You are here

  • Home
  • Archive
  • Volume 66, Issue 6
  • The global prevalence of IBS in adults remains elusive due to the heterogeneity of studies: a Rome Foundation working team literature review

Article Text

Article menu

Download PDFPDF

Neurogastroenterology
Original article
The global prevalence of IBS in adults remains elusive due to the heterogeneity of studies: a Rome Foundation working team literature review
  1. Ami D Sperber1,
  2. Dan Dumitrascu2,
  3. Shin Fukudo3,
  4. Charles Gerson4,
  5. Uday C Ghoshal5,
  6. Kok Ann Gwee6,
  7. A Pali S Hungin7,
  8. Jin-Yong Kang8,
  9. Chen Minhu9,
  10. Max Schmulson10,
  11. Arkady Bolotin1,
  12. Michael Friger1,
  13. Tamar Freud1,
  14. William Whitehead11
  1. 1Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
  2. 22nd Medical Department of Internal Medicine, University of Medicine and Pharmacy, Cluj-Napoca, Romania
  3. 3Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, Seiryo Aoba, Japan
  4. 4Division of Gastroenterology, Mt. Sinai School of Medicine, Mind-Body Digestive Center, New York, New York, USA
  5. 5Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGI), Lucknow, India
  6. 6Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
  7. 7Durham University School of Medicine, Pharmacy and Health, Wolfson Research Institute, Stockton-on-Tees, UK
  8. 8Department of Gastroenterology, St. George's Hospital, London, UK
  9. 9Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
  10. 10Laboratory of Liver, Pancreas and Motility (HIPAM), Unit of Research in Experimental Medicine, Faculty of Medicine, Universidad Nacional Autonoma de Mexico (UNAM), Hospital General de México, Mexico City, Mexico
  11. 11Center for Functional GI & Motility Disorders, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
  1. Correspondence to Professor Ami D Sperber, Emeritus Professor of Medicine, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel; amiroie{at}me.com

Abstract

Objectives The global prevalence of IBS is difficult to ascertain, particularly in light of the heterogeneity of published epidemiological studies. The aim was to conduct a literature review, by experts from around the world, of community-based studies on IBS prevalence.

Design Searches were conducted using predetermined search terms and eligibility criteria, including papers in all languages. Pooled prevalence rates were calculated by combining separate population survey prevalence estimates to generate an overall combined meta-prevalence estimate. The heterogeneity of studies was assessed.

Results 1451 papers were returned and 83, including 288 103 participants in 41 countries, met inclusion criteria. The mean prevalence among individual countries ranged from 1.1% in France and Iran to 35.5% in Mexico. There was significant variance in pooled regional prevalence rates ranging from 17.5% (95% CI 16.9% to 18.2%) in Latin America, 9.6% (9.5% to 9.8%) in Asia, 7.1% (8.0% to 8.3%) in North America/Europe/Australia/New Zealand, to 5.8% (5.6% to 6.0%) in the Middle East and Africa. There was a significant degree of heterogeneity with the percentage of residual variation due to heterogeneity at 99.9%.

Conclusions The main finding is the extent of methodological variance in the studies reviewed and the degree of heterogeneity among them. Based on this, we concluded that publication of a single pooled global prevalence rate, which is easily calculated, would not be appropriate or contributory. Furthermore, we believe that future studies should focus on regional and cross-cultural differences that are more likely to shed light on pathophysiology.

  • IRRITABLE BOWEL SYNDROME
  • FUNCTIONAL BOWEL DISORDER
  • EPIDEMIOLOGY

https://doi.org/10.1136/gutjnl-2015-311240

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Significance of this study

    What is already known on this subject?

    • The prevalence of IBS has been studied extensively.

    • The methodology used to study IBS prevalence is not uniform among studies.

    • Estimates of IBS prevalence usually are reported in the range of 10–20%, but the basis for these estimates is not clear.

    What are the new findings?

    • This literature review of IBS prevalence in population-based studies was conducted by a multinational group of investigators, who had facilitated access to articles published in multiple languages because of their familiarity with regional publications and languages.

    • The main finding of the study is the extent of methodological variance in the studies and the significant degree of heterogeneity among them.

    • There is a noteworthy lack of data from Africa, Eastern Europe and Arab countries.

    • The predominance of women who fulfil the different diagnostic criteria for IBS is reaffirmed in this study.

    How might it impact on clinical practice in the foreseeable future?

    • The assessment of prevalence rates is important for understanding the distribution and burden of disease, for the evaluation of treatment modalities, to provide incentive for the development of new drugs and for the allocation of healthcare resources and research funding.

    • The lack of reliable prevalence data is a barrier to attaining these goals.

    • The results of the study highlight the need for a global survey of IBS prevalence with multinational collaboration and uniform research methodology. Future studies should focus on regional and cross-cultural differences that are more likely to shed light on pathophysiology.

    Introduction

    The prevalence of IBS, a common functional GI disorder (FGID), has been studied extensively. Multiple methodologies have been used to assess the prevalence of IBS around the world. It has been investigated in convenience samples among workers or students or during health surveys1 and in urban neighbourhoods and rural areas.2–4 Some studies have been hospital based or clinic based,5 while others were community based. In addition, the methods of data collection have included in-person household interview, mail survey, telephone survey and, recently, internet survey. Finally, different diagnostic criteria have been used in these studies including the Manning criteria (in different studies either two, three or four of the six original Manning criteria were used to diagnose IBS), Rome I–III and others.6–9

    Determining population prevalence by self-reported symptoms through a questionnaire, in the absence of an established diagnostic biomarker, could lead to an inaccurate estimation of the actual population prevalence rate. There are differences in symptom interpretation and reporting patterns among different countries, geographical regions, and cultural and ethnic groups.10 ,11 Even if the survey methodology was uniform, there might be cultural and regional differences in perception, for example, relating to pain, bloating, bowel habit and other symptoms. Thus, gaining a global perspective on the prevalence of IBS remains difficult because of methodological heterogeneity and cultural differences in symptom perception and reporting. Potential confounders in multinational comparative prevalence studies for IBS are shown in box 1. These issues are presented and discussed succinctly by Quigley et al.12

    Box 1

    Potential sources of methodological confounding in multinational comparative IBS prevalence studies

    1. Variations in diagnostic criteria

      1. Manning (using two, three or four out of the six criteria)

      2. Rome I, II, III

    2. Study population

      1. Age, gender, class

      2. Culture, ethnic group, language

      3. Select group versus representative of general population

        1. Clinic-based

        2. Students, workers, urban versus rural, etc.

    3. Survey instrument

      1. Questionnaire

      2. Validation of translated questionnaires

    4. Survey method

      1. Mail

      2. Personal interview

      3. Telephone

      4. Self-administered questionnaire

      5. Internet

    5. Cultural and regional differences in symptom interpretation and reporting.

    Lovell and Ford reported the results of a systematic review of IBS prevalence.13 The authors found a pooled global prevalence of 11.2% (95% CI 9.8% to 12.8%), with a range among countries from 1.1% to 45.0%.

    The purpose of the present study was to conduct a literature review of publications reporting the epidemiology and prevalence of IBS in community-based studies in as many languages as possible. A team of experts in the field who represent all regions of the world and are fluent in multiple languages conducted the review.

