Table 2. Identified studies that were excluded.

< Supplementary online material>

# / Reference / Reason for exclusion / Full text checked
1 / Fujiwara et al1 / Questionnaire was sent to physicians, mostly gastroenterologists – gave prevalence of GERD in patients they were treating / Yes
2 / Yamagishi et al2 / Questionnaire was given to a subset of individuals that attended for routine gastric cancer screening and from the X-rays were suspected of having gastric cancer / Yes
3 / Sakaguchi et al3 / Selected population of those who underwent endoscopy for GI symptoms / Yes
4 / Kusano et al4 / Patients undergoing endoscopy for any disease / Yes
5 / Kusano et al5 / Outpatients / Yes
6 / Okamoto et al6 / Mixture of outpatients with non-GI conditions, patients attending secondary examination from a primary GI survey or individuals having routine health checks / Yes
7 / Tanimura et al7 / Patients with chest pain / No
8 / Shimazu et al8 / Outpatients without severe complications having endoscopy / Yes
9 / Fujimoto et al9 / Mixture of outpatients who were not receiving medication for GI disease and individuals having routine checks / Yes
10 / Furukawa et al10 / Mixture of outpatients with non-GI conditions and individuals having routine checks / Yes
11 / Ohara et al11 / Outpatients / Yes
12 / Yasukochi et al12 / Outpatients and strong inclusion bias / Yes
13 / Kawano et al13 / Outpatients / Yes
14 / Kusano et al14 / Outpatients / Yes
15 / Egi et al15 / Patients with dyspepsia / Yes
16 / Okita et al16 / Majority of individuals were having routine health checks but some of the sample were having endoscopy because of clinical symptoms e.g. dyspepsia / Yes
17 / Segawa et al17 / Unselected population but only the prevalence of reflux esophagitis reported with associated factors / Yes
18 / Iwamoto et al18 / Individuals visiting clinic for routine screening and patients attending clinic with GI symptoms – the results are not separated by symptomatic/asymptomatic (confirmed with the corresponding author as the population was not clear from the article) / Yes
19 / Fujiwara et al19 / GERD patients / Yes
20 / Furuta et al20 / Article checked and found not to concern the epidemiology of GERD but a questionnaire-based search on the reasons for clinic visit / Yes
21 / Fujimoto et al21 / Article checked and found to be a review / Yes
22 / Shida et al22 / Article checked and found to be a review / Yes
23 / Tokuda et al23 / Included children / Yes

GERD, gastroesophageal reflux disease; GI, gastrointestinal.

References

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2. Yamagishi H, Koike T, Ohara S, Kobayashi S, Ariizumi K, Abe Y et al. Tongue-like Barrett's esophagus is associated with gastroesophageal reflux disease. World J Gastroenterol 2008;14:4196–203.

3. Sakaguchi M, Oka H, Hashimoto T, Asakuma Y, Takao M, Gon G et al. Obesity as a risk factor for GERD in Japan. J Gastroenterol 2008;43:57–62.

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6. Okamoto K, Iwakiri R, Mori M, Hara M, Oda K, Danjo A et al. Clinical symptoms in endoscopic reflux esophagitis: evaluation in 8031 adult subjects. Dig Dis Sci 2003;48:2237–41.

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14. Kusano M, Kouzu T, Kawano T, Ohara S. The prevalence of hiatus hernia in the Japanese. Gastroenterol Endosc 2005;47:962–73.

15. Egi Y, Kim S, Ito M, Tanaka S, Yoshihara M, Haruma K et al. Helicobacter pylori infection is the major risk factor for gastric inflammation in the cardia. Dig Dis Sci 2006;51:1582–88.

16. Okita K, Amano Y, Takahashi Y, Mishima Y, Moriyama N, Ishimura N et al. Barrett's esophagus in Japanese patients: its prevalence, form, and elongation. J Gastroenterol 2008;43:928–34.

17. Segawa K, Arisawa T, Niwa Y, Kato T, Goto H, Yoshikane H et al. A study of reflux esophagitis in an apparently healthy population. Dig Endosc 1993;5:62–66.

18. Iwamoto M, Kato K, Mizuno S, Miyamoto S, Takeuchi R, Iwasaki A et al. Evaluation of gastro-oesophageal flap valve is useful for diagnosing gastro-oesophageal reflux disease. Aliment Pharmacol Ther Symposium Series 2006;2:141–46.

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20. Furuta K, Adachi K, Arima N, Tanaka S, Miki M, Azumi T et al. Study on the recognition of upper abdominal symptoms by Japanese adults. Nippon Shokakibyo Gakkai Zasshi 2008;105:817–24.

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22. Shida K, Hoshihara Y. Epidemiology of reflux esophagitis. Nippon Rinsho 2002;60 Suppl 1:135–43.

23. Tokuda Y, Takahashi O, Ohde S, Shakudo M, Yanai H, Shimbo T et al. Gastrointestinal symptoms in a Japanese population: a health diary study. World J Gastroenterol 2007;13:572–78.