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CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2009;7:6872loating, distention, and gas are very common complaintsamong patients seen in primary care and gastrointestinal

I) clinics. Epidemiologic studies indicate that bloating symp-s are reported by 10%30% of the general population.1 4 A

tional, cross-sectional, telephone survey of U.S. householdsa total of 2510 subjects found that more than 70% of

ividuals who experience bloating or distention rate theseptoms as moderate to severe, and more then 50% reporte reduction in their daily activities as a result of these

MethodsThis study included 337 people who had IBS over

time, on the basis of 2 surveys. In the original survey con-ducted between December 2001 and February 2002, a sampleof 31,829 people was drawn from an existing web-enabled

Abbreviations used in this paper: GI, gastrointestinal; IBS, irritablebowel syndrome; IBS-C, constipation-predominant IBS; IBS-D, diarrhea-predominant IBS; IBS-M, IBS with mixed symptoms; QOL, quality oflife.revalence, Characteristics, and Impaatients With Irritable Bowel Syndrom

HUDA RINGEL,* RACHEL E. WILLIAMS, LINDA KALILANI,

ision of Gastroenterology and Hepatology and Department of Epidemiology, UxoSmithKline, Research Triangle Park, North Carolina

odcast interview: www.cghjournal.org; see CMExam on page 3; see editorial on page 7.

ckground & Aims: Bloating symptoms are commonpatients with irritable bowel syndrome (IBS) seen inmary care and gastrointestinal clinics. However, the un-rlying mechanisms of IBS are poorly understood, andre are few data available about the epidemiology of thisdrome or the impact of its symptoms. We investigatedprevalence, characteristics, and impact of bloatingptoms in patients with IBS. Methods: IBS patients

re identified by Rome II criteria in a U.S. populationresentative web-based survey. Patients were asked aboutquality, frequency, and severity of their gastrointestinalptoms. The impact of these symptoms was investigatedassessing patients health-related quality of life, utiliza-n of health care, and use of medications. Results: Of337 IBS patients in this study, 82.5% (n 278) reportedating symptoms, the second most bothersome symptomer abdominal cramping. The symptoms were more preva-t in female patients, 87.4% (n 209), than inmale patients,4% (n 69) (P< .0001), and in patients with constipation,7% (n 47), andmixed symptoms, 88.8% (n 135), than intients with diarrhea, 72.3% (n 96), (P .02 and P < .01,pectively). Bloating symptoms were the third (of 14) mostportant reason to seek medical care, and more than half ofpatients reported regular use of anti-gas medications.ating symptoms were associated with decreased energyels (P .04), food intake (P < .01), and physical function-(P .06). Conclusions: Bloating symptoms are com-n in patients with IBS, and their prevalence and relativeerity differ on the basis of sex and IBS subtype. Bloatingptoms. Furthermore, 43% take medications and 16% soughtdical advice for these symptoms.4of Bloating Symptoms in

SUZANNE F. COOK

ty of North Carolina, Chapel Hill; and Worldwide Epidemiology,

Irritable bowel syndrome (IBS) is the most common func-nal GI disorder, with a prevalence of 10%20% in the adultpulation in the Western world.5,6 The typifying clinical pre-tation of IBS is abdominal pain or discomfort associatedh altered bowel habits and change in the consistency orquency of stools. However, IBS symptoms are heterogeneoustheir expression and often overlap with other GI symptomsluding bloating and distention. Indeed, abdominal bloating

d distention were originally reported by Manning et al7 as 16 factors that discriminate IBS from organic conditions andre included in the criteria for the diagnosis of the disorder.hough the more recent diagnostic criteria for IBS, developedmultinational working committees and later known as Rometeria, do not include bloating and distention, it has beengested that when/if present, these symptoms increase thefidence in the diagnosis and might be used to identifygroups of IBS.8 10

Functional bloating is now defined as a separate conditiondistinct patients who have these symptoms and do not meetcriteria for IBS. The syndrome/condition is suggested as

t of the larger group of functional bowel disorders and isned as a recurrent sensation of abdominal distention that

y or may not be associated with measurable distention but ist part of another functional bowel or gastroduodenal disor-.10

