEST), and from 27.0 to 37.6% in three studies using the frequency scale for the symptoms of GERD. Prevalence estimates were 15.1-24.3% in three studies that reported the presence of reflux symptoms of undefined frequency. Six studies reported the prevalence of reflux esophagitis as 4.9-8.2%. Changes in prevalence over time and factors associated with reflux symptoms were inconsistent.

CONCLUSIONS

Few studies have reported the prevalence of GERD in Japan using standardized criteria. Thus, prevalence estimates vary substantially, reflecting differences in study populations and GERD definitions. However, seven studies reported that the prevalence of at least weekly symptoms was 6.5-9.5%, a finding which approaches that reported in Western populations (10-20%).

Epidemiology of gastroesophageal reflux disease in Asia: a systematic review

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.

Gastroesophageal reflux disease in Asia: A historical perspective and present challenges

Gastroesophageal reflux disease (GERD), previously uncommon in Asia, has now become an important disease in the region. Although much variability exists between studies, most endoscopy-based studies show a prevalence of erosive esophagitis of more than 10%. Symptom-based studies also show a prevalence of 6-10%. Two longitudinal follow-up studies on GERD symptoms have shown an increase with time, and several endoscopy-based time trend studies have also shown a significant increase in erosive reflux esophagitis. Studies on Barrett's esophagus have been confounded by the description of short (SSBE) and long segment (LSBE) Barrett's esophagus. Great variation in prevalence rates has been reported. SSBE vary from 0.1% to more than 20% while LSBE vary from 1-2%. Of the putative causative factors, obesity has been the most important. Many studies have linked GERD-esophagitis as well as occurrence of reflux symptoms with an increase in body mass index (BMI), obesity, especially visceral or central obesity, and metabolic syndrome. A decline in Helicobacter pylori infection with growing affluence in Asia has been broadly thought to result in healthier stomachs and a higher gastric acid output resulting in reflux disease. However, variable results have been obtained from association and H. pylori eradication studies.

Interstitial cells of Cajal, the Maestro in health and disease

Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very significant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future breakthrough in the pharmacological interventions to restore normal motor function of GI tract. This mini review describes what is known about the physiologic function and role of ICCs in GI system motility and in a variety of GI system motility disorders.

Epidemiology and clinical characteristics of GERD in the Japanese population

We reviewed articles on the epidemiology and clinical characteristics of gastroesophageal reflux disease (GERD) in Japan to clarify these features of GERD in this country. Although the definition of GERD depends on the individual study, the prevalence of GERD has been increasing since the end of the 1990s. The reasons for the increase in the prevalence of GERD may be due to increases in gastric acid secretion, a decrease in the Helicobacter pylori infection rate, more attention being paid to GERD, and advances in the concept of GERD. More than half of GERD patients had non-erosive reflux disease, and the majority (87%) of erosive esophagitis was mild type, such as Los Angeles classification grade A and grade B. There were several identified risk factors, such as older age, obesity, and hiatal hernia. In particular, mild gastric atrophy and absence of H. pylori infection influence the characteristics of GERD in the Japanese population. We also discuss GERD in the elderly; asymptomatic GERD; the natural history of GERD; and associations between GERD and peptic ulcer disease and H. pylori eradication. We examined the prevalence of GERD in patients with specific diseases, and found a higher prevalence of GERD, compared with that in the general population, in patients with diabetes mellitus, those with obstructive sleep apnea syndrome, and those with bronchial asthma. We provide a comprehensive review of GERD in the Japanese population and raise several clinical issues.

Effects of half-solid nutrients on gastroesophageal reflux in beagle dogs with or without cardioplasty and intrathoracic cardiopexy

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) has become an important modality to provide enteral access for long-term nutritional support. Nevertheless, aspiration of liquid nutrients due to vomiting and reflux esophagitis caused by gastroesophageal reflux (GER) is a significant problem associated with tube feeding by PEG.