    Methods

    The Rome Foundation commissioned a Working Team on Cross-cultural, Multinational Research in the FGIDs to address the issues and challenges related to global research in the FGIDs.10 ,14 The full report of the working team can be downloaded at http://theromefoundation.org/committees/multinational_com.cfm, and an article summarising the full report was published.15 One of the working team's mandates was to conduct a review of IBS global epidemiology. The review was conducted by working team members representing different geographical areas, each responsible for using the study protocol and search parameters to identify all relevant studies in their assigned region. Searched databases were Medline, Embase, Web of Science, Cochrane, Latindex, Bireme, SciELO and other databases including recent abstracts, compilations and meeting procedures. In cases where there were other studies cited in the paper that were not identified in the search, they were reviewed for eligibility. In addition, there were no language restrictions and the investigators were encouraged to survey publications in as many languages as they could, getting help from colleagues in their regions to translate when required. The regions covered and the responsible investigators are shown in table 1.

    View this table:
    Table 1

    Delegation of responsibility for regional literature searches

    Search terms and eligibility criteria

    The medical literature was searched using the following sequence of terms: IBS OR irritable bowel syndrome OR functional bowel disorder AND epidemiology OR prevalence AND region OR country (eg, Latin America OR Mexico OR Guatemala OR Colombia OR Argentina et al).

    Papers and abstracts that were identified by the search terms were considered to be eligible for the study and were included in the analyses in accordance with the criteria shown in table 2. The present paper relates only to the subgroup of studies that were conducted in the general population or were community based. Thus, the full study database of extracted articles is larger than the selected database used in the present analysis because it also contains studies that are not of general or community-based populations.

    View this table:
    Table 2

    Eligibility criteria for the present report

    Study database and data extraction

    Each investigator completed the database for their region and then the individual databases were merged into the final study database. The data that were extracted from all papers included the following variables (if cited in the paper): type of paper and year of publication (eg, journal articles published in 1999 and later, abstracts published from 2006 to 2013); country; language of study; study design (eg, cross-sectional); study setting (eg, urban community); survey instrument (eg, Rome II questionnaire); method of data collection (eg, in-person interview, mail survey, telephone survey), number of participants; females (%); response rate (%); mean age; mean years of education; whether the study was multinational/cross-cultural; IBS prevalence (%); IBS prevalence by gender; IBS-constipation (IBS-C) (%); IBS-diarrhoea (IBS-D) (%); IBS-mixed (%); and IBS-unclassified (%). The earliest year of publication was chosen as 1999, the year that the Rome II diagnostic criteria were developed, based on our perception that epidemiological research in the FGIDs became more rigorous at this time and that, in general, earlier research was less methodologically sound than studies that began around 1999–2000.

    The representative for each region selected all papers from their region that were included in the final analyses, in many cases with research assistants. All papers were also read and reviewed by the first author (ADS). In cases where the appropriateness of the study was questioned by ADS, an email exchange with the regional representative was conducted to clarify the issues raised. Where necessary, the first author of the paper was consulted for clarification. The final decision on inclusion was reached by agreement between ADS and the regional representative, and, in some cases, papers were excluded from the study based on this joint review.

    Statistical analyses

    Descriptive analyses were performed using the SPSS software package (V.21, Chicago, Illinois, USA). Descriptive statistics are presented as percentages for categorical variables and means (SD) for continuous variables.

    To calculate pooled prevalence rates, we used the appropriate method, as published by Yang,16 which combines separate population survey prevalence estimates into an overall meta-prevalence estimate. For the purpose of pooled analyses, the countries were grouped into (a) Asia, (b) North America/Europe/Australia/New Zealand, (c) Latin America and (d) the Middle East and Africa. For further analysis of the data, we used the Stata software (V.13.1, Stata Corp., Texas, USA). We performed a univariate meta-analysis, in which each group of countries contributes an estimate of a single quantity (eg, IBS, gender), and multivariate meta-analysis, in which groups of countries (geographic regions) contribute estimates of more than one quantity: for example, IBS subgroup by geographic region.

    Then, we modelled the effects across regions using consistency and inconsistency models. To analyse variables of interest, we used the univariate random-effects meta-regression model because, compared with a fixed-effect model, it assigns more moderate weights to each study, that is, more weight to small studies and less to large ones. As a result, the CI about each coefficient (and slope) is wider than in the fixed-effect model and the p values corresponding to each coefficient and to the model as a whole are less likely to meet the criterion for statistical significance. This added a negative bias, making statistically significant comparisons more robust.

    For the heterogeneity statistic, the weighted sum of squares of the residuals was used as a generalisation of Cochran's Q from meta-analysis to meta-regression. Following this, a test of the null hypothesis of no residual (unexplained) heterogeneity was obtained by comparing Cochran's Q to a χ2 distribution.17 ,18

    Results

    Studies included in the paper

    In all, 1451 papers were returned by the search (figure 1). Of these, 162 met the inclusion criteria and the remaining 1289 were disqualified for the following reasons: non-epidemiological or non-IBS study—737; review—236; duplicate (more than one report for same study)—240; earlier than 1999 for article—33; earlier than 2006 for abstract—4; inappropriate population age—23; inappropriate study design—15; and study population less than 100—1.

    Figure 1
    Figure 1

    Flow diagram of citations retrieved by the literature search and included in the present study.

    Of the 162 publications that met the review criteria, 83 were included in the present report.2 ,6 ,9 ,19–98 The other 79 were disqualified after further review because they were not population or community based or they were repeat publications of the same data. Of the 83 studies included in this review, 41 were published in the English-language literature. The others were distributed as follows: Spanish—16; Chinese—13; Persian—3; Turkish—2; Arabic, Dutch, Finnish, Greek, Hebrew, Icelandic, Norwegian and Portuguese—1 each.

    The final 83 studies included 288 103 participants in 41 countries (the largest study encompassed eight countries). The mean number of participants per study was 3471.1, and the median sample size was 1624.0. The largest numbers of studies, by country, were from China (N=8), Japan (N=6), and South Korea and Mexico (N=5 each). The mean pooled response rate, reported in 62 studies, was 71.3% (95% CI 71.1 to 71.4). The response rates by region were 89.0% in Asia (N=19), 85.3% in Latin America (N=16), 76.5% in the Middle East and Africa (N=11) and 54.0% in North America/ Europe/Australia/New Zealand (N=19).

    In 77 papers (92.8%), the authors reported the method of data collection including personal interview (N=40 (51.9%)), mail (N=16 (20.8%)) and telephone (N=9 (11.7%)). Personal interviews were the method of data collection in 16 of 21 studies from Asia (76.2%), 9 of 12 studies (75%) from the Middle East, 9 of 12 studies (75%) from Africa, and 8 of 14 studies (57.1%) from Latin America. Personal interviews were less commonly employed in North America/ Europe/Australia/New Zealand (7 of 23, 30.4%) with more studies using mailed questionnaires (13 of 23, 56.0%) and some using telephone interviews (3 of 23, 13.0%). IBS prevalence by survey method was 6.8% by personal interview, 10.5% by mail questionnaire and 8.0% by telephone interview for all regions taken together.

