The epidemiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed.

Indication of immune activation in patients with perceived food hypersensitivity

Majority of the patients with perceived food hypersensitivity have irritable bowel syndrome (IBS), and a significant proportion of IBS patients also attribute their gastrointestinal complaints to food items. Different factors such as disturbed intestinal fermentation, enteric dysmotility, post-infectious changes and altered microbial flora in the colon as well as psychological disturbances likely play a role in the pathophysiology and symptoms generation in patients with food hypersensitivity. In addition, a number of studies in these patient groups indicate that local, systemic and mucosal immune systems are activated. The question now is no longer intestinal immune activation, but how the immune system is activated in these patients. In the following review, the potential pathogenetic role of the immune system and evidence of immune activation are reported in patients with perceived food hypersensitivity.

The prevalence and clinical characteristics of primary headache in irritable bowel syndrome: a subgroup of the functional somatic syndromes

CONTEXT

The irritable bowel syndrome and primary headache are two chronic diseases characterized by symptoms of recurring pain and affect approximately 10%-20% of the general population.

OBJECTIVES

To study the prevalence of primary headache in volunteers with irritable bowel syndrome in a Brazilian urban community.

METHODS

It was evaluated the prevalence of primary headache associated with irritable bowel syndrome in adult volunteers 330 no patients.The protocol included the Rome III criteria, international classification of Headaches, later divided into four groups: I- Irritable bowel syndrome (n = 52), II- Primary headache (n = 45), III-Irritable bowel syndrome (n = 26) and headache, and IV- Controls (207).

RESULTS

We not found significant difference in the average age of the four groups and the diagnosis of irritable bowel syndrome, primary headache and their association was more frequent in females. The frequent use of analgesics was greater in groups II and III.

CONCLUSION

Our results suggest that irritable bowel syndrome and primary headache are also common in third world countries. The frequency in use of analgesics in association between the two entities was relevant. The identification of irritable bowel syndrome patients with different clinical sub-types could improve the therapeutics options and the prevention strategies.

Comorbidities in patients with irritable bowel syndrome with constipation or chronic idiopathic constipation: a review of the literature from the past decade

BACKGROUND

Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are common functional bowel disorders. Patients with IBS-C or CIC often present with ≥ 1 comorbidity that coincides with either of these conditions. These comorbidities may make underappreciated contributions to the patient's overall disease burden.

OBJECTIVE

To identify the comorbidities that are the most frequently reported in patients with IBS-C or CIC in the medical literature.

METHODS

A literature search (January 2001-March 2012) was performed using the Medline and Medline In-Process databases. Studies of adult patients with IBS-C or CIC were selected, and the prevalence rates of the comorbidities were extracted and analyzed according to the body system affected.

RESULTS

A total of 70 distinct comorbidities were identified from 35 published studies. These comorbidities involved several body systems, including the gastrointestinal, genitourinary, psychiatric, endocrine, and allergic or immunologic systems. Functional dyspepsia and depression were the most common comorbidities in patients with IBS-C, whereas functional dyspepsia, diabetes, and depression were the most common comorbidities in patients with CIC.

CONCLUSION

Patients with IBS-C or CIC frequently experience a wide range of comorbidities that contribute to their disease burden. Thus, we believe that medical professionals should consider common comorbidities when diagnosing and treating patients with IBS-C or CIC.

Diet and functional abdominal pain in children and adolescents

Functional abdominal pain (FAP) is a common complaint among children and adolescents. For many patients, symptoms exacerbate with eating. This review discusses findings concerning the role of diet in FAP. The foods that are discussed are divided into 2 major groups: food allergies or intolerances, which focus on milk, gluten, and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; and functional foods, which hone in on foods that reduce abdominal pain in adolescents such as fiber, peppermint oil, and probiotics. Lastly, we discuss the role of eating habits in FAP and how the physiology of eating may be the real culprit of symptoms associated with eating.

Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis

BACKGROUND & AIMS

Many cross-sectional surveys have reported the prevalence of irritable bowel syndrome (IBS), but there have been no recent systematic review of data from all studies to determine its global prevalence and risk factors.

METHODS

MEDLINE, EMBASE, and EMBASE Classic were searched (until October 2011) to identify population-based studies that reported the prevalence of IBS in adults (≥15 years old); IBS was defined by using specific symptom-based criteria or questionnaires. The prevalence of IBS was extracted for all studies and based on the criteria used to define it. Pooled prevalence, according to study location and certain other characteristics, odds ratios (ORs), and 95% confidence intervals (CIs) were calculated.