Although considered 2 separate distinct diagnoses, it is verymon in clinical practice to see patients with IBS diagnosis

o also complain of bloating symptoms including abdominaltention and gas. Although supportive of this clinical impres-n, the published data on the overlap between the 2 condi-ns are very limited.In this epidemiologic study we investigated the prevalence,racteristics, and impact of bloating symptoms, including 2009 by the AGA Institute1542-3565/09/$36.00

doi:10.1016/j.cgh.2008.07.008

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January 2009 PREVALENCE, CHARACTERISTICS, AND IMPACT OF BLOATING SYMPTOMS IN IBS 69earch panel consisting of more than 150,000 householdmbers who were representative of the U.S. populationd 21 65 years. The panel was recruited through proba-

ity sampling techniques and stratified random-digit dial-. A more detailed description of the panel recruitment hasn published elsewhere.11,12

All recruited participants were sent a questionnaire designedscreen for symptoms consistent with a slightly modifiedme II classification of IBS, designed for ease of self-admin-ation.Subjects were considered to have IBS if they answered yes toquestion, Have you ever had continuous or repeated pain,

mping, or discomfort in your abdomen for at least 12 weeksich need not be consecutive) in the past 12 months? and

ected at least 2 of the following choices in response to theestion, In the past 12 months, which if any of the followingve you experienced in combination with abdominal pain,mping, or discomfort (select all that apply)? (A) Relief fromominal pain, cramping, or discomfort with a bowel move-

nt; (B) More frequent bowel movements; (C) Fewer bowelvements; (D) Loose or watery stools; (E) Firmer or harderols; (F) None of the above. IBS subtypes were based onponses to the second question. Diarrhea-predominantS-D) subjects were defined as those who reported at least 2 oftcomes A, B, and D but not C or E. Constipation-predomi-nt (IBS-C) subjects were defined as those who reported atst 2 of outcomes A, C, and E but not B or D. Those whoorted outcomes of B and/or D and C and/or E were definedmixed type (IBS-M).In the original survey, 1713 individuals met the Rome IIteria for IBS. In 2004, we contacted these IBS participants for

follow-up survey. At that time, 821 (48%) were still avail-le to contact in 2004. Of these, 697 (85%) agreed torticipate and completed a 30-minute web-based question-ire. Of the 697 with IBS in 2002, 337 (48%) met the criteria

IBS in the 2004 follow-up survey. These 337 people wereluded in our current analyses. A more detailed description of

over time has been published elsewhere.12

Subjects were asked to respond to questions regarding theality, frequency, and severity of their GI and non-GI symp-

s, comorbid conditions, and healthcare-seeking behavior.is article focuses on the prevalence, characteristics, and im-t of bloating symptoms. The findings with regard to other-related symptoms are reported elsewhere.11,12 Bloating pa-

nts were defined as those reporting having symptoms ofoating or feeling of abdominal fullness or distension, orelling during the past 12 months. Participants were askedich symptoms made them see a doctor during the past 12nths, what was the most important reason for which theya doctor for abdominal symptoms, and to rank the 3 most

thersome symptoms. The impact of bloating symptoms wasestigated by assessing the following variables: health-relatedality of life (QOL) by using the IBS-QOL, utilization oflthcare by frequency of doctor visits, use of IBS and anti-gasdications. Both the initial survey and the follow-up studyeived approval by the institutional review board of Northrolina Research Triangle Institute.

All analyses were conducted with SAS version 8.2 (SAS In-ute Inc, Cary, NC). Differences in categorical variables wereted with 2 tests. An alpha level of .05 was used in theermination of statistical significance.

MSWResultsDemographicsThe descriptive demographic characteristics of the

dy sample are shown in Table 1. Women comprised nearly% of the sample. Eighty-four percent were white, and 56%re married. The majority of the participants were 45 years oldolder (68%) and had at least a high school education (93%).e median reported household income was diverse (no lessn 15% or more than 25% in each category). Among the 337pondents, 132 (39.2%) were IBS-D, 53 (15.7%) were IBS-C,d 152 (45.1%) were IBS-M.