    Diagnostic criteria

    Twelve studies used the Manning criteria (7 as a single criterion), 12 used Rome I (7 as a single criterion), 38 Rome II (36 as a single criterion), 14 Rome III (12 as a single criterion) and 7 used other criteria. IBS prevalence by diagnostic criteria was 7.8% by Rome II (N=38), 8.3% by Manning criteria, 6.7% by Rome I, 9.1% by Rome III and 12.8% in studies in which the diagnostic criterion was not specified. Table 3 presents regional IBS prevalence rates by method of data collection and diagnostic criteria.

    View this table:
    Table 3

    Comparison of regional pooled prevalence rates (%) for IBS by sex, survey method and diagnostic criteria

    Sociodemographic variables

    Of the 288 103 participants, 55.0% (95% CI 46.2% to 69.4%) were females (N=74 studies) with a range from 28%96 to 74.3%.31 The mean age was 40.0 (95% CI 31.2 to 51.0) years with a range from 27.7 years (Vietnam)51 to 53.0 years (Germany).57

    Prevalence rates

    Individual study rates

    The 83 studies were conducted in 41 countries. The mean IBS prevalence by country ranged from 3.3% in France (N=3 studies) to 31.6% in Nigeria (N=1 study). There was a significant difference in the mean prevalence among countries (p<0.0001). The prevalence, in individual studies, ranged from 1.1% in France71 and Iran94 to 35.5% in Mexico.97 Different studies from the same country yielded, in some cases, a broad range of results. For example, in the five studies included in this paper from Mexico, the prevalence rates were 4.4%,86 16.0%,84 16.9%,81 28.9%85 and 35.5%.97

    Forty-two studies reported prevalence rates for IBS subgroups (IBS-D, IBC-C, etc). There was a difference in the prevalence of IBS-C among the regions, ranging from 12.7% for Asia, 13.6% for North America/Western Europe/Australia/New Zealand, 39.4% for Latin America, to 43.3% for the Middle East. The data were not sufficient to make other analyses of IBS by subtype.

    Pooled rates

    Table 4 shows the pooled prevalence rate for IBS per region. Pooled prevalence rates were higher in women than men (10.2% vs 8.8%), and prevalence rates were also higher in women than men in each region separately (table 4).

    View this table:
    Table 4

    IBS prevalence, gender and age by geographical region

    The highest prevalence rate was found in Latin America at 17.5% (95% CI 16.9% to 18.2%). Although there were many studies conducted in Latin America (N=17, 20.5% of all studies), the total number of participants in that region was low (N=12 805, 4.4% of all subjects). Thus, the studies in that region had substantially lower sample sizes than other regions of the world, with a mean in Latin America of 753, compared with 4491 for North America, Western Europe, Australia/New Zealand, 3999 for Asia and 3844 for the Middle East.

    There was a statistically significant degree of heterogeneity among the geographical regions, using North America/Europe/Australia/New Zealand (table 5) as the reference region and confirmed using Latin America as the reference group (not shown) in two separate runs. The results of the univariate random-effects meta-regression for IBS by region appear in table 5.

    View this table:
    Table 5

    Univariate random-effects meta-regression for IBS, by region with North America/Europe/Australia/New Zealand as the reference group

    Discussion

    We conducted a review of IBS prevalence in 83 general population or community-based studies conducted around the world and reported in multiple languages. We believe that the most significant finding of the present study is the extent of methodological variance in the included studies and the statistically significant degree of heterogeneity among them, not the calculated pooled global IBS prevalence or even the prevalence by geographical region. This result should not be surprising in light of the variation in sample size, setting, diagnostic criteria, method of data collection and overall research methodology.99 In fact, our results show very heterogeneous results when comparing IBS prevalence rates by regions and potential confounding factor, for example, method of data collection and diagnostic criteria used (table 4).

    Compounding these factors are potential cultural differences in the reporting and interpretation of symptoms15 and the effect of inappropriate translation of study questionnaires.100 ,101

    In this respect, our results are compatible with those reported by Lovell and Ford13 since they also found significant heterogeneity between studies in all of their statistical analyses, although they placed less emphasis on this finding. The review by Lovell and Ford included 80 articles, while the present study includes 83. Thus, the question might arise as to why the present study did not contain a much larger number of papers since it has more foreign language articles and could include articles published after the Lovell and Ford paper. We believe that there are several explanations for this outcome: (a) the time frame for the Lovell and Ford review was 1947–2011, while the time frame for the present study was much shorter from 1999 to 2013; (b) the Lovell and Ford review included studies with subjects from the age of 15 and above while the present one included studies with subjects from the age of 18 and above; and (c) the lower limit for the number of study subjects in the Lovell and Ford review was 50, while the lower limit in the present study was 100.

    Prevalence rates are important for multiple reasons including (a) for epidemiologists and health economists—the distribution and burden of disease; (b) for clinicians—commonality of disease, probability of diagnosis and evaluation of treatment modalities; (c) for the pharmaceutical industry and regulators—incentive to develop new drugs; (d) for health policymakers—allocation of healthcare resources and research funding; (e) for clinicians, epidemiologists, medical anthropologists, etc—cross-cultural comparisons; and (f) for all—the satisfaction of intellectual and scientific curiosity.

    There is a noteworthy lack of data from certain areas of the world. The African continent is almost completely unrepresented, and most studies conducted there5 ,102 were on select populations, which disqualified them from inclusion in the present review. Other regions that were seriously under-represented are Eastern Europe and the Arab world. Surprisingly, there were only two studies31 ,32 from the USA and Canada that were considered to meet the study inclusion criteria. We believe this is a consequence of a shift in emphasis from overall prevalence of IBS in the population to the association of IBS diagnosis with other characteristics such as age, race, ethnicity and socioeconomic status. Also, the absence of a centralised healthcare system could limit epidemiological studies in the USA.

    Despite the heterogeneity of results, which makes it difficult to assess the global prevalence of IBS, it is clearly a prevalent disorder. The Lovell and Ford review is a landmark report on global IBS prevalence. Nevertheless, we believe that the results of the present study had an advantage in that it accessed more bibliographic depositories including languages other than English and had a large group of expert investigators who reviewed the literature in their own regions with expert translation at hand when needed. In fact, judging by its list of references, the Lovell and Ford study had less than half the number of articles that were published in a language other than English, compared with the present study, particularly in Spanish and Chinese. One of their conclusions was that there is a scant amount of published data from Central America (eg, Mexico). We have included several relevant studies from that region. Thus, the two reviews can be viewed as complementary, and similar conclusions can be drawn from them, especially relating to the heterogeneity of methodologies used in epidemiological studies of IBS, with the inherent implications for the interpretation of prevalence comparisons.

    Another finding that is consistent throughout the studies is the predominance of females. Some individual studies, for example, from India, have shown higher rates among men than women. These studies are usually from a clinical setting and may reflect higher consulter rates among men than women in certain cultures.103–105 Although the prevalence of IBS among men is lower than women, it is still high in absolute terms, justifying and even mandating the inclusion of men in clinical trials.