MATERIALS AND METHODS

First, gastrostomy as an access for enteral nutrition and esophagostomy for gastroesophageal pH and Bilitec monitoring were performed in eight beagle dogs, in which the influence of viscosity of an enteral formula on the degree of GER was investigated using a commercially available liquid meal and a nearly isocaloric half-solid diet that was prepared by adding a solution mixed with dextrin, pectin, and calcium lactate. Second, similar studies were accomplished in seven beagle dogs that underwent cardioplasty and intrathoracic cardiopexy (a model of GER disease [GERD]).

RESULTS

There was no difference in the degree of GER evaluated by Bilitec monitoring between liquid and half-solid nutrients in eight normal dogs, whereas solidifying nutrients significantly reduced the frequency of reflux during the feeding periods (P=0.0180) and post-feeding periods (P=0.0277) in a model of GERD.

CONCLUSION

The use of half-solid nutrients for enteral feeding reduced the frequency of reflux in a dog model of GERD.

CYP2C19 genotype is associated with symptomatic recurrence of GERD during maintenance therapy with low-dose lansoprazole

BACKGROUND/AIMS

Maintenance therapy of gastroesophageal reflux disease (GERD) is usually performed with a low dose of a proton-pump inhibitor (PPI). Because PPIs are metabolized by CYP2C19 in the liver, we investigated whether a patient's CYP2C19 genotype was associated with symptomatic recurrence of GERD during maintenance therapy with a low dose of a PPI.

METHODS

We enrolled 124 patients with erosive GERD whose esophageal mucosal breaks were endoscopically proven to be cured after treatment with lansoprazole 30 mg/day for 8 weeks. When reflux symptoms occurred less than once per week, the dose of lansoprazole was decreased to 15 mg/day, but if symptoms then occurred more than once per week, it was restored to 30 mg/day. CYP2C19 genotypes were classified as rapid metabolizer (RM), intermediate metabolizer (IM) or poor metabolizer (PM).

RESULTS

In 18 of 54 RMs, 28 of 56 IMs, and 8 of 14 PMs, the maintenance dose of lansoprazole was decreased to 15 mg/day, but in 16 (88.9%), 22 (78.6%), and 4 (50%), respectively, there was symptomatic recurrence of GERD and the dose was restored to 30 mg/day. The hazard ratios of symptomatic recurrence of GERD in IMs and PMs compared with RMs were 0.40 (95%CI: 0.19-0.87, P = 0.021) and 0.19 (95%CI: 0.05-0.69, P = 0.011).

CONCLUSION

When the dose of lansoprazole is decreased, the RM genotype of CYP2C19 appears to be a risk factor for symptomatic recurrence of GERD. The CYP2C19 genotyping test would be useful for determining the optimal dose of a PPI for maintenance therapy of GERD.

Gastroesophageal reflux disease: an Asian perspective

The prevalence of gastroesophageal reflux disease (GERD) ranges from 2.5% to 7.1% in most population-based studies in Asia. There is evidence that GERD and its complications are rising, coinciding with a decline in Helicobacter pylori (H. pylori) infection. Asian GERD patients share similar risk factors and pathophysiological mechanisms with their Western counterparts. Possible causes for the lower prevalence of GERD include less obesity and hiatus hernia, a lesser degree of esophageal dysmotility, a high prevalence of virulent strains of H. pylori, and low awareness. Owing to the lack of precise translation for 'heartburn' in most Asian languages, reflux symptoms are often overlooked or misinterpreted as dyspepsia or chest pain. Furthermore, a symptom-based diagnosis with a therapeutic trial of the proton pump inhibitor (PPI) may be hampered by the high prevalence of H. pylori-related disease. The risk stratification for prompt endoscopy, use of a locally-validated, diagnostic symptom questionnaire, and response to H. pylori'test and treat' help improve the accuracy of the PPI test for diagnoses. PPI remain the gold standard treatment, and 'on-demand' PPI have been shown to be a cost-effective, long-term treatment. The clinical course of GERD is benign in most patients in Asia. The risk of progression from non-erosive reflux disease to erosive esophagitis is low, and treatment response to a conventional dose of PPI is generally higher. Although H. pylori eradication may lead to more resilient GERD in a subset of patients, the benefits of H. pylori eradication outweigh the risks, especially in Asian populations with a high incidence of gastric cancer.