Prevalence of Bloating and DistentionSymptomsOf 337 IBS patients who participated in the study, 278

.5%) reported bloating symptoms. Bloating symptoms werere prevalent in women, 87.4% (n 209), than in men, 70.4%

ble 1. Demographics of the Study Population

Subjects with IBS(n 337), n (%)

subtype in 2004 surveyiarrhea 132 (39.2)onstipation 53 (15.7)lternator or mixed 152 (45.1)

nderale 98 (29.1)

emale 239 (70.9)(y)35 28 (8.3)544 78 (23.1)554 127 (37.7)5 104 (30.9)t year household income before taxesess than $20,000 76 (24.4)20,000$34,999 45 (14.5)35,000$49,999 78 (25.1)50,000$74,999 58 (18.6)75,000 or more 54 (17.4)rital statusarried 190 (56.4)ot married 147 (43.6)hest completed education leveless than high school 23 (6.8)igh school 89 (26.4)ome college 136 (40.4)achelors degree or higher 89 (26.4)e/ethnicityhite, non-Hispanic 283 (84.0)lack/African American, non-Hispanic 30 (8.9)ther, non-Hispanic 6 (1.8)ispanic 18 (5.3)rent employment statusorking 179 (53.1)ot working 80 (23.7)isabled 78 (23.1)

ographic regionortheast 38 (11.3)

idwest 136 (40.4)outh 94 (27.9)est 69 (20.5)

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70 RINGEL ET AL CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Vol. 7, No. 1 69) (P .0001), and in patients with constipation (IBS-C),.7% (n 47), and mixed symptoms (IBS-M), 88.8% (n 135),n in patients with diarrhea (IBS-D), 72.3% (n 96) (P .02

d P .01, respectively) (Figure 1). After abdominal painported in 100% of the patients), bloating symptoms were thest common reported symptom in IBS-C and IBS-M sub-ups and the second most common symptom in the IBS-Dgroup, preceded only by urgency 92.4% (n 122).

Table 2 shows the order of bothersome symptoms in theal IBS population (n 337). Bloating symptoms were ratedthe second most bothersome symptom, preceded only byominal cramping and followed by abdominal pain and

wel-related symptoms such as loose or watery stools, strain-, and urgency.

ImpactIBS patients with bloating symptoms sought signifi-

tly more healthcare for their abdominal symptoms duringlast year than those without bloating symptoms (17% vs 5%ght care 4 or more times, respectively; P .01). Symptomst made participants decide to see a doctor during the past 12nths are shown in Table 3. Bloating symptoms were foundbe the third most prevalent reason to seek out medical care

ure 1. Prevalence of bloating symptoms by gender and subtypesBS.

ble 2. Order of Bothersome Symptoms in the PopulationWith IBS (n 337)

Symptoms Frequency (%)

ominal cramping 47 (13.9)ating or feeling of fullness/distention/swelling 43 (12.8)ominal pain or discomfort 38 (11.3)se/watery stool 33 (9.8)

aining to have bowel movements 31 (9.2)ency 29 (8.6)r that abdominal symptoms related to cancerr another illness

28 (8.3)

re frequent bowel movements 26 (7.7)ing control of bowels, bowel accidents, soilingnderwear

16 (4.7)

ling of not having complete bowel movements 15 (4.5)

er/harder stools 11 (3.3)er bowel movements 10 (3.0)sage of mucus with bowel movements 5 (1.5)

RolFooSexpatients with IBS, preceded only by abdominal pain orcomfort and abdominal cramping. Bloating symptoms led toking medical care more than fear that the abdominal symp-

s relate to cancer or other illness and more than bowelbitrelated symptoms such as urgency, loose or watery stools,d for straining, and feeling of not having complete bowelvements.Patients with IBS and bloating scored lower on 3 of the 8mains of the IBS-QOL, compared with patients withoutating symptoms. Patients with bloating had significantlyer scores on energy (62.4 vs 71.3, P .04), food intake (65.1

75.9, P .01) and had a trend toward lower physical func-ning (70.1 vs 78.6, P .06) (Table 4). More than half (n 5) of the IBS patients reported use of anti-gas medications.