RESULTS

Of the 390 citations evaluated, 81 reported the prevalence of IBS in 80 separate study populations containing 260,960 subjects. Pooled prevalence in all studies was 11.2% (95% CI, 9.8%-12.8%). The prevalence varied according to country (from 1.1% to 45.0%) and criteria used to define IBS. The greatest prevalence values were calculated when ≥3 Manning criteria were used (14%; 95% CI, 10.0%-17.0%); by using the Rome I and Rome II criteria, prevalence values were 8.8% (95% CI, 6.8%-11.2%) and 9.4% (95% CI, 7.8%-11.1%), respectively. The prevalence was higher for women than men (OR, 1.67; 95% CI, 1.53-1.82) and lower for individuals older than 50 years, compared with those younger than 50 (OR, 0.75; 95% CI, 0.62-0.92). There was no effect of socioeconomic status, but only 4 studies reported these data.

CONCLUSIONS

The prevalence of IBS varies among countries, as well as criteria used to define its presence. Women are at slightly higher risk for IBS than men. The effects of socioeconomic status have not been well described.

Effect of gender on prevalence of irritable bowel syndrome in the community: systematic review and meta-analysis

OBJECTIVES

Irritable bowel syndrome (IBS) is thought to be commoner in women. However, no systematic review has confirmed whether this is the case, or assessed whether any proposed female preponderance remains stable according to geography and criteria used to define IBS. Nor has effect of gender on subtype of IBS been examined systematically.

METHODS

MEDLINE, EMBASE, and EMBASE Classic were searched (up to October 2011) to identify population-based studies reporting prevalence of IBS in adults (≥15 years) according to gender, and defined using symptom-based criteria, or questionnaire. The prevalence of IBS in women and men was extracted for all studies, and according to study location and diagnostic criteria used, and compared using odds ratios (ORs) with 95% confidence intervals (CIs). Prevalence of each subtype of IBS, according to predominant stool pattern, was compared in women and men with IBS.

RESULTS

Of the 390 papers evaluated, 56 studies containing 188,229 subjects were eligible. The OR for IBS in women, compared with men, in all studies was 1.67 (95% CI: 1.53-1.82). Prevalence of IBS was not significantly higher in women, compared with men, in South Asian, South American, or African studies. The OR was highest with the Rome I criteria (1.99; 95% CI: 1.76-2.25), and lowest with the Rome II criteria (1.40; 95% CI: 1.24-1.59). Women with IBS were more likely to exhibit the constipation-predominant subtype (OR: 2.38; 95% CI: 1.45-3.92), and less likely to meet criteria for the diarrhea-predominant subtype (OR: 0.45; 95% CI: 0.32-0.65) than men with IBS.

CONCLUSIONS

Prevalence of IBS appeared modestly higher in women, and this remained relatively stable according to geography and criteria used to define its presence. However, among individuals with IBS, subtypes varied according to gender.

Discrepancies between the responses to skin prick test to food and respiratory antigens in two subtypes of patients with irritable bowel syndrome

AIM

To compare the response to skin prick tests (SPTs) to food antigens (FAs) and inhalant allergens (IAs) in patients with two subtypes of irritable bowel syndrome (IBS) and healthy controls.

METHODS

We compared the results of SPTs for IAs and FAs in 87 volunteers divided into three groups: diarrhea predominant IBS (D-IBS) Group I (n = 19), constipation predominant IBS (C-IBS) Group II (n = 17), and normal controls Group III (n = 51).

RESULTS

Of the 285 tests (171 for FAs and 114 for IAs) performed in Group I we obtained 45 (26.3%) positive responses for FA and 23 (20.1%) for IA. Of the 153 tests for FA in Group II, we obtained 66 (20.1%) positive responses, and of the 102 tests for IA, we obtained 20 (19.6%) positive responses. Of the 459 tests for FA performed in Group III, we obtained 39 (84%) positive responses, and of the 306 for IA, we obtained 52 (16.9%) positive responses. The numbers of positive responses were not significantly different between the three groups, but in the D-IBS group, the number of SPT FA responses differed significantly from those for the other two groups (P > 0.01).

CONCLUSION

Despite the small number of cases studied, the higher reactivity to FAs in Group I compared to Groups II and III adds new information, and suggests the presence of a possible alteration in intestinal epithelial function.

Alterations of food antigen-specific serum immunoglobulins G and E antibodies in patients with irritable bowel syndrome and functional dyspepsia

BACKGROUND

Post-prandial worsening of symptoms as well as adverse reactions to one or more foods are common in the patients with functional gastrointestinal diseases, such as irritable bowel syndrome (IBS) and functional dyspepsia (FD). However, the role played by true food allergy in the pathogenesis of these diseases is still controversial and there are no well-established tests to identify food allergy in this condition.