    The main strengths of this study include the rigorous design and search parameters, the exclusion of non-population-based and non-community studies, the composition of the expert team that reviewed all the papers by region, and the inclusion of many non-English-language papers, articles published in journals not included in major repositories and recent abstracts. The meta-regression analysis assured a pooled prevalence that combines separate population survey prevalence estimates to generate an overall combined estimate. The results of the heterogeneity analyses made it clear that we cannot infer that the overall pooled prevalence is a reliable statistic. Thus, the heterogeneity of the results precludes firm conclusions as to the global prevalence of IBS. However, we do not regard this as a study limitation; rather, it is a clear outcome of the study, which can drive future research.

    A potential limitation of this study is that we did not have a formal requirement that the data search and extraction be conducted in duplicate. However, there were several safeguards in place. No article was accepted as eligible for review unless both the regional PI and the study PI (ADS) approved it. As mentioned above, in all cases of doubt the paper's eligibility was determined by joint review and, in some cases, papers originally considered eligible for the study were rejected. In addition, although duplicate searches were not mandated, in practice in most regions there was more than one investigator who determined the eligibility of the papers that they extracted and this was followed by the overall review of eligibility by the first author.

    Other potential limitations include insufficient or absent data from some areas of the world. Again, since this reflects the actual situation it is less a limitation than an outcome of the study. The allocation of regions for data analyses could be somewhat problematic in that some regions may be more heterogeneous than others. An alternative approach that might reduce heterogeneity could be to assess IBS prevalence in pooled studies by diagnostic criteria or method of data collection, which we did in secondary analyses. However, many papers used more than one diagnostic criterion in the same study and some did not use the more established criteria at all, so this approach also has inherent difficulties. Another strategy could be to define smaller geographical regions, for example, to divide Asia and/or Latin America into smaller, more homogeneous subregions. However, the number of regions for analysis would increase and the number for each region would become small, in some cases to the point of obviating useful analyses. Decisions of this type always entail a trade-off, and the final decision is always likely to engender criticism.

    In conclusion, given current methodological limitations, the goal of ascertaining a globally representative prevalence rate for IBS is likely to elude researchers for some time. However, this might actually be less important than determining reliable regional estimates of IBS prevalence and comparing these differences among regions in terms of variables such as diet, exposure to pathogens, healthcare practices, psychological variables, and prevailing cultural and religious beliefs. Studies with this more limited goal may advance our understanding of the pathophysiology of IBS and improve its medical management more effectively than a global estimate of IBS prevalence.

    Acknowledgments

    The authors would like to acknowledge the contribution of Drs Eamonn Quigley and Enrico Corazziari, who reviewed the draft manuscript and suggested important revisions.

