it is one of the most common and bothersome complaints in patients with functional gastrointestinal disorders ( 13 ) . bloating has a significant impact limiting the ability to perform normal daily activities ( 4 ) . bloating symptoms are common in patients with the irritable bowel syndrome ( ibs ) ( 5 ) . gas and including bloating bloating is often described as one of the more distressing symptoms associated with ibs ( 6 ) . bloating may result from increased gas production from bacterial fermentation of undigested food , retarded gas transit , and heightened sensitivity of the gut to normal luminal gas volumes , or dysfunctional abdominal wall musculature ( 7 ) . in one investigation , bloating was rated the most bothersome symptom by 60% of ibs patients , whereas 29% considered pain to be most intrusive ( 8) . in another study , up to 90% of ibs patients reported that they suffer from bloating ( 1 ) . abdominal distention and bloating are more often noted by women with ibs than men . in women most studies report a higher prevalence of bloating with constipation - predominant ibs than those with diarrhea predominant ibs , although some investigations report no relation of bloating to a particular defecation profile ( 1012 ) . bloating in ibs the purpose of this study was to describe the occurrence of self report bloating and related factors in patients with ibs . this study was a community - based cross - sectional survey conducted from may 2006 to december 2007 in the tehran province , iran . 4 cities and a small part of tehran , capital of iran , were included . collecting data and random selection were performed in the  national registry system  of iran and recruitment of participants were totally based upon national postal codes , and national i d numbers.19,200 adult persons ( > 18 years ) out of 10,000 000 residents of this area were randomly selected , of whom 18,180 persons gave their consent to be finally interviewed . these trained health personnel conducted door - to - door invitations . before the interview survey , the interviewer explained the purpose of these questions to all eligible individuals and requested their participation . the research protocol was approved by the ethics committee of research institute for gastroenterology and liver diseases , shahid beheshti medical university . participants were excluded if they were pregnant , had records of experiencing major psychotic episodes , mental retardation or dementia , hiatal hernia , or if they had significant illness that might have impaired their ability to complete the questionnaire . the questionnaire included two parts , the first part that was conducted by trained health personnel , consisted of questions , in which personal and family characteristics such as age , sex , occupation , educational level , household income , psychological factors including : self reported stress , anxiety and depression , catastrophic events such as death of a close relative , car accident , bankruptcy or sever disease and also about 11 gastrointestinal symptoms including ; abdominal pain or distress , constipation , diarrhea , bloating , heartburn , acid regurgitation , proctalgia , nausea and vomiting , fecal incontinence , existence of blood in the stool or black stool ( melaena ) , weight loss or anorexia , and difficulty in swallowing ( 1416 ) . those who reported any of the above symptoms were referred to assigned physicians to be questioned about symptoms of ibs according to the rome iii criteria . the accuracy of translation was controlled by several courses in translation between persian and english . the validity and reliability of the persian questionnaire was tested in advance in a pilot study on 400 participants from city of damavand . for validity study , the test  retest reliability was good and the cronbach alpha coefficient values were above 0.7 for all of the major symptoms included in the tool . irritable bowel syndrome was defined as an individual who met rome iii criteria as follows ; at least 3 months , associated two or more of criteria below : 1 ) improvement with defecation ; 2 ) onset associated with a change in frequency of stool ; 3 ) onset associated with a change in form ( consistency ) of stool . continuous variables are presented as mean  standard deviation or median , and other parameters as frequency and percentage . a p - value of 0.05 or less was considered statistically significant and all reported p values were two sided . out of 18180 subjects under study , 198 cases met irritable bowel syndrome according to criteria rome iii , of which 139 were female and 59 were male . forty - four ibs patients ( 22% ) were younger than 30 years , 65 were aged between 30 and 45 , and 89 more than 45 years ( table 1 ) . demographic characteristics of subjects under study one hundred and eighty - six ibs patients ( 94% ) had abdominal discomfort or pain that was relieved by defecation . 