DiscussionPrevious epidemiologic studies pointed out the high

valence of bloating and gas symptoms in patients with IBS.wever, these studies were done mostly on tertiary referralpulation and did not aim to specifically investigate bloating

ptoms.1318 This epidemiologic study focuses on bloatingptoms in patients with IBS in a nonreferral setting and

estigates the prevalence, characteristics, and impact on theseptoms in these patients. Our study supports the clinical

pression about the high prevalence and the considerable

ble 3. Symptoms That Made Participants Decide to Seea Doctor During the Past 12 Months

Symptoms Frequency (%)

ominal pain or discomfort 125 (37.1)ominal cramping 108 (32.0)ating or feeling of fullness/distention/swelling 95 (28.2)ency 85 (25.2)r that abdominal symptoms related to cancerr other illness

81 (24.0)

se/watery stools 76 (22.6)re frequent bowel movements 62 (18.4)aining to have bowel movements 58 (17.2)ling of not having complete bowel movements 54 (16.0)ing control of bowels, bowel accidents, soilingnderwear

53 (15.7)

sage of mucus with bowel movements 42 (12.5)er/harder stools 35 (10.4)er bowel movements 34 (10.1)ers 9 (2.7)

ble 4. Quality of Life (IBS-QOL) by Presence of BloatingSymptoms

Domain Bloating No bloating P value

otional 56.4 56.5 .97ntal health 75.8 80.8 .18ep 72.2 77.0 .16rgy 62.4 71.3 .038sical functioning 70.1 78.6 .057ial functioning 61.0 63.4 .58

e physical 58.8 60.6 .70d 65.1 75.9 .0008ual life 73.4 79.8 .22

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January 2009 PREVALENCE, CHARACTERISTICS, AND IMPACT OF BLOATING SYMPTOMS IN IBS 71ect of bloating symptoms in patients with IBS. More than% of the patients participating in our study reported bloating

ptoms, with significantly higher prevalence in women.4%) than in men (70.4%) and in patients with IBS-C (88.7%)

d IBS-M (88.8%) than in patients with IBS-D (72.3%). Thesedings are consistent with previous anecdotal reports. In ady investigating symptom differences in patients with IBSthe basis of predominant bowel habits by using a mixedup of 53% clinical referrals to a tertiary care center and 47%ients who responded to advertisement, Schmulson et al13

orted that the most typical lower GI symptoms in both-C and IBS-D were bloating-type symptoms, with no differ-es between the 2 groups (88.6% and 88.4%, respectively). In

other study done entirely on tertiary referral patients, Lemboal14 studied symptom prevalence in patients with pain-pre-minant IBS. The most common symptoms in this study were

(76%) and bloating (66%). Cluster analyses that were used tossify the patients into groups on the basis of their predom-nt symptom identified the following 4 subgroups: (1) ab-minal pain; (2) bloating-type symptoms (including gas, bloat-, fullness, and distention); (3) incomplete rectal evacuation;

d (4) extra-abdominal symptoms (eg, chest pain and nausea).erestingly, analysis of the prevalence of the 4 groups showedt the subgroup with bloating-type symptoms was the mostmon (48%) followed by the subgroups with abdominal pain

%), incomplete rectal evacuation (16%), and extra-abdominalptoms (7%).

In terms of the most bothersome symptom, we found thatating symptoms were rated as the second most bothersomeptom in IBS patients, preceded only by abdominal cramp-

, and were the third (of 14) most important reason to seekdical care. These findings are similar to what was reported intudy by Lembo et al,14 which found that the single mostthersome symptom was abdominal pain (29%) followed bysation of gas (22%) and sensation of fullness and bloatingh abdominal distention (17%).The prevalence of bloating symptoms in the different sub-es of IBS was previously reported in 2 studies. Similar to ourdy findings, Talley et al15 reported higher prevalence ofating symptoms in patients with IBS-C (75%) than in pa-

nts with IBS-D (40.9%). Schmulson et al13 reported no dif-ence in the prevalence of bloating symptoms between IBS-Cd IBS-D (88.6% and 88.4%, respectively; P NS), although

latter study did report that the severity ratings for bloatingptoms were significantly higher in the IBS-C patients com-