    References

    1. ↵
      1. Tan YM,
      2. Goh KL,
      3. Muhidayah R, et al
      . Prevalence of irritable bowel syndrome in young adult Malaysians: a survey among medical students. J Gastroenterol Hepatol 2003;18:1412–16. doi:10.1046/j.1440-1746.2003.03212.x
      OpenUrlCrossRefPubMed
    2. ↵
      1. Masud MA,
      2. Hasan M,
      3. Azad Khan AK
      . Irritable bowel syndrome in a rural community in Bangladesh: prevalence, symptoms pattern, and health care seeking behavior. Am J Gastroenterol 2001;96:1547–52. doi:10.1111/j.1572-0241.2001.03760.x
      OpenUrlCrossRefPubMedWeb of Science
    3. ↵
      1. Danivat D,
      2. Tankeyoon M,
      3. Sriratanaban A
      . Prevalence of irritable bowel syndrome in a non-Western population. BMJ 1988;296:1710. doi:10.1136/bmj.296.6638.1710
      OpenUrlFREE Full Text
    4. ↵
      1. Bi-Zhen W,
      2. Qi-Ying P
      . Functional bowel disorders in apparently healthy Chinese people. Chin J Epid 1988;9:345–9.
      OpenUrl
    5. ↵
      1. Lule GN,
      2. Amayo EO
      . Irritable bowel syndrome in Kenyans. East Afr Med J 2002;79:360–3.
      OpenUrlPubMed
    6. ↵
      1. Mearin F,
      2. Badia X,
      3. Balboa A, et al
      . Irritable bowel syndrome prevalence varies enormously depending on the employed diagnostic criteria: comparison of Rome II versus previous criteria in a general population. Scand J Gastroenterol 2001;3:1155–61. doi:10.1080/00365520152584770
      OpenUrl
    7. ↵
      1. Sperber AD,
      2. Shvartzman P,
      3. Friger M, et al
      . A comparative reappraisal of the Rome II and Rome III diagnostic criteria: are we getting closer to the ‘true’ prevalence of irritable bowel syndrome? Eur J Gastroenterol Hepatol 2007;19:441–7. doi:10.1097/MEG.0b013e32801140e2
      OpenUrlCrossRefPubMedWeb of Science
    8. ↵
      1. Agréus L
      . Rome? Manning? Who cares? Am J Gastroenterol 2000;95:2679–81. doi:10.1111/j.1572-0241.2000.03171.x
      OpenUrlCrossRefPubMed
    9. ↵
      1. Morgan D,
      2. Martin C,
      3. Peña E, et al
      . Significant differences in Rome II and Rome III determination of FGID prevalence: Population-based assessments in Central America. Gastroenterology 2008;134(Suppl 1):A-418.
      OpenUrl
    10. ↵
      1. Sperber AD,
      2. Drossman DA,
      3. Quigley EM
      . IBS—The global perspective (a Rome Foundation-WGO symposium). Am J Gastroenterol 2012;107:1602–9. doi:10.1038/ajg.2012.106
      OpenUrlCrossRefPubMed
    11. ↵
      1. Sperber AD,
      2. Gwee K-A,
      3. Hungin AP, et al
      . Conducting Multinational, Cross-cultural Research in the Functional GI Disorders and Fostering Multinational Research Networks. Secondary Conducting Multinational, Cross-cultural Research in the Functional GI Disorders and Fostering Multinational Research Networks. 2014. http://www.romecriteria.org/committees/WorkingTeamFinalReport_Jan2014.pdf
    12. ↵
      1. Quigley EM,
      2. Abdel-Hamid H,
      3. Barbara G, et al
      . A global perspective on irritable bowel syndrome: a consensus statement of the World Gastroenterology Organisation Summit Task Force on irritable bowel syndrome. J Clin Gastroenterol 2012;46:356–66. doi:10.1097/MCG.0b013e318247157c
      OpenUrlCrossRefPubMed
    13. ↵
      1. Lovell RM,
      2. Ford AC
      . Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis. Clin Gastroenterol Hepatol 2012;10:712–21.e4. doi:10.1016/j.cgh.2012.02.029
      OpenUrlCrossRefPubMed
    14. ↵
      1. Sperber AD
      . The challenge of cross-cultural, multi-national research: potential benefits in the functional gastrointestinal disorders. Neurogastroenterol Motil 2009;21:351–60. doi:10.1111/j.1365-2982.2009.01276.x
      OpenUrlCrossRefPubMed
    15. ↵
      1. Sperber AD,
      2. Gwee KA,
      3. Hungin AP, et al
      . Conducting multinational, cross-cultural research in the functional gastrointestinal disorders: issues and recommendations. A Rome Foundation working team report. Aliment Pharmacol Ther 2014;40:1094–102. doi:10.1111/apt.12942
      OpenUrlCrossRefPubMed
    16. ↵
      1. Yang B
      . Meta Prevalence Estimates. Generating combined prevalence estimates from separate population surveys: NSW Department of Health, Center for Epidemiology and Research, 2007.
    17. ↵
      1. Higgins JP,
      2. Thompson SG
      . Controlling the risk of spurious findings from meta-regression. Stat Med 2004;23:1663–82. doi:10.1002/sim.1752
      OpenUrlCrossRefPubMedWeb of Science
    18. ↵
      1. Lipsey MW,
      2. Wilson DB
      . Practical Meta-Analysis. Thousand Oaks, CA: Sage, 2001.
    19. ↵
      1. Drug VL,
      2. Oprea L,
      3. Bunescu L, et al
      . The epidemiology of the Irritable Bowel Syndrom in urban general population. Rom J Gastroenterol 2000;9:83–6.
      OpenUrl
    20. ↵
      1. Ziółkowski BA,
      2. Pacholec A,
      3. Kudlicka M, et al
      . Prevalence of abdominal symptoms in the Polish population. Przegląd Gastroenterologiczny 2012;7:20–5.
      OpenUrl
    21. ↵
      1. Jeong JJ,
      2. Choi MG,
      3. Cho YS, et al
      . Chronic gastrointestinal symptoms and quality of life in the Korean population. World J Gastroenterol 2008;14:6388–94. doi:10.3748/wjg.14.6388
      OpenUrlCrossRefPubMed
    22. ↵
      1. Kawamura A,
      2. Adachi K,
      3. Takashima T, et al
      . Prevalence of irritable bowel syndrome and its relationship with Helicobacter pylori infection in a Japanese population. J Gastroenterol Hepatol 2001;16:384–8. doi:10.1046/j.1440-1746.2001.02454.x
      OpenUrlCrossRefPubMed
    23. ↵
      1. Miwa H
      . Prevalence of irritable bowel syndrome in Japan: Internet survey using Rome III criteria. Patient Prefer Adherence 2008;2:143–7.
      OpenUrlPubMed
    24. ↵
      1. Lee SY,
      2. Lee KJ,
      3. Kim SJ, et al
      . Prevalence and risk factors for overlaps between gastroesophageal reflux disease, dyspepsia, and irritable bowel syndrome: a population-based study. Digestion 2009;79:196–201. doi:10.1159/000211715
      OpenUrlCrossRefPubMed
    25. ↵
      1. Hongo M
      . Epidemiology of FGID symptoms in Japanese general population with reference to life style. J Gastroenterol Hepatol 2011;26(Suppl 3):19–22. doi:10.1111/j.1440-1746.2011.06632.x
      OpenUrlCrossRefPubMed
    26. ↵
      1. Park DW,
      2. Lee OY,
      3. Shim SG, et al
      . The Differences in Prevalence and Sociodemographic Characteristics of Irritable Bowel Syndrome According to Rome II and Rome III. J Neurogastroenterol Motil 2010;16:186–93. doi:10.5056/jnm.2010.16.2.186
      OpenUrlCrossRefPubMed
    27. ↵
      1. Kumano H,
      2. Kaiya H,
      3. Yoshiuchi K, et al
      . Comorbidity of irritable bowel syndrome, panic disorder, and agoraphobia in a Japanese representative sample. Am J Gastroenterol 2004;99:370–6. doi:10.1111/j.1572-0241.2004.04048.x
      OpenUrlCrossRefPubMedWeb of Science
    28. ↵
      1. Yun CH,
      2. Lee SK,
      3. Kim H, et al
      . Association between irritable bowel syndrome and restless legs syndrome in the general population. J Sleep Res 2012;21:569–76. doi:10.1111/j.1365-2869.2012.01011.x