70% ( n=139 ) reported that onset associated with a change in frequency of stool and 75% with a change of consistency of stool . the pain was periumblical in about half of the ibs patients : 79 patients had epigastric and 37 had hypogastric pain . the least likely sites of pain were left upper ( 6% ) and right upper quadrants ( 3% ) , respectively . constipation was predominant in 52% of ibs cases ( ibs - c ) , diarrhea was predominant in 17.7% ( ibs - d ) , and 8.1% experienced intermittent diarrhea and constipation ( ibs - i ) . of the 198 ibs patients in this study , 61.6% ( n= 122 ) reported bloating symptoms , the first most bothersome symptom . no significant difference observed between men and women regarding bloating symptom but perimenopausal women were most suffer from bloating(p<0.05 ) . also , older 45 years persons reported bloating symptoms higher than younger , but this difference was not significant . bloating symptoms were more prevalent in those with intermittent changes in stool frequency than in patients with continuus diarrhoea or constipation ( p>0.05 ) . bloating symptoms were rated as the most bothersome symptom in three groups . bloating symptom was not influenced by body mass index ( bmi ) , stress and anxiety but catastrophic events and depression were increase sensation of bloating table 2 . distribution of bloating symptom according to sex , age , bmi , ibs subtype and psychological factors our findings support the high prevalence and the considerable effect of bloating symptoms in patients with ibs . more than 60% of the patients participated in our study . bloating symptoms were reported 58.3 , 65.7 and 81.3% by ibs - c , ibs - d and ibs - i , respectively that is inconsistent with previous reports that noted high prevalence of bloating in ibs - c patients ( 5 , 11 ) . the differences between these studies might relate to differences in the patient s population because unlike our study that recruited from a general population , more than half of the participants in the mentioned studies were from tertiary referral centers . in present study there was no significant difference in the prevalence of bloating observed between men and women . on further analysis , peri - menopausal women had significantly bloating symptoms than other patient groups ( 17 ) . bloating symptoms were found to be increased in relation to female patients menses and to be associated with symptoms of uterine cramping and breast tenderness in perimenopausal women with ibs . the reported gender differences might also represent differences in sensory processes , autonomic responses , and/or cognitive hypervigilance ( 9 ) . in terms of the most bothersome symptoms , we found that bloating symptoms were rated as the most bothersome symptom in ibs patients . although some studies indicate that bloating in ibs may be worsened by stress and relieved by relaxation ( 13 ) , our study did not identify a significant association between stress and anxiety with bloating , but depression and catastrophic events had direct impression on rate of bloating . a limitation of this study is the lack of a healthy control group to enable comparison of our findings regarding the prevalence of these symptoms with their prevalence in the healthy population . another limitation of our study is that the information was based on questionnaire and self - reporting reports and it was not possible to evaluate the accuracy of self - reported bloating and psychological factors . in conclusion , this results support the clinical impression regarding the high prevalence and considerable impact of bloating symptoms in patients with ibs . we found that the prevalence and relative severity of bloating symptoms differ by ibs subtype , psychological factors and that these symptoms are associated with decrease in qol and increase in healthcare utilization and use of medications . studies targeted to psychological distress in patients with ibs could help health care providers more fully understand the components of disabling symptom clusters .
aimthe purpose of this study was to describe the occurrence of self report bloating and related factors in patients with irritable bowel syndrome ( ibs).backgroundbloating symptoms are common in patients with ibs and have significant impact on normal daily function.patients and methodsthis study was a community - based cross - sectional survey that conducted using a valid questionnaire base on rome iii criteria . 
 univariate analysis was used for investigation about distribution of self reported bloating according to demographic and psychological factors in irritable bowel syndrome patients.resultsout of 18180 subjects under study , 198 cases met criteria for the diagnosis of the irritable bowel syndrome according to criteria rome iii and 61.6% reported bloating symptoms . 
 bloating symptoms were more prevalent among patients with intermittent symptoms and diarrhea than in patients with constipation . catastrophic events and depression were independent risk factors for bloating.conclusionfindings of this study support the clinical impression regarding the high prevalence of bloating symptoms in patients with irritable bowel syndrome . 
 further studies are needed to understand the role of physiological and psychological factors and their interaction in development of bloating in irritable bowel syndrome patients .