ed with the IBS-D patients. The differences between thesedies might relate to differences in the patient populationause unlike our study that was done on general population,re than half of the participants in the study by Schmulson etnd all the participants in the study by Tally et al were from

tiary referral centers.Our finding of significantly higher prevalence of bloating

ptoms in women compared with men is consistent with ady on gender-related differences in IBS symptoms done ontiary referral patients. In this study, Lee et al16 reported that

pared with male patients, female patients have significantlyre abdominal distention associated with a sensation of

ating (65% vs 47%, P .001), despite similar levels of IBSerity, abdominal pain, psychological symptoms, and illnesspact. It is possible that these gender differences relate to theects of female hormones because bloating symptoms were

utitorednd to be increased in relation to female patients menses16

d to be associated with symptoms of uterine cramping andast tenderness in perimenopausal women with IBS.17 Theorted gender differences might also represent differences insory processes, autonomic responses, and/or cognitive hy-vigilance.With regard to the impact of bloating symptoms on theients overall well-being, Park et al18 found that comparedh patients with minimal or mild bloating, patients withderate to severe bloating report more daily symptoms of

xiety and depression, have more history of depressive disor-s, and exhibit higher psychological distress. It is not clearether these psychological symptoms are the result or these of the more severe bloating symptoms in these patients.wever, it has been suggested that bloating symptoms in IBSght be worsened by stress and relieved by relaxation.19 Ourdy showed that bloating symptoms are associated with arease in QOL because patients with bloating symptomsort having significantly lower energy and food intake, andy tend to have lower physical functioning. We also found anrease in healthcare utilization and use of medications forominal symptoms. There are no data on the use of medica-

ns for bloating symptoms in patients with IBS. However, aent study on the use of tegaserod in routine clinical practiceCanada20 showed that bloating was the second most frequent

ptom for prescribing this medication (80%), preceded onlyabdominal pain/discomfort (87%) and more than for con-ation (75%).

Our study focused on bloating symptoms in patients with. However, it should be noted that bloating symptoms

ght often be a consequence of nonfunctional conditionsh as small bowel bacterial overgrowth or colonic bacterial

mentation of malabsorbed nutrients in certain malabsorp-e conditions or celiac sprue. For example, a recent studyking at strategies for detection of celiac in a primary careting found that bloating was the most frequent reason for

initial screening in patients who were eventually diagnosedh celiac disease.21

In this study we grouped together several heterogeneousating-related symptoms, including feeling of bloating, full-s, abdominal distention, and gas, despite the theoretical

ssibility that each of these symptoms might represent aferent pathophysiologic mechanism that is yet to be discov-d. The decision to address these symptoms under a singlem of bloating symptoms was based on the recognition thatse symptoms often come together with significant overlap,

d many patients have difficulty in discriminating betweenm. Another limitation of our study is the lack of a healthytrol group to enable direct comparison of our study find-s regarding the prevalence of these symptoms with theirvalence in the general population.In conclusion, our study results support the clinical impres-n regarding the high prevalence and considerable impact ofating symptoms in patients with IBS. We found that thevalence and relative severity of bloating symptoms differ byder and the IBS subtype, and that these symptoms are

ociated with decrease in QOL and increase in healthcare

lization and use of medications. Further studies are neededinvestigate the relative contribution of treatment aiming touce bloating symptoms in patients with IBS, in improving

patients overall well-being and QOL, and reducing healthcareutilization and medication costs.

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irritable bowel syndrome in a British urban community: consultersand nonconsulters. Gastroenterology 1992;102:19621967.

2. Drossman DA, Li Z, Andruzzi E, et al. US householder survey offunctional gastrointestinal disorders: prevalence, sociodemogra-phy and health impact. Dig Dis Sci 1993;38:15691580.

3. Talley NJ, Boyce P, Jones M. Identification of distinct upper andlower gastrointestinal symptom groupings in an urban population.Gut 1998;42:690695.

4. Sandler RS, Stewart WF, Liberman JN, et al. Abdominal pain,bloating, and diarrhoea in the United States: prevalence andimpact. Dig Dis Sci 2000;45:11661171.