      OpenUrlCrossRefPubMed
    29. ↵
      1. Matsuzaki J,
      2. Suzuki H,
      3. Fukushima Y, et al
      . High frequency of overlap between functional dyspepsia and overactive bladder. Neurogastroenterol Motil 2012;24:821–7. doi:10.1111/j.1365-2982.2012.01939.x
      OpenUrlCrossRefPubMed
    30. ↵
      1. Han SH,
      2. Lee OY,
      3. Bae SC, et al
      . Prevalence of irritable bowel syndrome in Korea: population-based survey using the Rome II criteria. J Gastroenterol Hepatol 2006;21:1687–92. doi:10.1111/j.1440-1746.2006.04269.x
      OpenUrlCrossRefPubMed
    31. ↵
      1. Li FX,
      2. Patten SB,
      3. Hilsden RJ, et al
      . Irritable bowel syndrome and health-related quality of life: a population-based study in Calgary, Alberta. Can J Gastroenterol 2003;17:259–63.
      OpenUrlPubMedWeb of Science
    32. ↵
      1. Locke GR III.,
      2. Zinsmeister AR,
      3. Fett SL, et al
      . Overlap of gastrointestinal symptom complexes in a US community. Neurogastroenterol Motil 2005;17:29–34. doi:10.1111/j.1365-2982.2004.00581.x
      OpenUrlCrossRefPubMedWeb of Science
    33. ↵
      1. Perveen I,
      2. Hasan M,
      3. Masud MA, et al
      . Irritable bowel syndrome in a Bangladeshi urban community: prevalence and health care seeking pattern. Saudi J Gastroenterol 2009;15:239–43. doi:10.4103/1319-3767.56099
      OpenUrlCrossRefPubMed
    34. ↵
      1. Makharia GK,
      2. Verma AK,
      3. Amarchand R, et al
      . Prevalence of irritable bowel syndrome: a community based study from northern India. J Neurogastroenterol Motil 2011;17:82–7. doi:10.5056/jnm.2011.17.1.82
      OpenUrlCrossRefPubMed
    35. ↵
      1. Shah SS,
      2. Bhatia SJ,
      3. Mistry FP
      . Epidemiology of dyspepsia in the general population in Mumbai. Indian J Gastroenterol 2001;20:103–6.
      OpenUrlPubMed
    36. ↵
      1. Husain N,
      2. Chaudhry IB,
      3. Jafri F, et al
      . A population-based study of irritable bowel syndrome in a non-Western population. Neurogastroenterol Motil 2008;20:1022–9. doi:10.1111/j.1365-2982.2008.01143.x
      OpenUrlCrossRefPubMed
    37. ↵
      1. Xiong LS,
      2. Chen MH,
      3. Chen HX, et al
      . A population-based epidemiologic study of irritable bowel syndrome in South China: stratified randomized study by cluster sampling. Aliment Pharmacol Ther 2004;19:1217–24. doi:10.1111/j.1365-2036.2004.01939.x
      OpenUrlCrossRefPubMed
    38. ↵
      1. Zhao Y,
      2. Zou D,
      3. Wang R, et al
      . Dyspepsia and irritable bowel syndrome in China: a population-based endoscopy study of prevalence and impact. Aliment Pharmacol Ther 2010;32:562–72. doi:10.1111/j.1365-2036.2010.04376.x
      OpenUrlCrossRefPubMed
    39. ↵
      1. Hu WH,
      2. Wong WM,
      3. Lam CL, et al
      . Anxiety but not depression determines health care-seeking behaviour in Chinese patients with dyspepsia and irritable bowel syndrome: a population-based study. Aliment Pharmacol Ther 2002;16:2081–8. doi:10.1046/j.1365-2036.2002.01377.x
      OpenUrlCrossRefPubMed
    40. ↵
      1. Pan G,
      2. Lu S,
      3. Ke M, et al
      . Epidemiologic study of the irritable bowel syndrome in Beijing: stratified randomized study by cluster sampling. Chin Med J 2000;113:35–9.
      OpenUrlPubMed
    41. ↵
      1. Lau EM,
      2. Chan FK,
      3. Ziea ET, et al
      . Epidemiology of irritable bowel syndrome in Chinese. Dig Dis Sci 2002;47:2621–4. doi:10.1023/A:1020549118299
      OpenUrlCrossRefPubMedWeb of Science
    42. ↵
      1. Rajendra S,
      2. Alahuddin S
      . Prevalence of irritable bowel syndrome in a multi-ethnic Asian population. Aliment Pharmacol Ther 2004;19:707–14.
      OpenUrlCrossRefPubMed
    43. ↵
      1. Zang S,
      2. Zhang X,
      3. Chen J
      . Epidemiology of Irritable bowel syndrome in community population. J Comm Med 2007;5:19–20.
      OpenUrl
    44. ↵
      1. Chen Y,
      2. Liu S,
      3. Hao X, et al
      . Epidemiology study of irritable bowel syndrome in urban and rural population in Luohe China. Chin J Prac Nurs 2011;27:50–3.
      OpenUrl
    45. ↵
      1. Shen F,
      2. Chen G,
      3. Zhou H, et al
      . Correlation analysis of quality of sleep and irritable bowel syndrome in community population. Chin J Dig 2010;30:525–8.
      OpenUrl
    46. ↵
      1. Wu X,
      2. Chen J,
      3. Li Y, et al
      . Epidemiology study of irritable bowel syndrome in community population in Jieyang, Guangdong, China. Public Medical Forum Magazine 2007;11:18–19.
      OpenUrl
    47. ↵
      1. Fu Y,
      2. Li L,
      3. Fu Y
      . Epidemiology of irritable bowel syndrom and functional constipation in community population of Pindingshan China. Chin J Clin Gastro 2005;17:132–43.
      OpenUrl
    48. ↵
      1. Gwee KA,
      2. Wee S,
      3. Wong ML, et al
      . The prevalence, symptom characteristics, and impact of irritable bowel syndrome in an asian urban community. Am J Gastroenterol 2004;99:924–31. doi:10.1111/j.1572-0241.2004.04161.x
      OpenUrlCrossRefPubMedWeb of Science
    49. ↵
      1. Lee S,
      2. Wu J,
      3. Ma YL, et al
      . Irritable bowel syndrome is strongly associated with generalized anxiety disorder: a community study. Aliment Pharmacol Ther 2009;30:643–51. doi:10.1111/j.1365-2036.2009.04074.x
      OpenUrlCrossRefPubMed
    50. ↵
      1. Boyce PM,
      2. Koloski NA,
      3. Talley NJ
      . Irritable bowel syndrome according to varying diagnostic criteria: are the new Rome II criteria unnecessarily restrictive for research and practice? Am J Gastroenterol 2000;95:3176–83. doi:10.1111/j.1572-0241.2000.03197.x
      OpenUrlCrossRefPubMedWeb of Science
    51. ↵
      1. Zuckerman MJ,
      2. Nguyen G,
      3. Ho H, et al
      . A survey of irritable bowel syndrome in Vietnam using the Rome criteria. Dig Dis Sci 2006;51:946–51. doi:10.1007/s10620-005-9005-0
      OpenUrlCrossRefPubMed
    52. ↵
      1. Chen LY,
      2. Ho KY,
      3. Phua KH
      , Community Medicine GI Study Group. Normal bowel habits and prevalence of functional bowel disorders in Singaporean adults--findings from a community based study in Bishan. Singapore Med J 2000;41:255–8.
      OpenUrlPubMed
    53. ↵
      1. Aggarwal VR,
      2. McBeth J,
      3. Zakrzewska JM, et al
      . The epidemiology of chronic syndromes that are frequently unexplained: do they have common associated factors? Int J Epidemiol 2006;35:468–76. doi:10.1093/ije/dyi265
      OpenUrlAbstract/FREE Full Text
    54. ↵
      1. Ebling B,
      2. Jurcic D,
      3. Gmajni R, et al
      . Anthropological, demographic and socioeconomic characteristics of irritable bowel syndrome. Coll Antropol 2011;35:513–21.
      OpenUrlPubMed
    55. ↵
      1. Hillilä MT,
      2. Färkkilä MA
      . Prevalence of irritable bowel syndrome according to different diagnostic criteria in a non-selected adult population. Aliment Pharmacol Ther 2004;20:339–45. doi:10.1111/j.1365-2036.2004.02034.x
      OpenUrlCrossRefPubMedWeb of Science
    56. ↵
      1. Hungin AP,