OBJECTIVE

To investigate serum food antigen-specific IgG, IgE antibody and total IgE antibody titres in controls and patients with IBS and FD, and to correlate symptoms with the food antigen-specific IgG titres in IBS and FD patients.

METHODS

Thirty-seven IBS patients, 28 FD patients and 20 healthy controls participated in this study. Serum IgG and IgE antibody titres to 14 common foods including beef, chicken, codfish, corn, crab, eggs, mushroom, milk, pork, rice, shrimp, soybean, tomatoes and wheat were analysed by ELISA. Serum total IgE titres were also measured. Last, symptomatology was assessed in the study. Results IBS patients had significantly higher titres of IgG antibody to crab (P=0.000), egg (P=0.000), shrimp (P=0.000), soybean (P=0.017) and wheat (P=0.004) than controls. FD patients had significantly higher titres of IgG antibody to egg (P=0.000) and soybean (P=0.017) than controls. The percentage of individuals with detectable positive food antigen-specific IgE antibodies of the three groups did not show any significant differences (P=0.971). There were no significant differences between IBS patients, FD patients and controls in the serum total IgE antibody titres (P=0.978). Lastly, no significant correlation was seen between symptom severity and serum food antigen-specific IgG antibody titres both in IBS and FD patients.

CONCLUSION

Serum IgG antibody titres to some common foods increased in IBS and FD patients compared to controls. But there is no significant correlation between symptom severity and elevated serum food antigen-specific IgG antibodies in these patients.

Relationship between asthma and irritable bowel syndrome: role of food allergy

The increasing prevalence of both asthma and irritable bowel syndrome (IBS) are major health problems. One hundred twenty-five patients with asthma and 95 healthy subjects were included in this study. The rate of IBS was 29.6% and 12.7% (p < 0.005), and the incidence of food allergy was 7.2% and 2.1% (p > 0.05) respectively for asthma and control group. There was no significant association between asthma related parameters, IBS, and food allergy. There is not a single clear reason as to what causes IBS, so further studies are needed to clarify the potential pathogenic mechanisms underlying the association between IBS and asthma.

Food intolerance and skin prick test in treated and untreated irritable bowel syndrome

AIM: To correlate the clinical features of treated and untreated patients with irritable bowel syndrome (IBS) to the results of skin prick test (SPT) for food and inhalant allergens.

METHODS: We recruited 105 subjects to form three different target groups: treated group (n = 44) undergoing treatment for IBS, untreated group (n = 31) meeting the Rome II criteria without treatment for IBS, control group (n = 30) with no IBS symptoms.

RESULTS: SPT results were different among the three groups in which SPT was positive in 17 (38.6%) treated patients, in 5 (16.1%) untreated patients and in 1 (3.3%) control (P < 0.01). The number of positive SPTs was greater in the IBS group than in the control group (P < 0.001). The number of positive food SPTs was higher in the treated IBS group than in the untreated IBS group (P = 0.03).

CONCLUSION: Positive food SPT is higher in IBS patients than in controls.

Irritable bowel syndrome in young and elderly patients with stable asthma

BACKGROUND

It has been speculated that asthma and irritable bowel syndrome may share common pathophysiological processes.

AIM

To estimate the prevalence of irritable bowel syndrome in young and elderly patients with stable asthma.

PATIENTS AND METHODS

Sixty-five young (age < 60 years) and 66 elderly (age > or = 60 years) stable asthmatics, and 119 age-matched healthy volunteers were enrolled. In all participants, presence of irritable bowel syndrome, quality of life and psychological status were evaluated.

RESULTS

The prevalence of irritable bowel syndrome in asthmatic group was higher than that in the control group (27.5% versus 16.8%; odds ratio, 1.8 [1.0-3.4]; p=0.04). The prevalence of irritable bowel syndrome was significantly higher in young asthmatics than in age-matched healthy controls (36.9% versus 20.3%; odds ratio, 2.2 [1.0-5.1]; p=0.04) and than in elderly asthmatics (36.9% versus 18.2%; odds ratio, 0.3 [0.1-0.8]; p=0.01). Logistic regression analysis identified the younger age (odds ratio, 2.1 [1.1-3.8]; p=0.01), and the presence of asthma (odds ratio, 1.9 [1.0-3.5]; p=0.03) as independent risk factors for irritable bowel syndrome in all participants after adjusting for gender. We also found impaired quality of life to be associated with the presence of irritable bowel syndrome and asthma in all participants after adjusting for age and gender.

CONCLUSION

The prevalence of irritable bowel syndrome appears to be significantly higher in young asthmatics, but not in elderly asthmatics, compared to age-matched healthy counterparts. Potential pathogenic mechanisms of higher irritable bowel syndrome prevalence in young asthmatics need to be explained by further studies.