5. Mitchell CM, Drossman DA. Survey of the AGA membership relat-ing to patients with functional gastrointestinal disorders. Gastro-enterology 1987;92:12821284.

6. Drossman DA, Camilleri M, Mayer EA, et al. AGA technical reviewon irritable bowel syndrome. Gastroenterology 2002;123:21082131.

7. Manning AP, Thompson WG, Heaton KW, et al. Towards positive

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13

moderate to severe IBS patients based on predominant bowelhabit. Am J Gastroenterol 1999;94:29292935.

14. Lembo T, Naliboff B, Munakata J, et al. Symptoms and visceralperception in patients with pain-predominant irritable bowel syn-drome. Am J Gastroenterol 1999;94:13201326.

15. Talley NJ, Dennis EH, Schettler-Duncan VA, et al. Overlappingupper and lower gastrointestinal symptoms in irritable bowelsyndrome patients with constipation and diarrhea. Am J Gastro-enterol 2003;98:24542459.

16. Lee OY, Mayer EA, Schmulson M, et al. Gender-related differ-ences in IBS symptoms. Am J Gastroenterol 2001;96:21842193.

17. Heitkemper MM, Cain KC, Jarrett ME, et al. Relationship ofbloating to other GI and menstrual symptoms in women withirritable bowel syndrome. Dig Dis Sci 2004;49:8895.

18. Park HJ, Jarrett M, Cain K, et al. Psychological distress and GIsymptoms are related to severity of bloating in women withirritable bowel syndrome. Res Nurs Health 2008;31:98107.

19. Chang L, Lee OY, Naliboff B, et al. Sensation of bloating andvisible abdominal distension in patients with irritable bowel syn-drome. Am J Gastroenterol 2001;96:33413347.

20. Bradette M, Wawer AR, Balshaw R, et al. Characteristics, diag-nostic and symptom profile of patients receiving tegaserod in

21

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72 RINGEL ET AL CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Vol. 7, No. 1diagnosis of the irritable bowel. Br Med J 1978;2:653654.Drossman DA, Richter JE, Talley NJ, et al. The functional gastro-intestinal disorders: diagnosis, pathophysiology and treatment.1st ed. McLean, VA: Degnon Associates, 1994.Drossman DA, Corazziari E, Talley NJ, et al. Rome II: the func-tional gastrointestinal disordersdiagnosis, pathophysiologyand treatment: a multinational consensus. 2nd ed. McLean, VA:Degnon Associates, 2000.

. Longstreth GF, Thompson WG, Chey WD, et al. Functional boweldisorders. Gastroenterology 2006;130:14801491.

. Williams RE, Black CL, Kim HY, et al. Determinants of healthcare-seeking behaviour among subjects with irritable bowel syndrome.Aliment Pharmacol Ther 2006;23:16671675.

. Williams RE, Black CL, Kim HY, et al. Stability of irritable bowelsyndrome using a Rome II-based classification. Aliment Pharma-col Ther 2006;23:197205.

. Schmulson M, Lee OY, Chang L, et al. Symptom differences inroutine clinical practice in Canada. Can J Clin Pharmacol 2007;14:291300.

. Catassi C, Kryszak D, Louis-Jacques O, et al. Detection of Celiacdisease in primary care: a multicenter case-finding study in NorthAmerica. Am J Gastroenterol 2007;102:14541460.

ddress requests for reprints to: Yehuda Ringel, MD, University ofrth Carolina at Chapel Hill, Department of Medicine, Division ofstroenterology and Hepatology, 4107 BioInformatics Bldg, CB#80, 130 Mason Farm RD, Chapel Hill, NC 27599-7080. e-mail:el@med.unc.edu; fax: 919-843-0800.he authors disclose the following: Y. R. is supported by K23 grant075621. R. E. W. and S. F. C. are employees of GlaxoSmithKlinehave equity interest in GlaxoSmithKline. L. K. received an unre-

cted educational grant from GlaxoSmithKline to work on this re-rch.

Prevalence, Characteristics, and Impact of Bloating Symptoms in Patients With Irritable Bowel SyndromeMethodsResultsDemographicsPrevalence of Bloating and Distention SymptomsImpact

DiscussionReferences