      2. Whorwell PJ,
      3. Tack J, et al
      . The prevalence, patterns and impact of irritable bowel syndrome: an international survey of 40,000 subjects. Aliment Pharmacol Ther 2003;17:643–50. doi:10.1046/j.1365-2036.2003.01456.x
      OpenUrlCrossRefPubMedWeb of Science
    57. ↵
      1. Icks A,
      2. Haastert B,
      3. Enck P, et al
      . Prevalence of functional bowel disorders and related health care seeking: a population-based study. Z Gastroenterol 2002;40:177–83. doi:10.1055/s-2002-22324
      OpenUrlCrossRefPubMed
    58. ↵
      1. Karaman N,
      2. Turkay C,
      3. Yonem O
      . Irritable bowel syndrome prevalence in city center of Sivas. Turk J Gastroenterol 2003;14:128–31.
      OpenUrlPubMed
    59. ↵
      1. Katsinelos P,
      2. Lazaraki G,
      3. Kountouras J, et al
      . Prevalence, bowel habit subtypes and medical care-seeking behaviour of patients with irritable bowel syndrome in Northern Greece. Eur J Gastroenterol Hepatol 2009;21:183–9. doi:10.1097/MEG.0b013e328312eb97
      OpenUrlCrossRefPubMed
    60. ↵
      1. Kennedy TM,
      2. Jones RH
      . Epidemiology of cholecystectomy and irritable bowel syndrome in a UK population. Br J Surg 2000;87:1658–63. doi:10.1046/j.1365-2168.2000.01596.x
      OpenUrlCrossRefPubMedWeb of Science
    61. ↵
      1. Agréus L,
      2. Svärdsudd K,
      3. Talley NJ, et al
      . Natural history of gastroesophageal reflux disease and functional abdominal disorders: a population-based study. Am J Gastroenterol 2001;96:2905–14. doi:10.1111/j.1572-0241.2001.04680.x
      OpenUrlCrossRefPubMedWeb of Science
    62. ↵
      1. Olafsdottir LB,
      2. Gudjonsson H,
      3. Jonsdottir HH, et al
      . Stability of the irritable bowel syndrome and subgroups as measured by three diagnostic criteria—a 10-year follow-up study. Aliment Pharmacol Ther 2010;32:670–80. doi:10.1111/j.1365-2036.2010.04388.x
      OpenUrlPubMed
    63. ↵
      1. Osterberg E,
      2. Blomquist L,
      3. Krakau I, et al
      . A population study on irritable bowel syndrome and mental health. Scand J Gastroenterol 2000;35:264–8. doi:10.1080/003655200750024128
      OpenUrlCrossRefPubMedWeb of Science
    64. ↵
      1. Papatheodoridis GV,
      2. Karamanolis DG
      . Prevalence and impact of upper and lower gastrointestinal symptoms in the Greek urban general population. Scand J Gastroenterol 2005;40:412–21. doi:10.1080/00365520510012271
      OpenUrlCrossRefPubMed
    65. ↵
      1. Usai P,
      2. Manca R,
      3. Lai MA, et al
      . Prevalence of irritable bowel syndrome in Italian rural and urban areas. Eur J Intern Med 2010;21:324–6. doi:10.1016/j.ejim.2010.05.009
      OpenUrlCrossRefPubMed
    66. ↵
      1. Vandvik PO,
      2. Lydersen S,
      3. Farup PG
      . Prevalence, comorbidity and impact of irritable bowel syndrome in Norway. Scand J Gastroenterol 2006;41:650–6. doi:10.1080/00365520500442542
      OpenUrlCrossRefPubMedWeb of Science
    67. ↵
      1. Wilson S,
      2. Roberts L,
      3. Roalfe A, et al
      . Prevalence of irritable bowel syndrome: a community survey. Br J Gen Pract 2004;54:495–502.
      OpenUrlAbstract/FREE Full Text
    68. ↵
      1. Baretic M,
      2. Bilic A,
      3. Jurcic D, et al
      . Epidemiology of irritable bowel syndrome in Croatia. Coll Antropol 2002;26(Suppl):85–91.
      OpenUrlPubMed
    69. ↵
      1. Boekema PJ,
      2. van Dam van Isselt EF,
      3. Bots ML, et al
      . Functional bowel symptoms in a general Dutch population and associations with common stimulants. Neth J Med 2001;59:23–30. doi:10.1016/S0300-2977(01)00128-0
      OpenUrlCrossRefPubMedWeb of Science
    70. ↵
      1. Bommelaer G,
      2. Dorval E,
      3. Denis P, et al
      . Prevalence of irritable bowel syndrome in the French population according to the Rome I criteria. Gastroenterol Clin Biol 2002;26:1118–23.
      OpenUrlPubMed
    71. ↵
      1. Bommelaer G,
      2. Poynard T,
      3. Le Pen C, et al
      . Prevalence of irritable bowel syndrome (IBS) and variability of diagnostic criteria. Gastroenterol Clin Biol 2004;28:554–61. doi:10.1016/S0399-8320(04)95011-7
      OpenUrlCrossRefPubMed
    72. ↵
      1. Caballero-Plasencia AM,
      2. Sofos-Kontoyannis S,
      3. Valenzuela-Barranco M, et al
      . Irritable bowel syndrome in patients with dyspepsia: a community-based study in southern Europe. Eur J Gastroenterol Hepatol 1999;11:517–22. doi:10.1097/00042737-199905000-00009
      OpenUrlCrossRefPubMedWeb of Science
    73. ↵
      1. Dapoigny M,
      2. Bellanger J,
      3. Bonaz B, et al
      . Irritable bowel syndrome in France: a common, debilitating and costly disorder. Eur J Gastroenterol Hepatol 2004;16:995–1001. doi:10.1097/00042737-200410000-00008
      OpenUrlCrossRefPubMedWeb of Science
    74. ↵
      1. Gómez Alvarez DF,
      2. Morales Vargas JG,
      3. Rojas Medina LM, et al
      . [Prevalence of irritable bowel syndrome and associated factors according to the Rome III diagnostic criteria in a general population in Colombia]. Gastroenterol Hepatol 2009;32:395–400. doi:10.1016/j.gastrohep.2009.01.177
      OpenUrlCrossRefPubMed
    75. ↵
      1. Olmos JA,
      2. iantorno G,
      3. Guzmán M, et al
      . Irritable bowel syndrome: prevalence, comorbidity and impact. A population based study. Gut 2010;59(Suppl III):A361. doi:10.1136/gut.2009.208991i
      OpenUrlCrossRef
    76. ↵
      1. Iade B,
      2. Toma R
      . Frecuencia del síndrome de intestino irritable en una población de montevideo. Arch Med Int 2003;XXV:91–6.
    77. ↵
      1. Madrid-Silva AM,
      2. Defilippi-Caffri C,
      3. Landskron-Ramos G, et al
      . [The prevalence of irritable bowel symptoms in a population of shopping mall visitors in Santiago de Chile]. Rev Gastroenterol Mex 2013;78:203–10. doi:10.1016/j.rgmx.2013.07.004
      OpenUrlPubMed
    78. ↵
      1. Olguín F,
      2. Madrid AM,
      3. Catalá M, et al
      . Prevalenciia del síndrome de intestino irritable en población mapuche. Gastroenterol latinoam 2009;20:238.
      OpenUrl
    79. ↵
      1. Curioso WH,
      2. Donaires Mendoza N,
      3. Bacilio Zerpa C, et al
      . [Prevalence and relation of dyspepsia to irritable bowel syndrome in a native community of the Peruvian jungle]. Rev Gastroenterol Peru 2002;22:129–40.
      OpenUrlPubMed
    80. ↵
      1. Campos Hurtado G,
      2. Villareal Menchola J,
      3. Cornejo Zapata C, et al
      . [Prevalence of Manning's symptoms in a Lima upper socioeconomic level population]. Rev Gastroenterol Peru 2001;21:301–5.
      OpenUrlPubMed
    81. ↵
      1. Valerio-Ureña J,
      2. Vásquez-Fernández F,
      3. Jiménez-Pineda A, et al
      . Prevalencia del sińdrome de intestino irritable en población abierta de la ciudad de Veracruz, México. Rev Gastroenterol Mex. 2010;75:36–41.
      OpenUrlPubMed
    82. ↵
      1. Sander G,
      2. Francesconi CF,
      3. Mazzoleni LE, et al
      . Brazilian prevalence of irritable bowel syndrome: a population-based study. Gastroenterology 2008;134(Suppl. 1):A-217. doi:10.1016/S0016-5085(08)61001-X
      OpenUrl
    83. ↵
      1. Soares RL,
      2. dos Santos JM,
      3. Rocha VR
      . Prevalence of irritable bowel syndrome in a Brazilian Amazon community. Neurogastroenterol Motil 2005;17:883. doi:10.1111/j.1365-2982.2005.00722.x
      OpenUrlCrossRefPubMed
    84. ↵
      1. López-Colombo A,
      2. Morgan D,
      3. Bravo-González D, et al
      . The epidemiology of functional gastrointestinal disorders in Mexico: a population-based study. Gastroenterol Res Pract 2012;2012:606174. doi:10.1155/2012/606174
      OpenUrlPubMed
    85. ↵
      1. Schmulson M,
      2. Adeyemo M,
      3. Gutiérrez-Reyes G, et al
      . Differences in gastrointestinal symptoms according to gender in Rome II positive IBS and dyspepsia in a Latin American population. Am J Gastroenterol 2010;105:925–32. doi:10.1038/ajg.2010.58
      OpenUrlCrossRefPubMed
    86. ↵
      1. Schmulson M,
      2. Lopez-Colombo A,
      3. Mendoza-Gomez A, et al
      . The Rome III Adult Questionnaire in Spanish-Mexico has a low sensitivity for identifying IBS and higher sensitivity for uninvestigated dyspepsia. Gastroenterology 2012;143(Suppl 1):S-829. doi:10.1016/S0016-5085(12)63220-X
      OpenUrl
    87. ↵
      1. Veitia G,
      2. Gledhill T,
      3. Pernalete B, et al
      . Prevalencia del sindrome intenstino irritable en la poblacion adulta venezolana. Revista de la Sociedad Venezolana de Gastroenterogica 2011;65:266.
      OpenUrl
    88. ↵
      1. Morgan DR,
      2. Benshoff M,
      3. Cáceres M, et al
      . Irritable bowel syndrome and gastrointestinal parasite infection in a developing nation environment. Gastroenterol Res Pract 2012;2012:343812. doi:10.1155/2012/343812
      OpenUrlPubMed
    89. ↵
      1. Okeke EN,
      2. Ladep NG,
      3. Adah S, et al
      . Prevalence of irritable bowel syndrome: a community survey in an African population. Ann Afr Med 2009;8:177–80. doi:10.4103/1596-3519.57241
      OpenUrlPubMed
    90. ↵
      1. Yilmaz S,
      2. Dursun M,
      3. Ertem M, et al
      . The epidemiological aspects of irritable bowel syndrome in Southeastern Anatolia: a stratified randomised community-based study. Int J Clin Pract 2005;59:361–9. doi:10.1111/j.1742-1241.2004.00377.x
      OpenUrlCrossRefPubMed
    91. ↵
      1. Celebi S,
      2. Acik Y,
      3. Deveci SE, et al
      . Epidemiological features of irritable bowel syndrome in a Turkish urban society. J Gastroenterol Hepatol 2004;19:738–43. doi:10.1111/j.1440-1746.2004.03367.x
      OpenUrlCrossRefPubMedWeb of Science
    92. ↵
      1. Sperber AD,
      2. Shvartzman P,
      3. Friger M, et al
      . Unexpectedly low prevalence rates of IBS among adult Israeli Jews. Neurogastroenterol Motil 2005;17:207–11. doi:10.1111/j.1365-2982.2005.00623.x
      OpenUrlCrossRefPubMedWeb of Science
    93. ↵
      1. Sperber AD,
      2. Friger M,
      3. Shvartzman P, et al
      . Rates of functional bowel disorders among Israeli Bedouins in rural areas compared with those who moved to permanent towns. Clin Gastroenterol Hepatol 2005;3:342–8. doi:10.1016/S1542-3565(04)00553-1
      OpenUrlCrossRefPubMed
    94. ↵
      1. Khoshkrood-Mansoori B,
      2. Pourhoseingholi MA,
      3. Safaee A, et al
      . Irritable bowel syndrome: a population based study. J Gastrointestin Liver Dis 2009;18:413–18.
      OpenUrlPubMed
    95. ↵
      1. Hoseini-Asl MK,
      2. Amra B
      . Prevalence of irritable bowel syndrome in Shahrekord, Iran. Indian J Gastroenterol 2003;22:215–6.
      OpenUrlPubMed
    96. ↵
      1. Khademolhosseini F,
      2. Mehrabani D,
      3. Nejabat M, et al
      . Irritable bowel syndrome in adults over 35 years in Shiraz, southern Iran: prevalence and associated factors. J Res Med Sci 2011;16:200–6.
      OpenUrlPubMed
    97. ↵
      1. Schmulson M,
      2. Ortíz O,
      3. Santiago-Lomeli M, et al
      . Frequency of functional bowel disorders among healthy volunteers in Mexico City. Dig Dis 2006;24:342–7. doi:10.1159/000092887
      OpenUrlCrossRefPubMed
    98. ↵
      1. Miwa H
      . Life style in persons with functional gastrointestinal disorders--large-scale internet survey of lifestyle in Japan. Neurogastroenterol Motil 2012;24:464–71, e217. doi:10.1111/j.1365-2982.2011.01872.x
      OpenUrlCrossRefPubMed
    99. ↵
      1. Lijmer JG,
      2. Bossuyt PM,
      3. Heisterkamp SH
      . Exploring sources of heterogeneity in systematic reviews of diagnostic tests. Stat Med 2002;21:1525–37. doi:10.1002/sim.1185
      OpenUrlCrossRefPubMedWeb of Science
    100. ↵
      1. Sperber AD,
      2. DeVellis RF,
      3. Boehlecke B
      . Cross-cultural translation: methodology and validation. Journal of Cross-Cultural Psychology 1994;25:501–24. doi:10.1177/0022022194254006
      OpenUrlCrossRefWeb of Science
    101. ↵
      1. Sperber AD
      . Translation and validation of study instruments for cross-cultural research. Gastroenterology 2004;126:S124–8. doi:10.1053/j.gastro.2003.10.016
      OpenUrlCrossRefPubMedWeb of Science
    102. ↵
      1. Olubuyide IO,
      2. Olawuyi F,
      3. Fasanmade AA
      . A study of irritable bowel syndrome diagnosed by Manning criteria in an African population. Dig Dis Sci 1995;40:983–5. doi:10.1007/BF02064186
      OpenUrlCrossRefPubMed
    103. ↵
      1. Ghoshal UC,
      2. Abraham P,
      3. Bhatt C, et al
      . Epidemiological and clinical profile of irritable bowel syndrome in India: report of the Indian Society of Gastroenterology Task Force. Indian J Gastroenterol 2008;27:22–8.
      OpenUrlPubMed
    104. ↵
      1. Ghoshal UC,
      2. Abraham P,
      3. Bhatia SJ, et al
      . Comparison of Manning, Rome I, II, III, and Asian diagnostic criteria: Report of a multi-centric Indian irritable bowel syndrome (MIIBS) study. Indian J Gastroenterol 2013;32:369–75. doi:10.1007/s12664-013-0365-7
      OpenUrlCrossRefPubMed
    105. ↵
      1. Srivastava D,
      2. Ghoshal U,
      3. Mittal RD, et al
      . Associations between IL-1RA polymorphisms and small intestinal bacterial overgrowth among patients with irritable bowel syndrome from India. Neurogastroenterol Motil 2014;26:1408–16. doi:10.1111/nmo.12399
      OpenUrlCrossRefPubMed

    Footnotes

    • Contributors ADS was involved in the study concept and design; acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; statistical analysis. DD was involved in the study concept and design; acquisition of data; critical revision of the manuscript for important intellectual content. SF, CG, UCG, KAG, J-YK, MS, WW and APSH were involved in the study concept and design; acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content. CM was involved in the acquisition of data; critical revision of the manuscript for important intellectual content. AB, MF and TF were involved in the analysis and interpretation of data; critical revision of the manuscript for important intellectual content; statistical analysis. All authors approved the manuscript for submission.

    • Competing interests None declared.

    • Provenance and peer review Not commissioned; externally peer reviewed.